132
COMPARISON OF ARTHROPOD ABUNDANCE AND DlVERSlTY IN INTERCROPPING AGROFORESTRY AND CORN MONOCULTURE SYSTEMS IN SOUTHERN ONTARIO Heather Dawn Howell A thesis submitted in confomity with the requirements for the degree of Master of Science in Forestry Graduate Faculty of Forestry University of Toronto @Copyright by Heather Dawn Howell, 2001

efek tumpangsari thdp keragaman arthropod

Embed Size (px)

Citation preview

Page 1: efek tumpangsari thdp keragaman arthropod

COMPARISON OF ARTHROPOD ABUNDANCE AND DlVERSlTY IN INTERCROPPING AGROFORESTRY AND CORN

MONOCULTURE SYSTEMS IN SOUTHERN ONTARIO

Heather Dawn Howell

A thesis submitted in confomity with the requirements for the degree of Master of Science in Forestry

Graduate Faculty of Forestry University of Toronto

@Copyright by Heather Dawn Howell, 2001

Page 2: efek tumpangsari thdp keragaman arthropod

National Library 1*1 ofCanada Bibliothèque nationale du Canada

Acquisitions and Acquisitions et Bibliographie Services services bibliographiques

The author has granted a non- exclusive licence aüowing the National Libmy of Canada to reproduce, loan, distribute or seil copies of this thesis in microform, paper or electronic formats.

The author retains ownership of the copyright in this thesis. Neither the tbesis nor substantial extracts fiom it may be printed or otherwise reproduced without the author' s permission.

L'auteur a accordé une licence non exclusive permettant à la Bibliothèque nationale du Canada de reproduire, prêter, distribuer ou vendre des copies de cette thèse sous la forme de microfiche/fih, de reproduction sur papier ou sur format électronique.

L'auteur conserve la propriété du droit d'auteur qui protège cette thèse. Ni la thèse ni des extraits substantiels de celle-ci ne doivent être imprimes ou autrement reproduits saas son autorisation.

Page 3: efek tumpangsari thdp keragaman arthropod

FACULTY OF FORESTRY University of Toronto

DEPARTMENTAL ORAL EXAMINATION FOR THE DEGREE OF MASTER OF SCIENCE IN FORESTRY

Examination of Ms. Heather HOWELL

Examination Chair's Signature: &&J%/

We approve this thesis and affim that it meets the departmental oral examination requirements set dom for the degree of Master of Science in Foresby.

Examination Cornmittee:

Page 4: efek tumpangsari thdp keragaman arthropod

Abstract

Cornparison of arthropod abundance and diversity in intercropping agroforestry and corn monoculture systems in southem Ontario.

Master of Science in Forestry. 2001. Heather Dawn Howell. Faculty of Forestry, University of Toronto

Arthropod communities were compared between a corn (Zea mays L.)

monoculture and a corn intercropped agroforestry system in southern Ontario during

1998 and 1999. Pan trap data were used in June 1998 while malaise trap data were

examined between June-September 1999. Arthropod abundanœ, representation by

functional group, and hymenopteran family richness and diversity were al1 compared

between the intercropped and the monoculture sites. Differenœs in arthropod

abundance within the intercropped system were also cornPa& between: 1) tree rows

with Norway spruce (Picea abies (L.) Karst.) or btack walnut (Juglans nigra L.); and 2)

tree rows and crop alleys. Taxa such as Opiliones. Dennaptera and Carabidae, which

are associated with organic litter areas that provide shelter during the day, were

significantly higher in the agroforestry system than in the monocuiture system. The

abundance of Hymenoptera, and several of its families, was also significantly higher in

the agroforestry site than in the monoculture site, atthough no differences were

observed in temis of overall family richness and diversity. There were significantly

higher numbers of parasitoids and detritivores in the intercropped agroforestry system

than in the monoculture system, and the intercropped treatment also supported a

significantly higher ratio of parasitoids to herbivores. My results suggest that

intercropping trees with crops such as corn monoculture can improve pest management

by providing habitat to augment natural enemies populations.

Page 5: efek tumpangsari thdp keragaman arthropod

Dedication

During the time when I was struggling through this thesis. my little sister

Catherine Middleton and my father-in-law Glen Howell undement their own momentous

challenges after being diagnosed with cancer. I would like to dedicate my thesis to both

of them for having the strength and the courage to overcome their difficult batUe and to

thank them for the love and encouragement that they gave me during the course of this

work.

iii

Page 6: efek tumpangsari thdp keragaman arthropod

Acknowledgement I wish to thank the many people who have helped me through this adventure.

f irst and foremost, I would like to extend my sincere thanks and appreciation to rny

supervisor, Dr. Sandy Smith (University of Toronto, Forestry) for providing me with the

opportunity to do this study, in addition to her assistance and understanding throughout

the development of this thesis. I would also like to extend my gratitude to my cornmittee

members for their insightFul guidance and advice: Dr. Andy Kenney (University of

Toronto, Forestry) for expanding my knowledge of agroforestry systems and for his

guidance in statistics; Dr. Chris Darling (Royal Ontario Museum, Toronto) for sharing his

knowledge and enthusiasm for the Hymenoptera; and Dr. Andy Gordon (University of

Guelph) for originally inspiring me to do this study many years ago during my

undergraduate days. Thanks also to Dr. Isabel Bellocq (University of Toronto, Forestry)

for participating in the defence phase and for providing helpful adviœ during the course

of the writing.

I would like to acknowledge the Faculty of Forestry for their financial support

through the Graduate Fellowship in Forestry award.

I am also greatly indebted to many people who have contributed a significant

amount of their time to help me in the field, the laboratory, with the statistical approach

and in other numerous ways. 1 would like to start by giving my deepest thanks to my

brother, Doug Middleton, who volunteered a large number of hours helping me out in

the field and in the laboratory. Large appreciation also goes out to Ping Zhang, Chantal

Lalonde, Robin Thornton, Tanya Campolin and the Kentner family for helping me with

aspects of field work. Special thanks to Naresh Thevathasan. Rick Gray (Agoroforestry

Research Group) and Peter Milton (University of Guelph Agricultural Research Stations)

Page 7: efek tumpangsari thdp keragaman arthropod

for their technical support with the research fields. Thank you to Alexi Baev for al1 of his

hard work in the laboratory with arthropod sorting and identification. I would also like to

give a note of appreciation to Deborah Yurman, Bill McMartin and Christine Vance who

gave me advice on my statistical analysis. My sincere gratitude goes to Dr. Fuhua Liu

(Faculty of Forestry), who spent many hours with me, analysing my data together while

patiently helping me to improve my knowledge of statistics. Thank you also to Robert

Moloney (Agriculture Co-op, Barrie), for his expert knowledge on aspects of agronomy. I

would also like to express my gratitude to Wendy Lake, Alison Howell, Rita Howell and

Glen Howell for their careful editing assistance.

Additionally, 1 would like to thank my friends and colleagues in my laboratory and

within the Faculty of Forestry for their warm friendship, advice and support over the

years I have been a student at the university. Most importantly I would like to thank my

family and friends, especially my mom and my grandfather, for their love and

encouragement throughout my thesis work.

1 have reserved my last note of heartfelt love and gratitude for my husband,

Morley Howell, who has given me the tremendous technical, financial and ernotional

support that made it possible to achieve my dream of completing a masters thesis.

Page 8: efek tumpangsari thdp keragaman arthropod

Table of Contents

.. Abstract ................................................................................................................................ II ... Dedication ......................................................................................................................... III

Acknowledgement .............................................................................................................. iv

.............................................................................................................. Table of Contents vi ... List of Tables ................................................................................................................... VIII

List of Figures ..................................................................................................................... x Introduction ......................................................................................................................... 1

RATIONALE .......................................................................................................................... 1

Literature Review .................................................................................................... ARTHROPODS IN AGROECOSYSTEMS ..........................................................................

Ecological Funetions of Arthropods in the Agroecosystem .................................. Importance of Hymenoptera in Agroecosystems .................................................

VEGETATIONAL DIVERSITY AND AGROECOSYSTEM STABILITY . Habitats with Adjacent Vegetation ................................. lntercropping Systems ..................................................

AGROFQRESTRY, ~NTERCROPP~NG AGROFORESTRY AND ART Agroforestry in North America ....................................

................

................ .................

'HROPODS . . .................

Intercropping Agroforestry in North America ........................................................... 7 8 Arthropods in Agroforestry Systems ........................................................................ 20

Materials and Methods ...................................................................................................... 27

SITE SELECTION FOR SAMPLING ......................................................................................... -28

DATA ANALY SIS .................................................................................................................. 34 Environmental Data ................................................................................................. 34 Arthropod Abundance ............................................................................................. 34 Arthropod Funetional Group Cornparison ( 1 999 Malaise Traps) ............................. 35 Hymenoptera Richness and Diversity (1 999 Malaise Traps) ................................... 36

Results ............................................................................................................................... 37

GENERAL ARTHROPOD ABUNDANCE .................................................................................... -41 1998 Pan Traps ....................................................................................................... 47 1999 Malaise Traps ................................................................................................. 47

Page 9: efek tumpangsari thdp keragaman arthropod

CONIPARISON OF NORWAY SPRUCE-INTERCROPPING AGROFORESTRY AND ............................................................................ CONVENTIONAL MONOCULTURE SYSTEMS 42

...................................................................................................... 1998 Pan Tmps 4 2 ................................................................................................. 1999 Malaise Traps 42

Functional Arthmpoâ Groups and Selected FamiliedOrders from 1999 Malaise ...................................................................................................................... Tmps 48

Hymenopteran Family Richness and Divetsity from 1999 Malaise Traps ............... 61

COMPARISON OF NORWAY SPRUCE AND BLACK WALNUT IN THE ~NTERCROPPING .................................................................................................. AGROFORESTRY SYSTEM -62

....................................................................................................... 1998 Par! Traps 62 ................................................................................................. 1999 Malaise Traps 62

COMPARISON OF TREE ROWS AND CROP ALLEYS IN THE ~NTERCROPPING ........................................................... AGROFORESTRY SYSTEM ..................................... ... -68

....................................................................................................... 1998 Pan Traps 68 ................................................................................................. 1999 Malaise Traps 68

COMPARISON OF ~NTERCROPPING AGROFORESTRY AND CONVENTIONAL MONOCULTURE SYSTEMS .................................................................................................... 77

COMPARISON OF NORWAY SPRUCE AND BLACK WALNUT TREE ROWS IN THE .......................................................................... 1 NTERCROPPING AGROFORESTRY SYSTEM -89

COMPARISON OF TREE ROM AND CROP ALLEYS IN THE INTERcROPPING ................................................................................................... AGROFORESTRY SY STEM -90

....................................................................................................................... Conclusions 93

Literature Sited ....................................................................................................... ...........97 Appendices ............................................................q....................O................................... 1 7

APPENDIX I . NUMBER OF ARTHROPODS IN EACH ORDER/CLASS USlNG PAN TRAPS DURING JUNE 1998 FROM NORWAY SPRUCE AND BLACK WALNUT SITES WiTHIN THE INTERCROPED AGROFORESTRY AND CORN MONOCULTURE SITES. AT THE GUELPH AGRICULTURAL RESEARCH STATION (~=60) ...................................................................... 1 7

APPENOIX 2 . NUMBER OF ARTHROPODS IN EACH ORDER USlNG MALAISE TRAPS DURING JUNE-SEPTEMBER 4999. FROM NORWAY SPRUCE AND BLACK WALNUT SITES WlTHlN THE INTERCROPPING AGROFORESTRY AND CORN MONOCULTURE

........................... STUDY SITES. AT THE GUELPH AGRICULTURAL RESEARCH STATION ( ~ 4 8 ) 118

APPENDIX 3 . NUMBER OF ARTHROPODS IN 61 SELECTED FAMILIES AND 2 SELECTED ORDERS THAT ARE REPRESENTING THE PARASITOID. PREDATOR. POCLINATOR. OETRITIVORE AND HERBlVORE FUNCTIONAL GUlLDSf CAUGHT IN JUNE-SEPTEMBER 1999 IN THE INTERCROPPING AGROFORESTRY NORWAY SPRUCE AND THE CORN MONOCULTURE STUDY SITE. AT THE GUELPH

.............................................. AGRICULTURAL RESEARCH STATION (~=32)

vii

Page 10: efek tumpangsari thdp keragaman arthropod

List of Tables Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6

Table 7

Table 8

Table 9

Summary of analysis methods and number of samples for each treatment cornparison and sampling season. ................................................ 31

Selected arthropod families and their associated functional groups' ............. 33

Environmental data collected from a weather station at the Guelph Agricultural Research Station during the summer of 1999. Data based on 3-day mean for each month in which malaise traps were placed in a given treatment. .......................................................................... 38

Mean abundance of arthropod orders collected in pan traps over a 3- day period from a corn intercropped agroforestry site and a monoculture site at the Guelph Agricultural Research Station. 5-8 June 1998 (N=40) .......................................................................................... 43

Mean abundance of arthropod orders collected in malaise traps over a 3-day period from a corn intercropped agroforestry site and a monoculture site at the Guelph Agricultural Research Station, June- September 1999 (N=32). ............................................................................... 44

Mean abundance of arthropod orders collected in malaise traps over a 3-day period from a corn intercropped agroforestry site or a monoculture site at the Guelph Agricultural Research Station, June-

............................................................................... September 1999 (N=32). 46

Arthropod abundance by functional groups from malaise traps operating for 3-day periods in a corn monoculture and an intercropped corn site at the Guelph Agriculture Research Station,

........................................................ Ontario, June-September 1999 (N=32). 49

Abundance of arthropods by functional groups from malaise traps placed three days each month in a corn intercropped agroforestry site and a corn monoculture site at the Guelph Agricultural Research

......................................................... Station. June-September 1999 (N=32). 50

Mean ratio between the number of predators or parasitoids and herbivores collected over three days using malaise traps in a corn monoculture site and a intercropped agroforestry site at the Guelph Agriculture Research Station, Ontario, June-September 1999

......................................................................................................... (N=32). -51

Table 10. Mean abundance of arthropod familiesforders in malaise traps over a 3-day period from a corn intercropped agroforestry site and a corn monoculture site at the Guelph Agricultural Research Station, June-

............................................................................... September 1999 (N=32). 53

Table II. Mean monthly abundance of selected arthropod familiesforders collected in malaise traps over a 3-day period frorn a corn intercropped agroforestry site and a corn monoculture site at the Guelph Agricultural Research Station. June-September 1999 (N=32). .......................................................................................................... 55

Page 11: efek tumpangsari thdp keragaman arthropod

Table 12. Mean number of hymenopteran famities in malaise traps from an intercropped agroforestry site and a corn monoculture site at the Guelph Agricultural Research Station. June-September 1999 - (N-32). ......................................................................................................... -61

Table 13. Mean abundance of arthropod orders collected for three days using pan traps in sites either intercropped with Noway spruce or black walnut at the Guelph Agriculture Research Station. 5-8 June 1998 (N=40). ......................................................................................................... - 63

Table 14. Mean abundance of arthropod orders collected for three days using pan traps in sites either intercropped with Nonivay spruce or black walnut at the Guelph Agriculture Research Station, June-September 1 999 (N=32). ................................................................................................ .64

Table 15. Mean monthly abundance of arthropod orders wllected for three days using pan traps in sites either intercropped with Norway spruce or black walnut at the Guelph Agriculture Research Station, June- September 1999 (N=32). .............................................................................. -66

Table 16. Mean abundance of arthropod orders collected in pan traps over a 3-day period in tree rows and crop alleys of sites in the intercropping agroforestry site at the Guelph Agricultural Research Station, 5-8 June 1998 (n=40). ......................................................................................... 70

Table 17. Mean abundance of arthropod orders collected in pan traps over a 3-day period in either the tree rows or crop alleys in the Norway spruce and black walnut treatments of lntercropping agroforestry site at the Guelph Agricultural Research Station. during 5-8 June 1998 (n=40). ................................................................................................. -71

Table 18. Mean abundance of arthropod orders collected in Malaise traps over a 3-day period in tree rows and crop alleys in the intercropping agroforestry site at the Guelph Agricultural Research Station, during

...................................................................... June-September 1999 (n=32).. 72

Table 19. Mean monthly abundance of arthropod orders collected in Malaise traps over a 3-day period the tree rows and crop alleys in the intercropping agroforestry site at the Guelph Agricultural Research Station, during June-September 1999 (n=32). .............................................. 73

Table 20. Mean abundance of arthropod orders collected in pan traps over a 3-day period in the tree rows or crop alleys of sites intercropped with either Norway spruce and black walnut in the lntercropping agroforestry field at the Guelph Agricultural Research Station, during

...................................................................... June-September 1999 (N=32). 75

Table 21. Eight parasitic hymenopteran families with their preferred hostsa, that were found to have significantly higher mean abundances in the intercropped agroforestry site at the Guelph Agricultural Research

..................................................................................... Station, during 1999. 83

Page 12: efek tumpangsari thdp keragaman arthropod

List of Figures Figure 1. Sampling design used in: a) the intercropping agroforestry sites with

pan traps during June 1998; b) the monoculture site with pan traps during June 1998; c) the intercropping agroforestry sites with malaise traps during June-September 1999; and d) the monoculture site with malaise traps during June-September 1999. ................................... 29

Figure 2. Relationship between arthropod abundance in malaise traps over a 3-day monthly mean temperature at the Guelph Agricultural Research station during 1999. (n=l 1 )(--regression 95%

.................................................................................................... confidence) 39

Figure 3. Relationship between arthropod abundance in malaise traps mer a 3-day monthly mean percent relative humidity at the Guelph Agricultural Research station during 1999. (n=l 1 ) (---regression

............................................................................................ 95% confidence) 40

Page 13: efek tumpangsari thdp keragaman arthropod

Introduction

Rationale

Agroecosystems fonn the dominant ecosystern in southem Ontario, covering

5,201.981 ha or 45% of the land base in the region (Statistics Canada, 1999). The

structure and functioning of the agroecosystem, like al1 natural ecosystems. is

dependent on interactions between soil, water, solar radiation and biological organisms.

Agroecosystems are different from natural ecosystems because they require human

manipulation to keep them functioning artficially in order to meet our needs for food,

fibre and other products (Agriculture and Agri-Food Canada, 1 997a; Altieri, 1 994). Over

the past several decades, growing demand for agricultural products has led to a rise in

high-yield intensive agricultural production throughout the region. This growing

industrialisation of agriculture has raised concems over environmental degradation and

the long-term sustainability of agricultural production in southem Ontario (Xu and Mage,

2001 ; Murray, 1997).

In response to the detrimental environmental effects of agriculture practices,

Agriculture and Agri-Food Canada (AAFC) has set out to find ways to address

environmental sustainability in Canadian agriculture. This directive recognises the

importance of agro-biodiversity. Diverse populations of organisms play an important role

in maintaining agricultural ecological systems (e.g. crop pollination or organic matter

decomposition), and the sustainability of Canadian agriculture and the agri-food sector

depends on conserving this natural biodiversity (AAFC, 2001). One of the many

commitrnents of AAFC is to use agraecosystem indicaton to measure changes in the

organisation and composition of biotic communities in relation to agricultural land

practices and cropping systems (AAFC. 1997b). It has also set out to increase

1

Page 14: efek tumpangsari thdp keragaman arthropod

knowledge and understanding of biodiversity in agriculture, to find ways to minimize

adverse impacts of agricuftural practices on biodiversity, and to promote the

incorporation of biodivenity considerations into the fan-level decision making process

(AAFC 2001 ; AAFC, 1997 a).

lntercropping agroforestry is a system that may alleviate agricultural

environmental problems and help increase biological diversity in the agroecosystem.

This system (also known as alley cropping) involves the cutivation of annual or

perennial crops between ro is of trees or shwbs. An annual i n m e is derived from the

agricuttural crop. while a longer-terni income can be gained from the tredshrub

products (USDA, 2000; Hodge et al., 1999; Nair, 1990). The environmental benefits that

have been attribut4 to this systern include: reduction of wind and water erosion, a

modfied microclimate for improveâ crop production, improved utilization of nutrients,

and amelioration of biodiversity (Williams et al., 1 997; USDA, 1 997).

lntercropping has historically been practised in many temperate regions of the

world (Byington, 1990). For example, during the establishment of fruit orchards in

southern Ontario, it is wmmon to cultivate crops such as strawberries (Fragana x

annassa Duch. ) between the rows of the young trees (Leuty, 1999: Gordon and

Williams, 1991). Yet the majority of the scientific research on intercropping agroforestry

has been perforrned in the tropics, creating scientific knowledge that is mainly based on

the conditions of this region (Stamps and Linit, 1999a). Fortunately there has been a

growing interest in temperate intercropping agroforestry over the last 20 yean, and

scientific research examining this systern has increased dramatically (Gordon et al.,

1 997). One important aspect of temperate intercropping agroforestry is its role in the

conservation of biodiverstty within the agroecosystem (Newman and Gordon. 1997).

Page 15: efek tumpangsari thdp keragaman arthropod

3

Previous studies have examined the effects of intercropping agroforestry on birds and

earthworms (Price, 1 999; Wlliams et al., 1 996).

Arthropods account for the largest percentage of animal biomass and biodiversity

in the agroecosystem (Paoletti et al., 1992; Pimentel et al., 1992). and they perfotm

many essential roles in most agro-ecological processes (Lasalle. 1999; Swift et al..

1996; Bond, 1993). Their involvement in these processes makes them useful bio-

indicators for assessing agroecosystem sustainsbility (Paoletti, 1 999; van Straalen,

1 997; Holloway and Stork, 1 991).

Unfortunately. very little research has been conducted on arthropods and

intercropping agroforestry systems in the temperate region (Stamps and Linl, 1998).

With only a very few exceptions, the majority of arthropodfintercropping agroforestty

research has taken place in the tropics (Rao et al., 2000; Stamps and Linit, 1998).

Further research is needed if intercropping agroforestry is to be promoted in temperate

agroecosystems. This is especially true because many growers need reassurance that

intercropping agroforestry will not increase p s t problems before they decide to

implement this system (Stamps and Linit, 1998). In addition, research clearly needs to

be conduded in several agro-ecological zones throughout the temperate region. using

different intercropping agroforestry designs. Such research would contribute to our

understanding of how various spatial arrangements and biological/micro-climate

aspects affect the distribution of arthropods.

Research Goal

The primary objective of my study was to examine and compare the arthropod

communities in an intercropping agroforestry system and a conventional monoculhire

corn (Zea mays L.) system in southern Ontario. Several aspects of the arthropod

community were compared: 1) the abundance of arthropods acwrding to their

Page 16: efek tumpangsari thdp keragaman arthropod

4

taxonomie order. 2) the abundance of arthropods acmrding to their fundional group. 3)

the ratio between herbivore and natural enemy populations. and 4) famiiy richness and

divenity in the hymenopteran order.

The secondary objective was to examine how physical aspects of the

intercropping agroforestry field affect the abundance of arthropods within this system.

Arthropod populations were compared between two sites planted with different tree

species. Noiway spruce (Picea abies (1.) Karst) and black walnut (Juglans nigm L.).

Comparisons were also made between the tree rows and crop alieys in the agroforestry

system.

Thesis Structure

This thesis proceeds through five main sections. First. a comprehensive literature

review is provided. outlining some of the broader issues related to arthropods in the

agroecosystem, vegetational diversity, and agroforestry. A description of the materials

and methods forms the second section. This is followed by a resuits section. which

presents findings for each of the three study comparisons. A general discussion of the

effects observed in each of the results sections constitutes the fourth component of the

thesis. The last section concludes the thesis and includes a discussion of future

recommendations.

Page 17: efek tumpangsari thdp keragaman arthropod

Literature Review

Arthropods in Agroecosystems

Arthropods play important roles in agroecosystems as dominant pollinators of

crops, natural control agents of many agricuitural pests, and other ôeneficial activities

such as building and renewal of agricuitural soils (Lasalle, 1999; Hill, 1997). lt has been

esthated that arthropod pests destroy 13% of the crops grown world-wide (Pimentel,

1 995). The value of this loss in the United States alone was assessed in 1990 to be

$6.6 billion (Metcalf, 1999). However, the estimated economic value of the services

provided by the beneficial insect groups is much greater. For instance, the value of the

pollination service provided by honey bees in the United States. is estimated b be

between $1.6 and $5.7 billion annually (Southwick and Southwick, 1992).

Arthropods are the dominant phylum in the animal kingdom in ternis of divenity

of species and shear abundance (Price, 1997; Mitchell et al., 1988). In addition,

arthropods are also the dominant fauna within the agroecosystem, with the largest

biomass and diversity (Paoletti et al.. 1992). Surveys in temperate and tropical

agroecosystems have found from 262-1000 species of arthropods per hectare, making

up an estimated 1000 kg of fresh weight biomass per hectare (Pimentel et al., 1992).

Many factors influence arthropod population dynamics within agroecosystems.

including conventional agricultural practices (e-g. annual cropping systems), which often

lead to frequent intense disturbanœ. These disturbanœs hinder the survival of various

arthropods, including many beneficial organisms. They also allow more adaptable

arthropod species to thrive. such as many agricuttural pests (Letoumeau, 1998).

Practices such as soi1 tillage. the use of fertilisers, soi1 fumigation, and the use of

pesticides, have al1 been found to affect the abundance and diversity of arthropods in

5

Page 18: efek tumpangsari thdp keragaman arthropod

6 the agroecosystem (Noms and Kogan, 2000; Kromp, 1999; Kross and Schaefer, 1998;

Bwij and Noorlander, 1 992; Paoletti et al., 1992; Wnter et a/. , 1 990; Stinner et al.,

1990, 1986). Arthropod populations can also be affected by the structure of the

agricultural landscape. These factors include sire and shape of agricultural fields as

well as the composition and the architecture of the vegetation and its surrounding

habitats (Gurr et al.. 1998; Fry, 1995; Hoit et al., 1995; Landis, 1994).

Arthropod populations are very useful biological indicators to measure the effeds

of d ifferent ag ricultural pradices and landscapes because they are affected by changes

within the agricukural environment. Arthropods are diverse, abundant, ecologicaliy

important, plus easy to collect at low cost (Finnamore, 1996). The combination of these

factors means that they are commonly used in ealogical and agricultural research

studies (Paoletti et al., 1992) and can be used to compare intercropping agroforestry

with conventional monoculture cropping in ternis of sustainability and biological

diversity.

Ecological Functions of Arairopods in the Agroecosystem

Arthropods can be classified into different functional groups according to their

feeding behaviours or by their interactions with other organisms or elements within the

ecosystem. They are arranged into trophic groups or trophic levels according to their

feeding relationships in the ecological community. with plants at the first level,

herbivores at the second level, and carnivores and parasitoids at the third level (Price,

1997). In addition, arthropods can be categorised into guilds depending on the feeding

method they use in exploiting a common resource (Root, 1973). For instance,

herbivores can be divided into subgroups such as sap-feeding and strip-feeding (Krebs,

1994). LaSalle (1 999) groups arthropods living in agroecosystems into five functional

Page 19: efek tumpangsari thdp keragaman arthropod

7 groups: pollinators. predaton, parasitoids. herbivores and detritiiores. For the purpose

of my research here, arthropods have been classified into similar groups as those

proposed by Lasalle (1 999).

Pollinators

Man y hig her-level plants (ang iosperms) within the agroewsystem are dependent

on arthropod pollinators for fertilisation because they transport pollen from the stamen

of one flower to the stigma of another fiower (Neff and Simpson. 1993). The production

of rnany economically important food, fibre, and forage crops rely on pollination by

arthropods, with the exception of cereal crops, which are all wind-pollinated (Borror et

al., 1989). Arthropods that are involved in pollination include Diptera (flies), Coleoptera

(beetles), Lepidoptera (moths and buttemies) (Wallace et al., 1991 ). and most

importantly, members of the Apoidae superfamily (bees) of the Hymenoptera (Neff and

Simpson, 1993; O'Toole, 1993).

Hen5ivores

Herbivores play a central role in agroecosystems as consumers of plants and as

food for predaton. Approximately one quarter of al1 insect species are phytophagous

(Strong et a/., 1984) and can constitute between 45.80% of individual arthropods found

in some agroecosystems (Nentwig, 1998). Herbivores are found in many orders

including : the Acarnia (mite), Diptera, Hymenoptera, Thysanoptera, Phasmida,

Lepidoptera, Orthoptera, Demaptera, Hemiptera, Coleoptera, Lepidoptera and

Hornoptera (Letourneau, 1997), with the last three k i n g the most notable (Barbosa.

1998). Although they are generally considered pests within the wntext of agricultural

production, some herbivores can also be viewed as biological control agents of weeds

(Lasalle. 1999). Unfortunately, not al1 weed-consuming arthropods are beneficial

Page 20: efek tumpangsari thdp keragaman arthropod

8 because many feed on weeds for one part of the season and later move on to consume

cuitîvated crops (Norris and Kogan. 2000).

The most notable arthropd herbivores in the com~ropping systems of southem

Ontario are: the European corn borer (Pyralidae: Ostrinia nubilalis (Hubner)); corn

rootwoms (Ch rysomelidae: Diabmtica spp. ); the corn leaf ap hid (Aphidae:

Rhopalosiphurn maidis (Fitch)); and the a rmyworm (Noctuidae: Pseudaletia unipuncta

(Haworth)) (OMAFRA, 1999; Rice, 1996).

Detritivoms

Many arthropods within the agroecosystem are important wmponents in soil,

plant and animal decomposition. These detntivores help to increase the rate of litter

breakdown by shredding and masticating plant tissues, thereby increasing the litter

surface area available for fungi and bacteria (van Straalen. 1997). Such arthropods also

help ameliorate soi1 aeration and soi1 moisture by tunnelhg within the humus layers and

decaying roots (Marshall et al., 1 982). Collembola (springtails) and Acamia (mites) are

the principal detritivores within agroecosystems (Wardle et a/. . 1 999). althoug h other

arthropods such as lsopoda (woodlice) (Paoletti and Hassall, 1999) and Dipoloda

(rnillipedes) (Cloudsley-Thompson, 1958) are also involved in the decomposition

process.

Predators

Predators arthropods are exceedingly beneficial in agroecosystems because

they help to naturally regulate populations of herbivores (Booij and Noorlander. 1992;

Luff, 1983). Many predatory species are renowned for their ability to suppress

phytophagous pest populations in agroecosystems. For example, ladybird beetles

(Coccinellidae) have been used in several biolog ical control programs (1 perti. i 999).

Page 21: efek tumpangsari thdp keragaman arthropod

9 Even though some predators may have only minor impact on an individual basis. their

overall population can contnbute greatly to pest mortality (Barbosa and Wratten, 1998).

In general, predators tend to be more polyphagous than parasitoids and will feed on

many different kinds of arthropod prey, including beneficial species. The ability to eat

many diff'erent kinds of prey allows some predators to survive through limited prey

conditions (Lasalle, 1999). Orders and families of some important predatory groups

within agroecosystems include: Diptera (Ernpididae, Syrphidae, Dolichopodidae,

Asilidae); Arachnida; Hymenoptera (Formicidae. Pornpilidae, Vespidae); Coleoptera

(Coccinellidae, Carabidae, Staphylinidae. Cantharidae); Hemiptera (Anthocoridae.

Nabidae. Reduviidae); and Neuroptera (Chrysopoidae, Hemerobiidae) (Lasalle, 1999;

Stelzl and Devatak. 1 999; Helenius, 1998; Nentwig, 1998; Brothers and Finnamore,

1 993; LaSal te and Gauld, 1 993; Borror et al.. 1 992).

Parasitoids

Like predators, parasitoids play a major role in maintaining the ecological

balance in arthropod populations, and often regulate the number and density of

herbivorous pests (Landis and Menalled, 1 998; Lasalle and Gauld, 1993). Parasitoids

affect their target host by living in or on the body of a single organism during their larval

stage. eventually killing it or suppressing its growth (Price, 1997). In most cases,

herbivorous arthropods are attacked by more than one parasitoid species, while many

parasitoid species attack more than one host (Altieri et al.. 1993). The members of the

order Hymenoptera make up the largest proportion of the parasitoid group, although

other important parasitoid species can be found in the order Diptera (Lasalle. 1999). for

example the family Tachinidae (McAlpine. 1981).

Page 22: efek tumpangsari thdp keragaman arthropod

Importance of Hymenoptera in Agroecosystems

The order Hymenoptera is one of the rnost diverse and abundant orders within

the class Insecta. With well over 115, 000 described species in 80 different families

(Lasalle and Gauld, 1903). this order represents approximately 14% of al1 the narned

insect species in the world (Danks, 1988). Within temperate regions, the Hymenoptera

is the richest in ternis of species (Lasalle and Gauld, 1993). In fact, there are

approximately 7, 000 species of Hymenoptera in Canada. representing one quarter of

the country's total number of scientifically named insects (Mason and Huber, 1993).

In addlion to their divenw, the Hymenoptera are also recognised for their

different functional roles within ecosystems. The majority of families are

entomophagous (feeding on inseds) either as parasitoids or predators (Masner et al.,

1 979). while others are phytophagous (plant feeders) or xylophagous (wood eating)

(Lasalle and Gauld, 1993). Some families include a wide range of feeding habits, such

as the family Formicidae (ants), whose members feed on other insects, fungi, plants,

plant sap. nectar, honey dew, flesh of dead animals, etc. (Holldobler and Wilson,l990).

The importance of the Hymenoptera in agroecosystems is highlighted by the

variety of crucial roles its members play. For example, the principal pollinators of

fiowering plants are bees, including honeybees. bumblebees and solitary bees

(O'Toole. 1993), while the dominant parasitoids are also hymenopterans (Lasalle, 1999;

Altieri et al., 1993). In addition, many species are important predaton, keeping

arthropod populations balanced within agroecosystems. In fact, the predators and

parasitoids from this order have k e n found to interact with more arthropod prey

species than any other terrestrial arthropod order (Lasalle and Gauld, 1993).

Because of their importance in the fundioning of agroecosystems, the order

Hymenoptera can be considered important indicators of ecosystem health and stability.

Page 23: efek tumpangsari thdp keragaman arthropod

As such. they are often used to examine the effects of agricuitural practices, such as

soi1 tillage (Lobry de Bniyn. 1999) and pesticide and fertiliser usage (Paoletti. 1999;

Jensen. 1997; Bohac and Fuchs, 1991) on agricultural sustainability. In addition, they

can provide information on changes in structural components such as the quantity and

influence of natural habitats in agroecosysterns (Svensson et al.. 2000; Unruh and

Messing, 1999; Bruck and Lewis. 1998; Lagerlof et al.. 1992).

My study focuses on the order Hymenoptera because of their significant and

broad-ranging functions. Specifically, my thesis examines differences in the abundance.

richness and diversity of hymenopteran families between a monoculture field and one

intercropped wit h trees (agroforestry).

Vegetational Diversity and Agroecosystem Stability

The theory that increases in vegetational diversity will lead to ecosystem stability

through a reduction in pest outbreaks has been widely debated (Risch et al.. 1983). It

has frequently k e n offered as an explanation for the apparent high levels of herbivore

damage in monocuitures and less severe or infrequent injuries in natural polycutture

systems (Letoumeau, 1997; van Emden and Williams, 1974).

There are three main ecological hypotheses that expfain why pest populations

might be lower in multi-species plant environments: 1) resource concentration; 2) plant

association resistance; and 3) the natural enemy hypothesis (Altieri, 1994). The

resource concentration hypothesis developed by Root (1 973) states that specialist

herbivores are more likely to detect and stay in habitats where their host plants are

concentrated and where their reproductive success is likely to be greatest. A reduction

in the density of the host plant resource, an alteration in the spatial arrangement of the

Page 24: efek tumpangsari thdp keragaman arthropod

12 host plant. or the interference of increased non-host plants abundance, are al1 thought

to inhibit herbivores from locating and exploiting their host plant resource.

Convenely, Tahvanainen and Root (1972) hypothesised that there exists a plant

association resistance to herbivore populations, possibly developed by means of the

complex vegetational structure, chernical environment and associated patterns of

microclimates in habitats where plant species are intemixed. Association resistanœ is

thought to be important to herbivores that are relatively small and dependent on

oifactory mechanisms to find their plant hosts. Non-host plant odoun may attract

herbivores and therefore act as decoys for the host plants (Pnce, 1997) or mask the

odours emitted from the host plant (Alieri, 1994).

Finally, the natural enemy hypothesis suggests that natural enemies will be

more abundant and diverse in vegetationally diverse environments than in monocultures

(Root, 1973). Vegetational diventty is thought to provide better environmental and

microclimatic conditions that help sustain or increase predator and parasitoid

populations. These conditions include greater availability of resources such as prey,

hosts, pollen and nectar, shelter, breeding and nesting sites, and improved microclimate

(Risch, 1981). Natural enemies are also thought to have access to a greater variety of

hosts or prey over a longer period of time in such habitats as wmpared to monocultures

(Andow and Risch, 1985).

The debate surrounding the validity of these three ewlogical hypotheses has

producad extensive literature review (Smith and McSorley. 2000; Tonhasca and Byme,

1994; Andow, 1991 ; Sheehan, 1 986; Kareiva, 1983; Risch et al., 1983). Andow (1 991 )

found that 53% of the studies he reviewed showed herbivores were less abundant (on a

population per plant basis) in polycultures than in monocultures. In 15-1 8% of the

cases, herbivores were more abundant, while 9% showed no difference and 20% had a

Page 25: efek tumpangsari thdp keragaman arthropod

13

varied response. In Russell's (1989) work, 50% of the studies found higher herbivore

mortality from predation and parasitism in vegetationally diverse systems than in

monocultures, however, he believed that most studies lacked adequate controls,

thereby preventing conclusive findings. On the other hand, Russell found that the

natural enemy hypothesis and the resource concentration hypothesis probably acted as

complernentary mechanisms in reducing the number of herbivores in the polycultures,

and that they should be dealt with simultaneously to achieve maximum herbivore

wntrol.

Habitats with Adjacent Vegetation

In traditional agricuttural fields where crops are grown annually, there are regular

and significant disturbances to arthropod communities through activities such as tilling,

planting, spraying, fertilising and harvesting (Aitieri, 1994). Some arthropods, such as

herbivorous pests, have adapted well to such disturbad habitats (Letoumeau, 1 997).

Other arthropod groups, such as the parasitoids, do not fare as well because they lack

adequate food and microhabitat resources (Landis and Menalled, 1998).

Wthin agricultural landscapes, arthropods appear to depend upon uncultivated.

vegetationally diverse habitats adjacent to agricultural fields. lnterest has been growing

in studying how these areas influence the density and distribution of arthropods within

agroecosystems (Burel and Baudry, 1995). A common view is that vegetationally

diverse habitats surrounding an agricultural field play an important rote in decreasing or

stabilising pest populations, while augmenting and conserving populations of beneficial

arthropods (Landis et al., 2000; Fry, 1995). These field margin environments are

considered beneficial habitats for many arthropods because they provide permanent.

undisturbed and sheltered sites for ovewintering, feeding and reproduction (Burel and

Page 26: efek tumpangsari thdp keragaman arthropod

14 Baudry, 1995). These margins are also thought to be important reservoirs for beneficial

insects to redonise agricultural fields (Dennis and Fry, 1992). Unfortunately, many

farmen view field edges as areas that harbour agricultural pests (Marshall and Smith,

1987; van Emden, 1981).

Many studies have examined the use of uncultivated field boundaries by various

arthropod communities, such as butterfiies (Dover et al.. 2000; Feber et al., 1996).

Woody borders (Holtand and Fahrig, 2000). weedy headlands. and grassy ditches

(Macleod, 1999; Thomas and Marshall, 1999; Varchola and Dunn, 1999; Hassall et al.,

1992; Kromp and Steinberger, 1992) are sorne of the habitats that have been studied to

detennine how agricultural landscape structures influence arthropod communities. Many

bordering areas supply critical arthropod habitat for food and shetter because they are

composed of a variety of plants that flower at different times over the year (Delaplane

and Mayer. 2000; O'Twle, 1993; Banaszak, 1992; Lagerlof et al., 1992). These areas

are ako vital for natural enemies because they provide alternative hosts or prey during

times of low pest host density, as well as pollen and nectar for adutts (Barbosa and

Wratten, 1998; Bugg and Pickett, 1998; Corbett, 1 998; Gurr et al., 1 998). Uncultivated

areas also provide stable, undisturbed refuges for predators and parasitoids to

oveminter, nest or rest (Landis et al., 2000; Beane and Bugg, 1998; Ferro and McNeil,

1998).

lntercropping Systems

While a traditional agricultural landscape provides a small degree of undisturbed.

vegetationally diverse habitat in adjacent areas, additional habitats can be created

directly in the agricuttural field. lntercropping is one way to accomplish this. Examples of

this technique include: allowing long grassy ridges to bisect fields (Netwig et al.,

Page 27: efek tumpangsari thdp keragaman arthropod

15 1998;Thomas et al.. 1992), harvesting two different annual crops at separate times. and

undersowing different crop species (Helenius, 1998; Coll, 998).

Research on hedgerows has shown that some natural enemies do not venture

far into adjaœnt agricuitural fields. but instead stay close to the woody edges of the

rows (Lewis, 1969b). Further work on grassy within-field habitats has found that these

'islands' provide protected corridors for predatory arthropods, which allows for rapid

colonisation into adjaœnt agricuttural fields (Lys and Nentwig. 1994, 1992). These

grassy stnps do not appear to increase populations of pest species. and populations of

some species actually decline due to the improved balance of herbivores and natural

enemies (Nentwig et al., 1 998).

lntercropping agroforestry is another method that may produce simibr effects on

arthropod communities as the grassy field stnps. Rows of woody plants placed across

an agricuitural field can create beneficial within-field habitat for arthropod communities,

and improve vegetational diversity. When compared to other intercropping techniques.

this design provides better habitat for an assortment of arthropod communities. both in

time and space (Stamps and Linit, 1998). Woody plants are superior to smaller plants

because they provide a larger habitat space with greater architectural wmplexity, and

thereby have a greater effect on the microclimate of the surrounding areas (Lewis,

1969a). Woody plants also provide a more stable environment for arthropods over an

extended period of time because they tend to live longer than other herbaceous plants

(Stamps and Linit, 1998).

In addition to enduring and expanded habitat space, many woody species are

alternative food sources for arthropod communiües (Crane, 1985; Howes. 1979).

Flowering vegetation in the understory of tree rows provides additional nectar and

pollen sources as well as large amounts of plant biomass for herbivorous arthropods.

Page 28: efek tumpangsari thdp keragaman arthropod

16

This in tum becomes habitat for alternative hosts of natural enemies, allowing them to

survive when prey populations are low in adjacent agricultural M d s (Murphy et al.,

1 998).

The in-field habitat provided by woody plants used in intercropping agroforestry

systems has the potential to produœ desirable e M s on arthropod communities.

Therefore, one of the main goals of my research will be to determine l tree rows provide

a beneficial habitat for arthropods by comparing the arthropod populations and pest to

natural enemy ratios between an intercropped agroforestry system and a monoculture

system .

Agroforestry, lntercropping Agroforestry and Arthropods

The practice of integrating trees within agricultural systems. known as

agroforestry. has k e n used around the world for hundreds of yean. It was not until the

late 1970's that interest in the application of agroforestry and scientific research on

agroforestry systems began to fiourish (Nair, 1996). Many practitioners promote

agroforestry as an economic and environmental alternative to conventional agriculture

systems. At the same time. they acknowledge that little is known about how these

systems function. This shortcoming must be addressed in order to promote agroforestry

in agriculture.

One example of this is the need for a better understanding of the biological,

physical and chemical interactions that occur in agroforestry systems (Gordon et al.,

1 997), especially in terms of application and adoptability for specific agricultural

production systems (Raintree, 1990). The advantages and disadvantages of

agroforestry must also be compared to other land-use systems. pnmarily monoculture

Page 29: efek tumpangsari thdp keragaman arthropod

systems that currently dominate agriculture and forestry (MacDicken and Vergara,

Agroforestry in North America

Agroforestry is a marriage between the practices of agriculture and forestry. It

has k e n defined as: ". . . a land use that involves deliberate retention, introduction, or

mixture of trees or other woody perennials in croplanimal production fields to benefit

from the resultant ecological and economic interactions." (MacDicken and Vergara,

1990). In NoNi America, there are several different types of agroforestry that fit this

definition. These c m be grouped into one of two categories: agrisilvicutture (crops and

trees, including s hm bs andlor vines) or silvopasture (pasture andlor animals and trees)

(Nair, 1990). The foms of agroforestry commonly practiced in Canada and the United

States include windbreak systems (woody plant barriers used to reduœ and redired

wind), silvopasture (trees grown in pasture with livestock). riparian forest buffers

(streamside forests made up of tree, shrub, and grass plantings), forest farming

(specialty crops grown or harvested from the forest), and intercropping (inter-planting

rows of trees with rows of crops in between) (Williams et al., 1997; Nair, 1996; Byington,

1 990).

Within North America, agroforestry systems are appealing to those looking for

alternative agrïcultural practices that provide improved environmental and economic

sustainability (Kurtz et al.. 1991 ). Some of the beneficial environmental characteristics

of agroforestry include increased wind and water erosion control, reduction of wind

speed, improved soi1 fertility though additional organic matter, microclimate regulation,

improved wildlife habitat, as well as filtering and biodegradation of excess nutrients and

pesticides (MacDicken and Vergara. 1990).

Page 30: efek tumpangsari thdp keragaman arthropod

18

Agroforestry systems are also viewed as an opportunistic approach to improving

farm profitability and economic stability (Nair, 1996). Econornic output potential per land

unit area is increased by the combination of product revenue from the trees plus the

crop andlor livestock (Williams and Gordon, 1992; Hoekstra, 1990). Production retums

from crops and livestock can also increase due to the environmental benefits provided

by trees. For instance, yields andlor the quality of valuable horticultural crops c m be

safeguarded by windbreaks, which shelter the crops from abrasion by windblown soi1

(Baldwin, 1988). Agroforestry also provides a way to integrate new products into the

f am enterprise, allowing for financial diversity from a range of different products. This in

tum creates an altemate source of income during financial down times for the main fam

product (USDA, 2000).

Several different tree species are comrnonly used within agroforestry systems in

North America. Black walnut (Juglans nigra L.) and pecan (Carya illinoensis (Wangenh. )

K. Koch) are commonly used in intercropping systems (Nair, 1996; Jackson, 1987) while

long leaf pine (Pinus palustris Miller) and loblolly pine (Pinus taeda L.) are used in

silvopasture systems in the United States (Williams et al.. 1 997). Green ash (Fraxinus

pensylvanica var. subintergenma (Va hl) Fem . ) , Siberian pea t ree (Caragana

aborescens Lamb.), Russian olive (Elaeagnus angustifolia L.), and various poplars

(Poplus spp.) are used in windbreaks and shelterbelts on the Great Plains (Byington,

1990). while Noiway spruce (Picea abies (L.) Karst.) and red pine (Pinus msinosa Al.)

are commonly found in windbreaks throughout Ontario (Williams et al., 1997).

lnbrcropping Agroforestry in North America

Next to windbreaks and silvopastural pradices, intercropping is increasingly

being adopted in North America as an effective agroforestry practice (Nair, 1996).

Page 31: efek tumpangsari thdp keragaman arthropod

19 Intercropping agroforestry (alley cropping) is the practice of growing two or more rows of

trees or shmbs, with the rows spaced apart to allow for cultivation of agronomic,

horticultural, or forage crops in the 'alleys' behnreen the rows of woody plants (USDA,

1997). This system has traditionally been used in North America during the

establishment of fruit or nut orchards, where famers grow horticultural crops between

rows of young trees (Nair, 1993). lntercropping agroforestry systems can also be

integrated with other land use pradices, such as Christmas tree production, or for

shifting agricultural land into recreational or urban devetopment (Hodge et al., 1999;

Rule et al., 1 993; W~lliarns and Gordon, 1 992).

Hardwood trees are the most common woody species utilized in intercropping

agroforestry systems in North America (USDA. 1997), with black walnut being the most

widely studied (Nair, 1993). Black walnut is a highly valueâ multipurpose tree that can

produœ timber, nutmeats and nutshells (Garrett et al., 1991). Veneerquality logs can

be marketed for several thousand dollars and nuts of high quality can be sold for $20

per 1 OOlb (US) (Byington, 1990). This tree species is also ideal for intercropping

agroforestry because it is one of the last to develop leaves in the spring, and the first to

defoliate in the fall, allowing for long perÏods of direct sunlight for the alley crops

(Williams et al., 1997). Black walnuts produce very little shade even when the canopy is

fully leafed out. allowing slightly less than 50% full sunlight (Moss, 1964). One drawback

in using this tree species is that it produces juglone, a plant growth inhibitor that may

impede specific broadleaf crops (Hodge et al.. 1999; Farrar, 1 995). although it is

compatible with grasses and other monocot crops (Williams et al.. 1997).

In a recent American survey (Nat. Associ. Res. Cons. Dev. Coun., 2000), 13% of

al1 respondents pradicing agroforestry used intercropping agroforestry techniques. The

main motivation behind increasing the use of intercropping agroforestry systems is

Page 32: efek tumpangsari thdp keragaman arthropod

20

usually financial, but other issues such as controlling erosion, improving wilâlife habitat

and irnproving water quality are also important A similar survey with agricuitural

landownen in southem Ontario found that most respondents 'knew very little' about

intercropping agroforestry (Matthews et al., 1993). suggesting that extension education

is needed to promote the benefits of agroforestry throughout the region.

Efforts to further Our understanding of agroforestry systems in Ontario have

originated from the University of Guelph. In 1989, the first North American Temperate

Agroforestry Conferenœ was held there as a forum for researchers, teachers,

extensionists. and praditioners to share up-todate information about temperate

agroforestry, including intercropping agroforestry (Williams, 1991). Several intercropping

agroforestry projects have k e n carried out within the province over the last two

decades, examining physical and chemical interactions within such systems, for

example: nutrients (Zhang , 1999; Thevathasan, 1998); microclimate (Simpson, 1 999,

Williams and Gordon, 1 995); biological interactions with weeds (Kotey. 1997);

earthworrns (Price, 1999); and birds (Williams et al., 1996).

In rny thesis, it was important to include black walnut as the tree species in an

intercropping system because it has been so frequently used and widely studied. A

second species. Norway sprue, a conifer cornmonly planted in windbreaks throughout

the study region. was also included to compare how arthropods respond to different

types of trees within intercropping agroforestry systems.

Arthropods in Agroforestry Systems

In the past, research has conœntrated on tree cultivation and integrating

agroforestry into general agricultural production systems. More recentiy, studies have

focused on biological interactions. such as those including arthropods (Stamps and

Page 33: efek tumpangsari thdp keragaman arthropod

21 Linit, 1998) within temperate agroforestry systems (Gordon et al.. 1997). The theory that

agroforestry systems will provide belter habitat for beneficial arttrropods than

monocultures, and the concerns regarding pests within these two systems, must be

addressed through continued research. This will provide basic knowledge on how to

design agroforestry systems to prevent pest problems from developing and to improve

the action of beneficial arthropods (Rao et al., 2000).

As with agricultural or forest entomology, earfy work on arthropods in

agroforestry systems focused on pests, pnmarily those that attack woody plants in

wind breaks, shelterbelts and hedgerows (Green, 1 906). In addition. some studies

examined agricultural pests that overwinter in windbreaks and hedgerows, such as the

wtton bol1 weevil (Anthonornus grandis grandis Boheman) (Slosser et al., 1984;

Reinhard, 1943).

By the late 1960's. with increasing interest in agricultural ecology, different

aspects of agroecosystems were studied in an attempt to improve food production

(Gliessman, 1990). ldeas regarding the structure of the agricuttural landscape and the

effect that it had on arairopods were developed. It was at this time that hypotheses

regarding vegetational diversity were postulated (e.g. resource concentration,

association resistanœ and natural enemy hypotheses).

Some of the first entomological agroforestry studies were conducted in the

1960's to examine insect flight in association with windbreaks (hedgerows). Lewis

(1965) compared the number of arthropods using agroforestry structures to that in a

neighbouring agricultural crop, and found that the diverse flora of the windbreaks helped

to support a greater abundance of insect species than in the crop field. lnsects

appeared to move between these habitats, thereby enriching communities bordering the

field during the spring and summer (Lewis, 1969a). The beneficial shelter provided by

Page 34: efek tumpangsari thdp keragaman arthropod

22

the windbreaks enhanced insect populations in the field out to a distance of 3-1 0 times

the height of the windbreak on the leeward side and 1-2 times the height on the

windward side (Lewis, 1969a). During windy days (>2.5 k m ) , he found that the density

of flying inseds on the leeward side increased 2-20 times compared to that during days

when the wind was weak (Lewis, 1969b).

Lewis's work also showed that small migrating airbome p s t species, such as

aphids, were in greater abundanœ near the windbreaks than in the field, probably due

to the taller vegetation, which reduced their dispersal. Lewis (1969b) considered that

windbreaks encouraged some pests, but that their populations were more likely to be

controlled by natural enemies near the windbreaks compared to the same pests in the

centre of the field. He also noted that populations of beneficial species decreased

rapidly with increasing distance from the windbreak. Hence he postulated that the

benefits provided by natural enemies were more likely to exert a check on pest

populations in small rather than large fields.

Wfih increasing interest in the science and application of agroforestry, more

agroforestry entomological research has been presented a international conferences

(Huxley (1983) and Rachie (1983) in Epila, 1986) and within agricultural papers

(Matteson et al., 1 984).

Hetempsylla cubana Crawford, a small psyllid native to Central America, was an

important factor in initiating interest in agroforestry entomology. This pest causes

widespread damage to Leucenea spp., a group of agroforestry trees used in the tropics

(Rao et ai., 2000). The psyllid first appeared in Southeast Asia around l98W 1986

(Shelton and Brewbaker, 1994) and was reported in Tanmnia and Kenya in 1992 (Ogol

and Spence, 1997), where a number of important agroforestty research projects were

carried out by the International Center for Research in Agroforestry (ICRAF). Projects

Page 35: efek tumpangsari thdp keragaman arthropod

23 examining the potential of biological control agents for this pest are still ongoing (FAO,

1997; Follett and Roderick, 1 996).

At the same tirne as Heteropsylla was first discovered in Southeast Asia, Epila

(1 986) published a comprehensive paper focusing on agroforestry entomology. Key -

issues, such as the effect of trees in agroforestry systems on arthropod dynamics, as

well as the direction in which entomological agroforestry research needed to be taken,

were addressed. Epila (1986) also started to link the ideas that agroforestry systems

may enhance biological control with nahiral enemies by increasing vegetational

diversity. Most importantly. he pointed out the potential problems of placing trees in

agricuitural systems. For example, oligophagous pests may take advantage of tree

species that are taxonomically related to their target crop pbnts (e.g. trees and crops

that are leguminous)(Rao et al.. 2000). or may use the tees as secondary hosts when

their prefened host is not available. Similarly. pests may become more of a complex

problem in agroforestry systems when perennial plants such as trees are addeâ,

because they allow insect populations to build up over years. Finally, Epila (1986)

pointed out the inherent danger of using non-native introduced plants in agroforestry

systems. because of the increased probability of their being attacked by exotic pests.

In 1988. agroforestry entomology gained international recognition when ICRAF

and the Centre for Applied Biosciences-International (CABI) combined their efforts to

address issues of pest management in agroforestry (Huxley and Greenland, 1989).

Since then, the field of agroforestry entomology has expanded rapidly in the tropics

(Rao et al., 2000; Schroth et al., 2000; Sileshi et al., 2000; Day and Murphy, 1998;

Mchowa and Ngugi, 1994). in the temperate zone (Stamps and Linit, 1998; van Emden,

1998; Vandemeer and Perfecto, 1998; Dix et al., 1997a; Dix et al.. 1995), as well as on

a broader international scale (Dix. 1996; Epila, 1988).

Page 36: efek tumpangsari thdp keragaman arthropod

Over the past decade, the majority of arthropod studies have conœntrated on

windbreaks (sheiterbelts and hedgerows) (Stamps and Linit, 1998) either in Canada

(Holland and Fahrig. 2000). the United States (Dix et al., 1997b; Dix, 1991 ; Dix et al.,

1988; Pasek, l988), England (Maudsley. 2000; Gange and Llewellyn. 1989; Bowden

and Dean, 1977; Lewis. 1972.197Oa. 1 WOb. 1969a. 1969b) or France (Petit and

Bure1.1998). A handful of studies have also examined agroforestry systems with respect

to riparian forest buffets (Snell. 1998; Dix et al.. 1 997a; Mallory, 1993) and silvopasture

systems (Singh and Parihar (1997) in Rao et al., 2000).

Research in intercropping agroforestry systems has also been wnducted more

significantly in the tropics than in the temperate zone. This is because of the common

use of this agricuttural system in the tropics (Nair, 1996). and the la& of a large number

of well-designed intercropping agroforestry plots in the temperate region (Stamps and

Linit, 1999a). Many of the tropical studies concentrate on pest insects that attack trees

in the agroforestry system (Sileshi et al., 2000; Ogol and Spence. 1997; Austin et al.,

1995; Mchowa and Ngugi. 1994). In the tropics, important work comparing arthropod

populations within monoculture and intercropping agroforestry systems (e.g. crop pests

and their natural enemies) has also been conducted (Ogol et al., 1998).

Research by Ogol et al. (1999, 1998) has compared natural enemies of the

maize stem borer (Chilo partellus (Swinhoe)) within a maize monoculture and a maize-

leucaena intercropping agroforestry system in Kenya. They found a greater proporoon

of borer eggs preyed upon in the monoculture field than in the intercropped field.

EggAarval and pupal parasitism within the intercropped system at one site was the

same as in !hc monoculture field. but at other sites. parasitism was higher in the

mono cul tu;^ field than in the neighbouring intercropped field (Ogol et al.. 1998). In

contrast, the numbers of stem borer adults and egg masses were significantly higher in

Page 37: efek tumpangsari thdp keragaman arthropod

25 the monoculhire fields at both locations than in the intercropped system, and this

resulted in higher damage to the maize plants. Since the abundanœ of natural enemies

was equal in both systems, the authors concluded that the difFerenœ in stem borer

populations was a result of resource concentration rather than natural enemies (Ogol et

al., 1999).

In Kenya, Gima et al. (2000) compared pest and beneficial arthropod

populations beside the tree rows and in the crop alley within bean-intercropping and

maize-intercropping agroforestiy sites, using different tree species over several rainy

seasons. They found sig nificantly hig her infestations of beanflies (Ophiomyia spp. ) next

to the tree row (34%) than further out into the crop alley (25%). although there was no

differenœ observed in size of the b a n aphid populations (Aphis fabae Scopoli).

Significantly lower stem borer and maize aphid (Rhopalosiphum maidis (Fitch))

infestations (21 %) were also reported close to the tree rows in the maize intercropped

agroforestry system than further into the crop alley (30% and 32%, respectively), as well

as significant differenœs in natural enemies. Predatory fadybird beetles were

significantly higher in both the bean and corn crop alleyways. while spiders and

hymenopteran populations were significantly higher closer to the tree rows within the

maize intercropped field. There was veiy little discrepancy in arthropod populations

amongst the different tree species used within the tree rows of the intercropped systems

(Gina et al., 2000).

A few studies have examined arthropods in temperate intercropped agroforestry

systems: three from North Arnerica and one from Great Britain. Two of the American

studies have looked specifically at the distribution of predatory carabid beetles within

hardwood black walnut (Juglans nigra L.) and sweetgum (Liquidambar sfyraciflua L.)

systems intercropped with alfalfa and brome, or corn and switchgrass. (Nelson and

Page 38: efek tumpangsari thdp keragaman arthropod

26 Lint, 1999; Ward and Ward, 1999). The other study compared arthropod communities

in a walnut-forage intercropped agroforestry system with arthropod communities in a

monoculture forage field (Stamps et al.. 2000,199913). Using sweep nets, pitfall traps

and vacuum sampling methods, their study found lower numbers of herbivores within

the intercropped systems than in the monoculture system. They also found a

significantly more diverse wmrnunity with a higher ratio between natural enemies and

pests. This research suggests that intercropping agroforestry supports the 'association

resistance" theory in which insect damage is reduced in a vegetationally diverse

cropping system when compared to a single species cropping system.

An intercropped agroforestry system in northem England planted with peas

(Pisum satvium L. cv. Solara) and sycamore maple (Acerpseudoplantanus L.) showed

that the diversity of arthropod taxa was significantly higher in an intercropping alley pea

crop than in a monoculture pea crop (Peng et al., 1993). In this study, the natural enemy

population was 11 % higher in the intercropped alley crops than in the monoculture

crops, with the largest proportion of arthropod pests found in the monoculture system.

The study also found a ratio of natural enemies to pests of 1:1 in the intercropped

alleyway, but 4 :1 in the monoculture area. Evidence from these studies provides dues

as to what can be expected in other ternperate regions.

My research was intended to further Our understanding of arthropod abundance

and divenity for intercropping agroforestry systems in the temperate zone by using a

different collecting technique (i.e. malaise traps). a different crop (i.e. corn). and

different types of tree species (i.e. Norway spruce and black walnut) than have

previously been examined.

Page 39: efek tumpangsari thdp keragaman arthropod

Materials and Methods

Site Description

The study was conducted at the Guelph Field Research Station (43O16'30" N.

89O26.35" W). on the eastem edge of the University of Guelph in southem Ontario,

Canada. Two field sites were used in the study: an intercropping agroforestry field

(University of Guelph Agroforestry Research Station) and an adjacent monoculture crop

field. These fields were located on a drumlin oriented north-south. with an average

dope of 6% and sandy loam soi1 texture. Both fields experienced similar macroclimatic

conditions based on hourly information collected by a weather data logger. The two field

sites were subjected to similar cultivation practiœs (land preparation. pbnting time.

fertiliser rate) and were both zero-ülled (P. Milton. Aberfoyle Agriculture Field Research

Station).

The intercropping agroforestry field was 30 ha in size and was established in

1987. It contained approximately 4.000 deciduous and coniferous trees that were first

planted in the spring of 1998 and 1999, 5-6 m apart along 1 - m- wide rows. The tree

rows were parallel to each other and spaced either 12.5 rn or 15m apart. with crop alley

rows planted in between. The 1 ni-wide tree rows were left fallow and the herbaceous

undergrowth was removed periodically by mowing.

The 24-ha monoculture field was separated from the agroforestry field by a 15-m-

wide roadway and was surrounded by grassy ditches on al! sides. Both the corn (Zea

mays L.) variety (Northup King 2409 in 1999 and Novartis Max 40 in 1998) and crop row

alignment (north-west southeast) were identical to that used in the agroforestry field.

Both fields were pfanted with a corn crop on the same day each year, well before

arthropod sampling began: 1 May 1999 and 28 April 1998.

Page 40: efek tumpangsari thdp keragaman arthropod

Site Selection for Sampling

The agroforestry field was established in 7987 as a split-split plot experimental

design. to test the effects of between-row spacing and crops on the growth of difFerent

tree species (Gordon and Williams. 1991). Because of this, arthropod sampling sites

were selected to standardize the variables examined. The sites were located in tree

rows with a 20 or 30-in-long grouping of 4-5 m tall trees of the same species; either

black walnut (Juglans nigra L.) or Norway spnice (Picea abies (L.) Karst.) and a 15-m

crop alley of the same agncuttural crop (corn) on boai sides of the tree row. Sampling

sites in the monoculture field were selected 30 m away from the edge of the field to

avoid any influence from the surrounding grassy ditches.

1998 Pan Trap Sarnpling

In June 1998. pan traps were used to sample arthropods in the monoculture and

agroforestry fields. Pan traps are shallow pans, which rely on arthropods falling or flying

into a fluid preservative. These traps collect large numben of arthropods living on or

near the ground such as Coleoptera. Collembola. Homoptera and Arachnida. Some

flying insects. such as small Hymenoptera and Diptera. also land in the traps when

canied by the wind (Ausden. 1996; Bio. Sur. Can.. 1994; Martin. 1977). In the

agroforestry field. 5 pan traps were set out in a straight line transect perpendicular to the

tree row at the four selected black walnut and Norway spruce sampling sites. Two pan

traps were placed on either side of the tree row in the crop alley. at a distance of 3.75

and 7.5 m from the centre of the tree row. The fah trap was placed in the centre of the

tree row (Fig. 1 a)). In the monocuîture field. 5 pan traps were set out in the same linear

design in four selected sampling sites (Fig . 1 b)).

Page 41: efek tumpangsari thdp keragaman arthropod

Figure 1. Sampling design used in: a) the intercropping agrofomstry sites with pan traps during June 1998; b) the monoculture site with pan traps during June 1998; c) the intercropping agroforestry sites with malaise taps during June- September 1999; and d) the monoculture site with malaise traps during June- September 1999.

Page 42: efek tumpangsari thdp keragaman arthropod

30

The pan traps were smooth-sided plastic containers, 15 x 15 x 5 cm. They were

placed in the ground with their top edges flush to the soi! suace. All pan traps were %-

filled with a mixture of 4:l water: ethanol to act as a preserving agent. Srnall drops of

liquid Sunlight@ detergent were added to each trap in order to lower the surface tension

of the water. A total of 60 pan traps were placed in the fields on 5 June 1998 for three

sampling days. The collected arthropod sarnpies were placed in g las jars filled with

70% ethanol and retumed to the laboratory for sorting and identification.

1999 Malaise Trap Sampling

Malaise traps (Townes, 1972) were used to sample arthropods in 1999. These

wnsisted of open-sided nylon-mesh tents with a collecting jar on top to intercept flying

arthropods (Sharkey, 1996; Bio. Sur. Can., 1994). The slanted roof of the trap directs

arthropods upwards toward the high point of the trap, into the collecting jar. Malaise

traps are very effective in collecting aduît Diptera, Hymenoptera and some Lepidoptera

(Ausden, 1996; Bio. Sur. Can., 1994; Darling and Packer, 1988; Martin, 1977).

Three sites were sampled monthly dunng 1999; a Norway spruce and a black

walnut site in the agroforestry field, and one site in the monoculture field. The number of

sites was reduced in 1999 compareci to 1998, because of the high cost and labour

required for construction of the traps. which meant only four traps could be used. In

order to sample the three sites thoroughly, the four traps were placed in one site for

three days and then moved to the next site. In the agroforestry field, the traps were set

out with hnro traps in the tree row and two traps within the crop alley on opposite sides of

the tree row. They were al1 spaced 7.5 rn from the centre of the configuration and

aligned vertically to the tree and crop rows (Fig. 1 c)). In the monoculture field, the traps

were set up 30 r n from the field edge in the same shape configuration as in the

Page 43: efek tumpangsari thdp keragaman arthropod

31 agroforestry sites (Fig. 1 d)). The malaise traps were first set out in the Nomay spniœ

site. The collecting jars were %-filleci with a mixture of 4:1= waterethanol to act as a

presenring agent. After remaining in the field for three days, the collecüng jars were

removed from the malaise traps, and the traps were dismantled and moved to the next

site, the monoculture field. This process was repeated three days later, with the traps

being moved to the walnut site and set up as before. All aroiropod samples were placed

in glass jars f i l ld with 70% ethanol and retumed to the laboratory for sorting and

identification.

The traps were set out 20-29 June, 20-29 July, 12-21 August and 19-28

September 1999. A total of 12 malaise samples were collected each month, for an

overall total of 48 samples over the season.

Table 1. Summary of analysis methods and number of samples for each trealment comparison and sampling season.

(Norway spruce of orders site) vs. monocuîture

1998 Pan traps Treatment Analysis method No. of camparisons samples Ag roforestry -Mean abundanœ 40

Norway spmce -Mean abundanœ 40 vs. black walnut of orders

1999 Malaise traps Analysis methoci No. of

samples -Mean abundanœ 32 of orders -Mean abundanœ of functionai trophic groups -Richness and diversity of hymenopteran families

-Mean abundance 32 of orders

Tree row vs. -Mean abundanœ 40 1 crop alley of orders

-Mean abundanœ 32 of orders

Page 44: efek tumpangsari thdp keragaman arthropod

Arthropod Analysis

All arthropods in the pan trap and malaise samples were counted and sorted to

taxonornic Order or Class. depending on the group (e.g. Class for millipedes and

centipedes) using Bomr et al. (1992). Total arthropod abundanœ was then calculateci

for the three sites based on these samples.

Arthropods in different ecologically important functional groups were counted to

be compared between the two agricultural systems. A list was made of 63 arthropod

familieslorders whose primary ecdogical fundion as aduk (larvae only in the case of

Syrphidae) could be categonsed into one of the following trophic gmups: herbivores,

pollinaton, predators. parasitoids and detritivores (Table 2). In cases where taxa were

considered omnivorous or where the familiedorders could be p l a d in more than one

group, attempts were made to select the most appropriate category based on the

predominant function of the taxa members according to the entomological literature

(Goulet and Huber. 1993; Lasalle and Gauld. 1993; Bonor. 1992; McAlpine. 1981 and

Cloudsley-Thompson, 1958). All arthropods from the selected 63 families were further

counted and sorted to taxonomic Family (or Orden) from the 1999 malaise samples

taken from the intercropping agroforestry Norway spruce site and monoculture sites.

Every insect in the order Hymenoptera was identified to family using Goulet and

Huber (1 993) and Borror et al. (1 992); in order to compare family abundance, richness

and divenity within the intercropping agroforestry and monoculture fields.

Page 45: efek tumpangsari thdp keragaman arthropod

Table 2. Selected arthropod families and Order Famiiy Trophic

i

-

Arthropod functional group are summarized

QrouP Hymenoptera Braconidae Parasitoid

-

from Goulet and Huber (1993). LaSalle

lchneumonidae Andrenidae Apidae Colletidae Halictidae Megachilidae Sphecidae Forrnicidae Mutilidae Pompilidae Scoliidae Tiphiidae Vespidae Diapriidae Proctotru pidae Bethylidae Chrysididae Dryinidae Platygastridae Scelionidae Aphelinidae Chalcididae Encyrtidae Eucharitidae Eulophidae Eupelmidae Eurytomidae Mymaridae Pteromalidae Trichogrammatidae Ceraphronidae Megaspilidae Eucoilidae Figitidae Tenthredinidae Elasmidae

Coleoptera Carabidae C hysomelidae Coccinellidae

and Gauld. 1993, Borror et al. (1992), McAlpine (1981) and Cloudsley-Thompson (1 958).

Parasitoid Pollinator Pollinator Pollinator Pollinator Pollinator Predator Predator Predator Predator Parasitoid Parasitoid Predator Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Herbivore Parasitoid Predator Herbivore Predator

their associated functional groups' Order Famiiy Trophic

WOUP Di ptera Asilidae Predator

Dolichopodidae Pipunculidae Syrphidae Tachinidae

Hemiptera Anthocoridae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae Cercopidae Cicadellidae Fufgoroidae

Lepidoptera Noctuidae Pyralidae

Neuroptera Chrysopidae Hemerobiidae

Collernbola Entomobryidae Sminthuridae

Araneae Araneae Opiliones Opiliones Orthoptera Acrididae

Predator Parasitoid Predator Parasitoid Predator Herbivore Herbivore Predator Predator Herbivore Herbivore Herbivore Herbivore Herbivore Herbivore Predator Predator Detritivore Detritivore Predator Detritivore Herbivore

Page 46: efek tumpangsari thdp keragaman arthropod

Data Analysis

Environmental Data

Only 4 malaise traps were availabë during the sampling season in 1999. Thus it

was neœssary to move the traps from site to site every three days in order to collect

within each treatment over roughly the same seasonal period. This provided a total

sampling period of 9 days for each month. Weather conditions were likely to change

over this period. and this in tum could influence sampling success. Because of this. the

weather data was first analysed to determine whether there were significant differenœs

between these in terms of variables that might influence arthropod populations. Weather

data were compared between the three dates for each month using a one-way ANOVA

(Statisitica for Windows. StatSoff Inc. 1998). based on log-transfomed data for relative

humidrty and wind speed. Pair-wise comparisons on the means of each factor were then

done using Tukey's test to determine where the dates were significantly difïerent.

The strength of the relationships between temperature or relative humidity and

their potential influence on arthropod abundance was also analysed. This was

performed using a Pearson product moment coefficient correlation (Statisitica for

Windows. StatSoft Inc. 1998). It was important to identify these relationships because

temperature and humidity can commonly influence arthropod activity. By plotting the

relationship, potential explanations for any differenœs in arthropod abundance could be

presented .

Arairopod Abundance

A non-parametric Wilcoxon normal approximation paired t-test (SAS 6.12, SAS

Institute Inc., 1996) was used to analyse the arthropod abundance data. because they

did not meet the assumption of normality, even after log-transformation. Cornparisons

Page 47: efek tumpangsari thdp keragaman arthropod

were made in mean abundance of the different arthropod orders between: 1) the

intercropping agroforestry and the monoculture treatments; 2) the Nomiay spruce and

black walnut treatments; and 3) the tree rows and crop alleys in the intercropping

agroforestry field. Monthly difFerences in arthropod abundanœ between these . treatments were also detemined for the 1999 sampling season. l Arthropod Functional Group Cornparison (1999 Malaise Traps)

Differences in the abundance of the five arthropod functional groups between the

intercropping agroforestry and the monoculture sites were determined using non-

parametric Wilcoxon normal approximation paired t-tests (SAS 6.12, SAS lnstitute Inc.,

1996). Selected taxa were arranged into functional groups based on the major

ecological roles played by adults in each family.

Ratios between the entomophagous functional groups (Le. predators.

parasitoids) and the herbivore functional group were calculated in order to determine

whether the ecological balance between predaton and prey differed between the

monoculture and intercropped agroforestry sites. This ratio only estimates an ecological

balance because some of the families that would be representatives of these functional

groups may have k e n missed in the selection process, although efforts were made to

pick as many representative families of the predator, herbivore and parasitoid groups as

possible. For each sample, mean sums of the predators and parasitoids were divided by

the mean sums of the herbivores. These ratios were then analysed using non-

parametric Wilcoxon normal approximation paired t-tests (SAS 6.12, SAS lnstitute Inc.,

1 996) to determine differences between the intercropping agroforestry and the

monoculture sites. A low ratio value would indicate a higher level of prey population to

predatortparasitoid population, and thus, possibly a potential disturbance in the balance

Page 48: efek tumpangsari thdp keragaman arthropod

36

of the system. A higher value would suggest that the predatorlparasitoid population was

in better equilibriurn with its prey. I Hymenoptera Richness and Diversity (1999 Malaise Taps)

Hymenopteran farnily richness was wmpared between the intercropping

agroforestry and monoculture treatrnents. Difterences were deterrnined by using the

mean nurnber of families captureci in each sample per treatrnent and then analyzed

using a parametric t-test (Statisitica for Windows, StatSoft Inc. 1998). The divenity of

these families was also detenined using a Shannon diversity index (Hm) (Krebs, f999;

Magurran, 1988). The family diversity was then wmpared between the two field

treatments using a parametric t-test (SAS 6.12, SAS Institute Inc., 1996).

Page 49: efek tumpangsari thdp keragaman arthropod

Resu lts

Annual Environmental Conditions

The 1998 pan trap samples were analysed only for the month of June. Weather

variables for this month differed significantly from the sampling dates in June 1999

(Table 3).

In 1999, different weather conditions may have been experienced by the different

treatments because the 4 malaise traps were placed sequentially in each treatment by

month. m e n the weather variables were m p a r e d between treatments over the four

summer months, the majority did not dmer significantly (Table 3). On two occasions,

however, significant differences were observeci. The first was during September when

rnean temperatures differed between the Nomay spnice and black walnut sites. The

second occurred in June, when relative humidity differed between the Norway spruce

and black walnut sites.

The number of arthropods caught was then related to air temperature (Fig. 2)

and humidity (Fig. 3) at the time of capture. Air temperature had a positive effect on the

nurnber of arthropods caugM (Fig 2). whereas humidity had a negative effect (Fig 3).

Page 50: efek tumpangsari thdp keragaman arthropod

Table 3. Environmenta I data collected from a weather station at the Guelph Agrlcultural Reclearch Station during the summer of 1999. Data based on 3day mean for each month in which malaise ttaps were placed in a given treatrnent

Mean Mean Year Date Treatment Mean air temperature

(C O)(; + SE) Mean relative precipitation windspeed humidity (%) intensity2 - - (mlsec) -

1998 June 5-8 All treaments 10.0620.41" 61.92 21.62* 1.00 2 0.00' 3.75 2 0.17'

1999 June 20-23 Monoculture 21.29t0.96a*3 27.1922.55a 12.70+0.96a 70.7-6.59 ab* 1.1 320.37 a* 0.60fl.25 a* 23-26 Norway spruce 18.8121 .O0 a* 27.1221.22 a 8.3721 .O0 a 62.4421 .46 b 1.00+0.00 a 0.513.22 a* 26-29 Walnut 19.62+3.04 a* 24.562336 a 15.1623.04 a 83.4326.35 a* 1.32+0.7 O a* 0.91+0.65 a*

July 20-23 Monoculture 22.3320.97 a 29.7921.85 a 15.8420.96 a 73.0321 .O1 a 1 .03+0.16 a 7 .11+0.21 a 23-26 Norway spruce 21.8922.15 a 29.2923.07 a 14.6921 .O0 a 67.8523.94 a 1.0920.38 a 0.5820.20 a 26-29 Walnut 21.92fl.63 a 30.0321 .O8 a 13.2223.04 a 66.51g.36 a 1 .04fl.20 a 0.969.28 a

Aug. 12-1 5 Monoculture 18.21+1.98 a 24.0422.03 a 10.9420.96 a 75.63t0.31 a 1 .16+0.47 a 0.92fl.27 a 15-18 Norway spruce 17.5622.65 a 22.80t2.35 a 13.1721 .O0 a 79.67+7.97a 1.01:'O.lla 0.983.37a 18-21 Walnut 19.6220.90 a 20.0322.74 a 1 1.5023.04 a 83.30t6.13 a 1 .12+0.33 a 0.84fl.23 a

Sept. 19-22 Monoculture 11.87+2.01 ab 19.5223.56 ab 3.3720.96 ab 735827.73 a 1.04+0.20 a 0.72%0.40 a 22-25 Nomay spruce 8.88?3.26 b 15.0122.06 b 1.73+1.00 b 76.1 027.40 a 1 .05+0.23 a 0.90+0.26 a 25-28 Walnut 17.5623.77 a 24.43+1.72 a 11.5623.04 a 81 .0321.37 a 1 .O191 1 a 1 .05+0.04 a

' Means followed by an asterisk for June 1998 and 1999 are significantly different at p=0.05 (t-test). Precipitation intensity was ranked into three categories according to Envimnrnent Canada: 1=light (52.5 mmlh), 2=moderate (2.6 to 7.5mmlh) and

3=heavy (3.6 mdh) (Canadian Atmospheric Environmental Services, 1977). Means followed by the same letter in each column within year and month are not significantly different (P50.05, Tukey's test for paired

comparisons)(n=12).

Page 51: efek tumpangsari thdp keragaman arthropod

w

6 8 10 12 14 16 18 20 22 24

3day rnean air temperature (Co)

Figure 2. Relationship between arthropod abundance in malaise traps over a 3- day monthly mean temperature at the Guelph Agricultunl Research station during 1999. (n=l l)(-regression 95% confidence)

Page 52: efek tumpangsari thdp keragaman arthropod

72 76 80

3-day mean relative hurnidity (%)

Figure 3. Relationship between arthropod abundance in malaise traps over a 3- day monthly mean percent relative humidity at the Guelph Agricultural Research station during 1999. (n-1 1) (-regression 95% confidence)

Page 53: efek tumpangsari thdp keragaman arthropod

General Arthropod Abundance

1998 Pan Traps

In June 5-8 1998, a total of 14,272 arthropods where caught by the pan traps.

These were sorted into 15 orders and 2 classes within the phylum Arthropoda. The

majority of the specimens were from the order Collembola (76.14%. N= 10866). while

the Diptera (1 5.22%. N=2172) made up the second largest group. There were 4,526

individuals from 11 orders and 2 classes collected in the pan traps in the corn

monoculture site. The intercropped agroforestry field yielded 3,958 arthropods from the

Norway spruce site and 5.788 from the black walnut site. Samples in both sites

contained representatives of 13 arthropod orden and 2 classes (Appendix 1).

1999 Malaise Traps

During the sampling periods of June. July, August and September 1999, a total

of 32.059 arthropods from 15 orders where caught by the malaise traps. Almost 50% of

the arthropods were from the order Diptera (47.74%. N= 15306). while the

hymenopteran order had the second highest abundance (18.27%. N=5856). The

intercropping agroforestry field yielded the most arthropods. with 13.884 individuals

representing 15 orders caught in the Norway spnice site, and 9,399 arthropods from 14

orders in the black walnut site. Another 8.821 individuals representing 15 orders were

collected from the corn monocuiture site over the same time period (Appendix 2).

Page 54: efek tumpangsari thdp keragaman arthropod

Comparison of Norway Spruce-lntercropping Agroforestry and Conventional Monoculture Systems

1998 Pan laps

The mean abundanœ of arthropods cdlected by the pan traps during 1998

differed significantly between the Nomay spruce-intercropped agroforestry and

monocuiture sites, with a larger number of arthropods caught in the latter (Table 4).

Several significant differences were also found between the treatrnents in terms of

mean abundance of order [e.g. Coieoptera. ûennaptera. Hymenoptera, Opiliones,

Orthoptera and Thysanoptera], with higher mean abundances occumng in the

agroforestry site. Only the order Diptera had a higher mean abundance in the

monoculture than in the intercropped site (Table 4).

1999 Malaise Taps

In 1999, there were no significant differenœs in the mean number of arthropods

captured by Malaise traps between the two treatrnents(Tab1e 5). Similarly, no

significant differences were found between the two treatments in terms of rnean

abundance for many (67%) of the arthropod orders. Exceptions to this were Coleoptera,

Dermaptera. Hymenoptera and Opiliones, which were more abundant in the

intercropped agroforestry than in the monoculture site. Meanwhile. individuals from

order Homoptera were collecteci in the monoculture significantly more than in the

intercropped agroforestry site (Table 5).

Page 55: efek tumpangsari thdp keragaman arthropod

Table 4. Mean abundance of arthropod orden collected in pan traps over a 3day period from a corn intercropped agroforestry site and a monoculture site at the Guelph Agricultural Research Station, 5-8 June 1988 (N=40).

Arthropod orders Mean no. arthropodsltrap

Monoculture Ag rofo rest ry z ' P

Araneae Chitopoda Coleoptera Collembola Dermaptera Diplopocla Diptera Hemiptera Homoptera Hymenoptera lsopoda Lepidoptera Odonata Opiliones Orthoptera Thysanoptera

All orders 14.02 2 2.66 9.94 + 2.84 -3.1 1 <0.01 *

' Wilcoxon two sample test, one-sided Pr < Z , df= 19. * Wilcoxon two sample test, one-sided Pr c Z ,df =360.

Significantly different p20.05.

Page 56: efek tumpangsari thdp keragaman arthropod
Page 57: efek tumpangsari thdp keragaman arthropod

While no significant differenœs were observed in the overall rnean number of

arthropods collecteci from the intercropped or monoculture sites (Table 5). differences

were observed for individual arthropod orders in specific months (Table 6). During June.

Coleoptera, Collembola, Hymenoptera and Orthoptera were al1 significantly more

abundant in the intercropped than the monoculture site. while significantly more

homopterans were found in the monoculture than in the intercropped site. Lepidoptera

in July and. plus Neuroptera and Coleoptera in August were al1 found to be significantly

more abundant in the intercropped than in the monoculture site. During September.

Diptera and Hemiptera were more abundant in the monoculture than in the intercropped

site (Table 6).

Page 58: efek tumpangsari thdp keragaman arthropod

Table 6. Mean abundance of arthropod orders collected in malaise traps over a 3- day period from a corn intercropped agrofommtry site or a monoculture site at the Guelph Agriculairal Research Station, JuneSeptember 1999 (N=32).

Month Arthropod Mean no. arthropodsitrap order (; + SE)

Monocuiture Ag roforestry 2 ' P I

June Araneae Coleoptera Collembola Demiaptera Diptera Hemiptera Hornoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orden * July Araneae

Coleoptera Collembola Dennaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders

0.34 0.03 * 0.05 * 0.10 0.08 0.29 0.03 ' 0.03 ' 0.34 0.17 0.50 0.06 0.05 * 0.23 0.09

0.23

0.39 0.12 0.44 O.? 1 0.17 0.12 0.34 0.08 0.03 0.09 0.24 0.44 0.44 0.37 0.39

0.34

Cont.

Page 59: efek tumpangsari thdp keragaman arthropod

September

Coleoptera Collem bola Dermaptera Diptera Hemiptera Homaptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

Table 6 (cont.) Month Arthropod Mean no. arthropodslhap

order (; +SE) Monoculture Ag roforestry Z' P

August Araneae 3.50 1.44 2.00 + 0.41 0.88 0.20 39.75 + 3.77 93.50 + 13.91 -2.17 0.03

All orders

Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders

' Wilcoxon two sample test. one-sided PrcZ, d e 3 . Wilcoxon two sample test. one-sided PrcZ ,dC7 1 . ' Significantly different p50.05.

Page 60: efek tumpangsari thdp keragaman arthropod

Functional Arthropod Groups and Selected FamilieslOrdem from 1999 Malaise Tram

Approximately haif of the arthropoâs caught in the Norway spruce and corn

monoculture sites were sorted into a pre-selected group of 61 families and 2 orders

(Araneae and Opiliones). These represented five functional trophic groups; detritivores.

herbivores, parasitoids. predators and pollinators. In total, II ,202 individuals arthrapods

were sorted, with 7,005 from 60 families and 2 orders in the Norway spruce-

intercropped agroforestry site. and 4,197 individuals from 55 families and 2 orden in the

corn monocutture site.

The family with the largest number of arthropods from the selected group was

Entomobryidae (Collembola) (25.8% of the abundanœ of al1 selected families, N=2895),

representatives of the detritivore group. The most abundant herbivore family was

Aphidae (N= 1108), followed in desœnding order by the most abundant parasitoid

Scelionidae (N= 664). predator Coccinellidae (N-98) and pollinator Halididae (N=82)

families (Appendix 3).

Of these five trophic groups. only two differed significantly between the two

treatments (Table 7). Both detritivores and parasitoids were significantly more abundant

in the intercropped than in the monoculture site.

Page 61: efek tumpangsari thdp keragaman arthropod

Table 7. Arthropod abundance by functional groups from malaise traps opeating for 3-day periods in a corn monocultum and an intercropped corn site at the Guelph Agriculture Research Station, Ontario, June-September 1999 (N32).

Functional groups Mean no./ trap(x +SE) d f 2' P

Monoculture Ag roforestry

Detritivore 8.352 2.13 59.69 + 25.17 47 -1.84 0.03 ' Herbivore 8.912 2.50 5.21 + 1.16 175 -0.87 0.19 Parasitoid 2.502 0.33 4.49 + 0.48 447 -4.40 e0.01 Pollinator 0.532 0.14 0.91 1' 0.30 79 -0.90 0.19 Predator 4.162 0.59 4.45 + 0.48 255 -1.42 0.08

' Wilcoxon two sample test. one-sidd PrcZ. ' Significantly different p50.05.

Monthly differenœs between the functional groups in the two treatments were

also apparent. The abundance of parasitoids was significantly higher in the intercropped

site than in the monocultute site during June and July. In September. however. there

were significantly more parasitoids in the monoculture field than in the intercropping

site. Detritivores were signifcantly higher in the intercropped site during June while

predators were higher during August (Table 8).

No overall difference was found in the ratio of predators to herbivores between

the monoculture and the agroforestry treatments, but significant differences were seen

for the ratio of parasitoids to herbivores. June was the only month in which the

agroforestry treatment had a significantly higher ratio of both predators and parasitoids

to herbivores. In July, only the ratio between parasitoids and herbivores was

significantly higher (Table 9).

Page 62: efek tumpangsari thdp keragaman arthropod

Table 8. Abundance of arthropods by functional groups from malaise traps placed three days each month in a corn intercropped agroforestry rite and a corn monoculture site at the Guelph Agricultural Research Station, June- September 1999 (N=32).

Month Functional Mean no. arthropodsltrap - groups ( X -E)

Monoculture Ag roforestry d f 2' P

June Detritivore Herbivore Parasitoid Pollinator Predator

July Detritivore Herbivore Parasitoid Pollinator Predator

August Detritivore Herbivore Parasitoid Pollinator Predator

September Detritivore Herbivore Parasitoid Pollinator Predator

' Wilcoxon h o sample test, one-sided Pr*Z * Significantly different p50.05.

Page 63: efek tumpangsari thdp keragaman arthropod

Table 9. Mean ratio between the number of predatom or pararitoids and herbivores collected over three days using malaise traps in a corn monoculture site and a intercropped agroforertry site at the Guelph Agriculture Research Station, Ontario, June-September tg99 (N=32).

Functional group Mont h Monoculture Agroforestry d f 1' P ratios (X +SE) (i +SE)

Predators: herbivores

Parasitoids: herbivores

June July August September

Overall

June Jul y August Septem ber

Overall

'~aired sample t test. * Significantly different p50.05.

Page 64: efek tumpangsari thdp keragaman arthropod

In alrnost one quarter of the 63 selected taxa (representing the five fundional

trophic groups) mean arthropod abundance was significantly higher in the intercropped

site than in the monoculture site (Table 1 O). One of these families was the Opiliones,

representing the detritivore fundional group, was found be significantly different

between the two treatrnents. In addition, 8 out of 28 selected parasitoid families (29%)

had a mean abundance significantly higher in the intercropped site than in the

monocuiture site. These parasitoid families included, Aphelinidae, Chalcididae,

Diapnidae , Encyrtidae, Euwilidae, Eupelmidae, lchneumonidae and Platygastridae. A

similar percentage of predaceous families (5 out of 17 or 29% of the selected predator

families) also had significantly difFerent mean abundances between the two treatments.

Four of these predaceous families. the Carabidae, Pompilidae, Sphecidae, and the

Chrysopidae, were signficantly more abundant in the intercropped site than in the

monoculture site. The Anthocoridae and Cidadellidae familes, representing the

predators and herbivores respectively. were found to have significantly higher means in

the monoculture site than in the intercropped site.

Page 65: efek tumpangsari thdp keragaman arthropod

Table 10. Mean abundance of arthropod kmiliedorders in malaise trop over a 3- day period from a corn intercropped agroforestry site and a corn monoculture site at the Guelph Agricultural Research Station, JuneSeptember 1999 (N=32).

Arthropoâ ANiropod Funciional Mean no. arthropodsltrap order familieslorden group (; +SE)

Monocutture Agroforestry 2' P

Araneae Araneae Coleoptera Carabidae

Chysomelidae Coccinellidae

Collembola Entomobryidae

Sminthuridae Diptera Asilidae

Dolichopodidae Pipunculidae Syrp hidae Tachinidae

Hemiptera Anthocoridae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae Cercopidae Cicadellidae Fulgoroidae

Hymenoptera Andrenidae Aphelinidae Apidae Bethylidae Braconidae Ceraphronidae Chalcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae Eulophidae Eupelmidae Eurytornidae Figitidae Forrnicidae

Preâator Predator Herbivore Predator Detritivore

ûetritivore Predator Predator Parasitoid Predator Parasitoid Predator Herbivore Herbivore Predator Predator Herbivore Herbivore Herbivore Herbivore Pollinator Parasitoid Pollinator Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Pollinator Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Predator

Page 66: efek tumpangsari thdp keragaman arthropod

Table 10 (wnt.) Arthropod Arthropod Fundional Mean no. arthropods/trap

order familieslorders group (X +SE) Monocuiture Agroforestry Z' P

Hymenoptera Halictidae lchneumonidae Megachilidae Megaspilidae Mutilidae Mymaridae Platygastridae Pompilidae Proctotrupidae Pteromalidae Scelionidae Scoliidae Sphecidae Tenthredinidae Ti phiidae Trichogramrnatidae Vespidae

Lepidoptera Noctuidae Pyralidae

Neuroptera Chrysopidae Hemerobiidae

Opiliones Opiliones Orthoptera Acrididae

Pollinator Parasitoid Pollinator Parasitoid Predator Parasitoid Parasitoid Predator Parasitoid Parasitoid Parasitoid Parasitoid Predator Herbivore Parasitoid Parasitoid Predator Herbivore Herbivore Predator Predator Detritivore Herbivore

' Wilcoxon two sample test. one-sided PrcZ, dft l5. * Significantly different ~50 .05 .

Several representative families differed significantly between the treatrnents in

terms of mean abundance by month (Table II). In June. 9 hymenopteran families and 1

family from each of the Coleoptera, Collembola, Diptera, Homoptera and Orthoptera

orders, differed significantly between the treatments. In July, only 10 families differed

significantly, while in August, only 6 families differed. In September, the abundance of 7

families were significantly different, al1 of them having higher mean abundance in the

corn monoculture site than in the intercropped site, except for lchneumonidae which

had a higher significant abundance in the intercropped site.

Page 67: efek tumpangsari thdp keragaman arthropod

Table 11. Mean monthly abundanœ of selectsd arthropod familieslorden, collecteû in malaise tram over a 3day period from a corn intercropped agrofotestry sita and a corn monoculture site at the Guelph Agiicuttural Research Station, JuneSeptember 1999 (N32).

Month Order Arthropod familieslorders

June Araneae Araneae Coleoptera Carabidae

Chysomelidae Coccinellidae

Collem bola Entomobryidae Sminthuridae

Diptera Asilidae Dolichopodidae Pipunculidae Syrphidae Tachinidae

Hemiptera Anthocofidae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae Cercopidae Cicadellidae Fulgoroidae

Hymenoptera Andrenidae Aphelinidae Apidae Bethylidae Braconidae Ceraphronidae C halcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae Eulophidae Eupelmidae Eurytomidae Figitidae

Mean no. arthropodsîlrap ( Z ?SE)

Monoculture Aclroforestrv

Page 68: efek tumpangsari thdp keragaman arthropod

Table 11 (cont.)

Month Order Arthropod Mean no. arthropoâs/trap familieslorders (G ?SE)

Monoculture Agroforestry

June Hymenoptera Fomicidae Halictidae lchneumonidae Megachilidae Megaspilidae Mutilidae M ymaridae Platygastridae Porn pilidae Proctotrupidae Pteromalidae Scelionidae Scoliidae Sphecidae Tenthredinidae Tiphiidae Trichogrammatidae Vespidae

Lepidoptera Noctuidae Pyralidae

Neuroptera Chrysopidae Hemerobiidae

Opiliones Opiliones Orthoptera Acrididae

July Araneae Araneae Coleoptera Carabidae

Chysomelidae Coccinellidae

Collembola Entomobryidae Sminthuridae

Diptera Asilidae Dolichopodidae Pipunculidae S yrphidae Tachinidae

Hemiptera Anthocoridae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae Cercopidae Cicadellidae

0.39 O. 37 0.04 * 0.03 ' 0.50 0.44 0.08 0.29 0.05 * 0.50 0.17 O. 34 0.50 0.50 0.14 0.24 O. 34 0.28 0.34 cont.

Page 69: efek tumpangsari thdp keragaman arthropod

Table 11 (cont.)

Month Order Arthropod Mean no. arthropoddtrap familiedo rders (s +-SE)

Monoculture Agroforestry Z' P

July Homoptera Fulgoroidae Hymenoptera Andrenidae

Aphelinidae Apidae Bethylidae Braconidae Ceraphronidae Chalcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae Eulophidae Eupelmidae Eurytomidae Figitidae Formicidae Halictidae lchneumonidae Megachilidae Megaspilidae Mutilidae Mymaridae Platygastridae Pompilidae Proctotrupidae Pteromalidae Scelionidae Scoliidae Sphecidae Tent hredinidae Tiphiidae Trichogrammatidae 2.25 + 1.32 Vespidae 1.25 + 0.75

Lepidoptera Noctuidae 1.00 2 0.58 Pyralidae 0.00 + 0.00

Neuroptera Chsrçopidae 1.50 2 0.65 Hemerobiidae 2.752 0.48

Opiliones Opiliones 1.00 +. 0.41 cont.

Page 70: efek tumpangsari thdp keragaman arthropod

58 Table 11 (cont.)

Month Order Arth ropod Mean no. arthropodshrap familieslorders (x S E )

Monocuttute Agroforestry 2' P

July Orthoptera Acrididae August Araneae Araneae

Coleoptera Carabidae C hysomelidae Coccinellidae

Collembola Entomobryidae Sminthuridae

Diptera Asilidae Dolichopodidae Pipunculidae Syrphidae Tachinidae

Hemiptera Anthocoridae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae Cermpidae Cicadellidae Fulgoroidae

Hymenoptera Andrenidae Aphelinidae Apidae Bethylidae Braconidae Ceraphronidae Chatcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae Eulophidae Eupelmidae Eurytomidae Figitidae Forrnicidae Halictidae lchneumonidae Megachilidae

0.44 0.20 0.13 0.17 0.03 ' 0.05 * 0.44 0.1 t 0.44 0.44 0.44 0.1 1 0.17 0.50 O. 17 O. 50 O. 50 o. 50 0.05 ' 0.29 0.25 0.31 0.1 1 0.24 0.1 1 0.04 ' 0.50 0.50 0.50 0.50 0.17 0.14 0.50 0.20 O. 50 0.14 0.29 0.1 1 0.50 0.50 0.39 0.24 0.03 ' 0.50

cont.

Page 71: efek tumpangsari thdp keragaman arthropod

Table 7 1 (cont. )

Month Order Arthmpod Mean no. arthropodskap familiedorders (2 ?SE)

Monoculture Agroforestry

August Hymenoptera Megaspilidae 1.50 2 Mutilidae 3.00 2 M ymaridae 22.25 2 Platygastridae 0.25 2 Pompilidae 6.25 2 Proctotni pidae 0.00 2 Pteromalidae 3.75 5 Scelionidae 36.50 2 Scoliidae 0.00 2 Sphecidae 1 .O0 2 Tenthredinidae 0.00 2 Tiphiidae 0.25 2 Trichogrammatidae 0.50 2 Vespidae 0.25 2

Lepidoptera Noctuidae 0.50 2 Pyralidae 1.50 2

Neuroptera Chrysopidae 0.00 -, Hemerobiidae 0.25 2

Opiliones Opiliones 0.00 5 Orthoptera Acrididae 0.25 -,

Sept. Araneae Araneae Coleoptera Carabidae

Chysomelidae Coccinellidae

Collembola Entornobryidae Sminthuridae

Diptera Asilidae Dolichopodidae Pipunculidae Syrphidae Tachinidae

Hemiptera Anthocoridae Lygaeidae Miridae Nabidae Reduviidae

Homoptera Aphidae

Cercopidae Cicadellidae Fulgoroidae

Hymenoptera Andrenidae Aphelinidae Apidae

0.50 0.03 " 0.32 0.50 0.50 0.04 ' cont .

Page 72: efek tumpangsari thdp keragaman arthropod

Month Order Arth ropod Mean no. arthropodshrap familiedorders ( G %SE)

Monoculture Agroforestry Z' P

Sept. Hymenoptera Bethylidae Braconidae Ceraphronidae Chalcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae Eulophidae Eupelmidae Euryîomidae Figitidae Fomiicidae Halictidae lchneumonidae Megachilidae Megaspilidae Mutilidae Mymaridae Platygastridae Pompilidae Proctotrupidae Pteromalidae Scelionidae Scoliidae Sphecidae Tenthredinidae Ti phiidae Trichogrammatidae ~espidae 10.00 2 2.38

Lepidoptera Noctuidae 0.25 + 0.25 Pyralidae 0.00 + 0.00

Neuroptera Chrysopidae 0.25 + 0.25 Hemerobiidae 0.00 +. 0.00

Opiliones Opiliones 0.00 + 0.00 Orthoptera Acrididae 0.00 2 0.00

'-Wilcoxon two sample test, one-sided Pr<Z, df= 3. ' Significantly different ~50 .05 .

Page 73: efek tumpangsari thdp keragaman arthropod

Hymenoptenn Family Richness and Diversity from 1999 Malaise Trape

The order Hymenoptera was represented by 37 different families in samples

collected during June-September 1999. In the intercropped site, 36 families were found

while only 30 families were wllected in the corn monocuiture site. In ternis of family

richness, there were no significant difFerences between the mean number of families in

the intercropped and the wm monoculture sites. Sig nificant differences were observed.

however, during June and July (Table12).

Table 12. Mean number of hymenopteran families in malaise tmps from an intercropped agroforestry site and a corn monoculture site al the Guelph Agricultural Research Station, June-September 1999 (N=32).

Month Mean no. hymenopteran familiesltrap (i ?SE)

t ' df P Monoculture Ag roforestry

June 9.50 + 0.87 18.75 + 0.85 -7.61 3 eO.01 * JuSc 17.75 + 1.31 24.75 + 1.25 -3.86 3 e0.01 * A U ~ U S ~ 15.25 5 2.50 17.75 + 2.36 -0.73 3 0.49 September 11.75 + 1.49 8.25 + 1.18 1.84 3 0.12

Atl season 13.56 + 1.10 17.38 + 1.67 -1.90 15 0.07

' Paired sample t test. * Significantly different ~50.05 .

The Shannon diversity index for diversrty of hymenopteran families in the

intercropped site was H'=2.81, while it was H'=2.73 for corn monocuiture site. No

significant difference was found between these indices for either treatment (t=1.12.

Page 74: efek tumpangsari thdp keragaman arthropod

Cornparison of Norway Spruce and Black Walnut in the lntercropping Agroforestry System

1998 Pan Traps

Mean arthropod abundance between the black walnut and the Norway spruce

sites was not significantly dflerent in 1998 (Table 13). There were also no significant

differenœs among rnost of the taxonornic groups between the black walnut and Norway

spruce sites, exœpt for Araneae and Coleoptera, both which had higher mean

abundances in black walnut than Nomay spnice site, and Lepidoptera which was

higher in the Norway spruce site than the black walnut site (Table 13).

1999 Malaise Traps

Arthropod abundanœ differed significantly between the black walnut and the

Norway spruce sites (Table 14). Several orden were also significantly more abundant in

the Norway spruce site and none of the orders were significantly different in the black

walnut sites. These orders included; Araneae, Dermaptera, Hemiptera, Orthoptera,

Psowptera and Thysanoptera (Table 14).

Page 75: efek tumpangsari thdp keragaman arthropod

Table 13. Mean abundance of arüiropod orders collected for three dayr using pan ûaps in sites either intercropped wlth Nowuay spruce or black walnut at the Guelph Agriculture Research Station, 5-8 June 1998 (N=40).

Arthropod orders Mean no. arthropodsltrap -

(x +-SE)

Noway spruce Black walnut z' P

Araneae C hilopoda Coleoptera Collembola Dermapte ra Diplopoda Diptera Hemiptera Homoptera Hymenoptera lsopoda Lepidoptera Opiliones Orthoptera Psocoptera Thysanoptera

All orders 10.452 2.99 15.31 + 3.38

Wilcoxon two sample test, one-sided Pr < Z , df= 1 9. * Wilcoxon two sample test, one-sided Pr < 2, df=360. * Significantly different p0.05.

Page 76: efek tumpangsari thdp keragaman arthropod

Table 14. Mean abundance of arthropod orders collecbd for three days uring pan ûaps in sites either inbrcropped with Nomay spruce or black walnut at the Guelph Agriculture Research Station, June-September 1888 (N=32).

Arthropod orders Mean no. arthropodsltrap (i +SE)

Nonnray spruce Black walnut 2' P

Araneae Coleoptera Collembola Demaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders2 48.21 + 8.61 32.64 + 4.89

' Wilcoxon two sample test, one-sided Pr < Z , df= 15. * Wilcoxon two sample test, one-sided Pr < Z , dF287. ' Significantly different p50.05.

Page 77: efek tumpangsari thdp keragaman arthropod

Mean arthropod abundance differed significantly between the two intercropped

treatments during June, July and August, but not during September (Table 15). In June,

4 arthropod order, Coleoptera, Diptera, Hemiptera and Orthoptera were signifmntly

more abundant in the Norway spnice site, while in the same month Neuroptera had was

signficant more abundant in the black walnut site. Two orden were significantly greater

in the spnice site than the walnut site during July (Araneae and Hemiptera), as well as

two in August (Coleoptera and Neuroptera). In September, arthropod abundanœ of

both Coleoptera and Diptera was higher in the black walnut site than in the Notway

spruce site (Table 15).

Page 78: efek tumpangsari thdp keragaman arthropod

Table 15. Mean monthly abundance of arthropoâ orders collected for three days using pan traps in si- either intercropped with Norway spruce or black walnut at the Guelph Agriculture Research Station, June-Septamber 1999 (N=32).

Month Arthropod Order

June Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders

Juiy Araneae Coleoptera Collembola Demiaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders

Mean no. arthropodsfirap - ( X +SE)

Noway Spnice Walnut

cont.

Page 79: efek tumpangsari thdp keragaman arthropod

Tabîe 15 (cent.)

Month Arthropod Mean no. arthropodsltrap order (; LSE)

Norway Spruce Walnut August Araneae 2.00 + 0.41 1.75 2 1.44

Coleoptera Collembola Dermaptera Diptera Hemi ptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocopte ra Thysanoptera

All orders 42.99 2 10.49 21.99 + 6.90

September Araneae Coleoptera Collembola Demaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders 9.71 + 3.11 31.21 + 10.11

Wilcoxon two sarnple test, one-sided Pr< Z, d t 3 Wilcoxon two sample test, one-sided Pr< 2, df=71

* Significantly different p50.05.

Page 80: efek tumpangsari thdp keragaman arthropod

Cornparison of Tree Rows and Crop Alleys in the lntercropping Agroforestry System

1998 Pan Traps

Overall arthropod abundance differed significantly between the tree rows and the

crop alleys in the Norway spnice intercropped site during 1998 (Table16). For the

majority of the taxonomic groups, however no significant difFerences were seen

between the tree row and crop alley, with the exception of Chilopoda, Diplopoda,

Hemiptera and Opiliones (Table 16).

In the Norway spruce site, there were four arthropod orders/cIasses that had

significantly higher means in the tree row than the crop alley; Chilipoda, Diplopoda.

Hemiptera and Opiliones. In the black walnut site, only the Homoptera order had a

significantly higher mean in the crop alley, while four ordenlclasses had significantly

higher means in the tree row, Coleoptera, Collembola. Diplopoda, Diptera, and

Homoptera (Table 17).

1999 Malaise Tnps

No significant differences were observed in the mean number of arthropods

between the tree row or crop alley in the intercropping agroforestry sites (Table 18).

Similarly, no differences were observed between the tree rows and the crop alleys in the

abundance of various arthropod taxonomic groups, with the exception of Homoptera,

which was signficantly higher in the crop alley than the tree row (Table 18).

There was also no significant difference between these two habitats during June,

July or Aug ust, althoug h during September sig nificantly more arthropods were collected

in the tree row than in the crop alley (Table 19). Similarly, no significant differences

were observed between the tree row and the crop alley for the different arthropod

Page 81: efek tumpangsari thdp keragaman arthropod

orders in any of the four months, with the exception of Diptera in August and

Collembola. Homoptera and Neuroptera in September (Table 19).

For the individual tree species sites, none of the orders differed significantly

between the tree row and crop alley for the Nomay spruce site, while in the black

walnut site, only Homoptera showed a significant difference between the two locations

(Table 20). Here the mean abundance of homopterans was greater in the crop alley

than the tree row.

Page 82: efek tumpangsari thdp keragaman arthropod

Table 16. Mean abundance of arthropod orden collected in pan ûaps over a 3day period in tree rows and crop alleys of sites in the intercropping agroforestry site at the Guelph Agricultural Research Station, 5 8 June 1998 (n=40).

Arthropod orden Mean no. arthropodsltrap (; +SE)

Tree row Crop alley 2' P

Araneae C hilopoda Coleoptera Collembola Demaptera Diplopoda Diptera Hemiptera Homoptera Hymenoptera lsopoda Lepidoptera Opiliones Orthoptera Thysanoptera

All ordersb 1.80 + 0.20

1 W~lcoxon h o sample test, one-sided Pr < Z, df= 19. 2 W~lcoxon two sample test, one-sided Pr * 2, df= 399. * Significantly different p50.05.

Page 83: efek tumpangsari thdp keragaman arthropod

Table 17. Mean abundance of arthropod orden collected in pan traps over a 3day period in either the ûee rows or crop allsys in the Nomay spruce and black walnut treatments of lntercropping agroforestty site at the Guelph Agricultural Research Station, during 5 8 Juns 1998 (n=40).

Arthropod Mean no. arthropodshap Mean no. arthropodsltrap ordets (; +SE)

Norway spruce 2' P (i +-SE)

Black walnut Tree row Crop alley Tree row Crop alley

Araneae C hilopoda Coleoptera Collembola Derrnaptera Diplopoda Diptera Hemiptera Homoptera Hymenoptera lsopoda Lepidoptera Opiliones Orthoptera Psocoptera Thysanoptera

' Wilcoxon two sample test, one-sided Pr * Z , df= 9. Significantly different ~50.05.

Page 84: efek tumpangsari thdp keragaman arthropod

Table 18. Mean abundance of arthropod orders collected in Malaise traps over a 3day period in tree rom, and crop alleys in the intercropping agroforestry site at the Guelph Agricultural Research Station, during JuneSeptember 1999 (n=32).

Arthropod orders Mean no. arthropodsllrap

Tree row Crop alley

Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders2 36.87 + 6.89 43.97 + ' Wilcoxon two sample test, one-sided Pr < Z , df= 15. * Wilcoxon two sample test, one-sided Pr < Z , df= 287. * Significantly different p50.05.

Page 85: efek tumpangsari thdp keragaman arthropod

73 Table 19. Mean monthly abundance of aithropod orciers collected in Malaise tmps over a 3-day priod the tiee mws and cmp alleys in the indemropping agrofomstry site at the Guelph Agriculturol Research Station, during June- September 1999 (n=32).

Month Arthropod Mean no. arthropodsltrap order ( i ?SE)

z' P Tree row Crop alley

June Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

All orders2

July Araneae Coleoptera Collembola ûemiaptera Diptera Hem iptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Th ysanoptera

AH orders

cont.

Page 86: efek tumpangsari thdp keragaman arthropod

Table 19 (cont.)

Month Arthropod Mean no. arthropodsltrap orcîer (X -E)

Tree row C r o ~ allev

August Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

AI1 orders 20.07 5 4.75 44.90 2 11.57

September Araneae Coleoptera Collem bola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Ort hoptera Psocoptera Th ysanoptera

All orders 11.24 4 4.67 29.68 +. 9.53

' Wtlcoxon two sample test. one-sided Pr< Z,df=3. Wilcoxon two sample test. one-sided P r Z,df=71 Significantly different p50.05

Page 87: efek tumpangsari thdp keragaman arthropod

Table 20. Msan abundance of arthropod orders collected in pan traps over a 3day period in the h e rom, or crop alleyr of sites intercropped with either Norway spruce and black walnut in the lntercropping agroforestry field at the Guelph Agricultural Research Station, during June-September 1989 (N-32).

Arthropod orders Mean no. arthropodsltrap -

(X +SE) Norway spruce 2' P

Tree row Crop alley

Araneae Coleoptera Collembola Dermaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Psocoptera Thysanoptera

Mean no. arthropodshrap (; +SE)

Black walnut 2' Tree row Crop alley

Wilcoxon two sample test, one-sided Pr< Z,df=7. ' Significantly different p50.05

Page 88: efek tumpangsari thdp keragaman arthropod

Discussion

Environmental Conditions During 1999

Many abiotic factors influence arthropod population dynamics, one of the most

important being weather. Temperature and humidity are two well-known climatic

elements that affect activity and behaviour of these poikilothermic organisms (Weisser

et al., 1997). Optimal temperature thresholds for arthropod activity generally occur

between 10-35OC, aithough many arthropods, such as moths, can fiy when the air

temperature is close to 0°C (Schowalter, 2000; Chapman, 1998). The influence of

humidity on arthropod adivity is atso important, but is generally less pronounœd than

that of temperature (Stein, 1 986).

Families of insects react in different ways to changes in these two weather

variables. For instance, one study examining activity of hymenopteran parasitoids found

that ichneumonids preferred temperatures between 15-21 OC, while braconiâs preferred

temperatures q 21 -7OC. Populations of both these insects decreased when the relative

humidity was < 25% or > 90% (Juillet, 1964). My resuîts are similar to those of Juillet

(1 964, 1960) for parasitic Hymenoptera, showing a positive population response with

temperature but a negative relationship with humidtty.

Given the significant effect of air temperature on arthropod populations, the

Nomay spnice data from September should be regarded cautiously. When this site was

sampled, the mean 3day air temperature dropped below 1 O°C, the commonly accepted

temperature threshold for arthropod activity (Chapman, 1998). Cornpansons between

this site and the black walnut site, or between the monocuiture and intercropped

Page 89: efek tumpangsari thdp keragaman arthropod

agroforestry treatments during September, therefore. may sirnpîy be a result of

differenœs in air temperature between the two sample dates.

Similarly, dunng June 1999, relative humidity levels differed between the Norway

spruce and black walnut sampling dates. This means that the significantly higher

numbers of arthropods found in the Norway spruce site could simply be a result of a

difference in relative humidity. The fact that there were no signkant differenœs

between humidity levels during July and August, and the mean number of arthropods

was still higher in Norway spruce than black walnut. suggests that dmerenœs in relative

humidity do not explain the treatment effeds in June. Relative humidity for the two June

dates was also well within the maximum and minimum thresholds set by Juillet (1964)

for Hymenoptera.

Cornparison of lntercropping Agroforestry and Conventional Monoculture Systems

Intercropping rows of trees within a corn crop did not appear to affect the overall

number of arthropods in the agroecosystem, because both the conventional

monoculture and the agroforestry fields had similar densities. This was consistent

across al1 four sampling months in 1999. These findings contrast those of Stamps et al.

(2000) who found significantly higher amounts of arthropods in the monoculture field.

During June 1998, however, there were significantly greater numben of arthropods

coilected in the corn monocutture than in the intercropped agroforestry treatment. This

discrepancy between the 1999 and 1998 results could be due to the different types of

sampling methods used (pan traps for ground arthropods in 1998 versus malaise traps

for aerial arthropods in 1999). If this is correct. then the significant difference between

the two fields in 1998 should be reflected in the number of grounddwelling arthropods

caught in the monoculture and the agroforestry treatments. As none of the primarily

Page 90: efek tumpangsari thdp keragaman arthropod

78 grounddwelling arairopoâs (e.g. Chilopoda, Diplopoda, or Isopoda) differed between

the two sites, it is unlikely that the trapping method affecteci the results. Moreover. al1 of

the other taxonomie orden that were significantly different between the two fields in

1998 were also different in June 1999, as well as over the entire season of 1999 (e.g.

Coleoptera. Hymenoptera and Orthoptera). Thus. the discrepancy between the 1999

and June 1998 data is more likely due to the substantially higher number of Diptera

collected during 1998 in the monoculture field.

Although the overall abundanœ of arthropod individuals did not Vary between the

intercropping agroforestry and monoaiiture treatments, this does not provide sufficient

information to perform an accurate assessment of ecological sustainability. Diversity,

taxa richness, and relationships among functional groups are better indicators for

performing such an assessment (Paoletti, 1999; Letoumeau, 1998; Swift et al., 1996;

Altiefi. 1991).

Numerous arthropod orders and families were more abundant in the

intercropping agroforestry field than in the monoculture field. In addition. almost ail of

the orders that were significantly different in the 1999 Malaise traps, were also different

in the 1998 pan traps. Orders that were different included: Coleoptera. Demaptera,

Opiliones and Hymenoptera.

Coleoptera is the second largest arthropod order in Canada in terms of number

of species (Danks, 1988). and its members belong to several different trophic groups.

including herbivores, predators, and detritivores (Lawrence, 1991). The majonty of the

beetles in the monoculture field (71 56) were members of three families (Carabidae,

Chrysomelidae and Coccinellidae). In contrast, these famiiies represented only 43% of

the beetles collected in the agroforestry field. This suggests that the agroforestry site

supported a greater divenity of Coleoptera. This may have been due to an increased

Page 91: efek tumpangsari thdp keragaman arthropod

number of microhabitats in the intercropped agroforestry sites. including tree trunks,

canopy. leaf litter, crop alleys, herbaœous understory, and plant species (Stamps and

Linit, 1998).

Ground beetles (Carabidae) seemed to be most favourably influenced by the

microenvironmental conditions in the agroforestry sites. Most memben of this family are

generalist predaton, both as adults and as larvae. prefemng humid. undisturôeâ areas

of leaf litter and other organic debris for development (Lang et al.. 1999; Kromp and

Steinberger, 1 992; Dillion and Dillon, 1972). lntercropping agroforestry systems create

long microhabitat conidors, which allow these predators to access the agricultural fieM

where they can forage for prey (Varchola and Dunn. 1999; Petit and Burel, 1998). This

may explain why the carabids were found in greater numbers (9X higher mean) in the

agroforestry field than in the monoculture field. During my field collections, these beetles

were most often observed hiding on the ground under the dark canopy of the Norway

spruce.

Chrysomelidae (leaf beetles) dominated the beetle population in the agroforestry

field (30%). but was not signifïcantly different from the monoculture field. Chrysomelidae

is a species-rich family in terms of the number of species it contains, and most species

are herbivores feeding on a variety of plants and plant parts (Wilcox, 1 979). This family

had a high abundance in the agroforestry sites because of the habitat provided by the

diversity of plant species in the herbaceous understory, as well as the trees themselves.

One important pest species in the family Chrysomelidae attacking corn in

southern Ontario is the northem corn rootworm, Diabrotica bariben Smith and Lawrenœ

(OMAFRA, 1999). This beetle oveminten as an egg in the soil. emerging in the spring

and causing damage ta the corn roots as larvae in midJune to early August; adults

emerge in eariy to midAugust (ESA, 1999). These beetles were found in both the

Page 92: efek tumpangsari thdp keragaman arthropod

80 agroforestry and the monoculture sites. and represented a significant proportion of the

chrysomelids in both fields during August when the aduk were emerging. Almost al1

rootworm eggs are laid in cornfields previousiy planted with corn (OMAFRA. 1999).

Both the monoculture field that was used in 1999. and the crop alleys in the agroforestry

sites during that year had not been planted with corn the year before. Sampling sites in

the agroforestry field, however, were much closer to fields where corn had been planted

in the previous year, than was the monoculture site. Thus, the majority of these beetles

were probably migrants coming into both the agroforestry and monoculture sites. and

the higher numben in the agroforestry field were probably due to its doser proximity to

areas previously planted with corn.

Two orders of omnivorous scavengers were significantly more plentiful in the

agroforestry field than in the monoculhire field: Demptera and Opiliones. The

Opiliones were also found to be more abundant in the tree rows as compared to the

crop alleys in the agroforestry sites.

Only five species of Demaptera Iive in Canada (Danks, 1988). The species most

wmmonly found in Ontario and in my samples, was the European eawig, Fort7cula

auricularia 1. (Vickery and Kevan. 1986). This insed is primarily omnivorous. feeding on

both decaying plant material and small insects (Lamb and Wellington, 1975). It is also

known to feed on living plants when food is scarce (O'Brien. 1 990). Eaiwigs tend to be

noctumal and will seek out shelter in humid areas under leaf litter or in small crevices

during the day. This sheiter protects them from an inhospitable microdimate and

predation. and also provides a location for social interactions to ocair (Lamb and

Wellington, 1975). Feeding activity tends to be uinœntrated in a 50 cm area around the

sheiter. but they will also wander several rneters away within a night (Lamb, 1975).

Female earwigs construct nests in subterranean tunnels or chamben under leaf litter

Page 93: efek tumpangsari thdp keragaman arthropod

areas (Lamb. 1976a). The female remains close her nest, pmtecting her brood from

predators and providing the nymphs with food, until they disperse from the nest and

begin to forage independently (Lamb, 1 976b).

Opiliones are also primarily noctumal and live in humid leaf litter or on tree trunks

(Cloudsley -Thompson, 1958). They are opportunistic scavengers feeding on dead

animal material or soft vegetable matter, and prey on small invertebrates such as

springtails, sowbugs, and mites (Halaj and Cady, 2000; Gertsch, 1979). Female

opiliones generally lay their eggs in the soil. under stones and in other rnoist places

(Cloudsley-Thompson, 1 958).

Populations of both Dermaptera and Opiliones may have been higher in the

agroforestry sites because they provided better microclimatic conditions and sheltering

areas than the open monoculture field. Both of these arthropods require humid

environments to prevent desiccation. decaying animal and plant matenal for food, and

sheltered areas in which to lay their eggs or nest. These arthropods may have been

attracted to the tree rows in the intercropping agroforestry site because of: a) the

undisturbed soiVleaf litter areas for their nests. b) the daytime shelter habitat, and c) the

proximity of the sumnding agricultural foraging area. A recent study examining

Opiliones in a soybean field and hedgerow system (Halaj and Cady, 2000) found a

greater abundance of individuals, and a higher proportion of feeding individuals, in the

hedgerow than in the soybean field. These results wrnplement my findings.

The taxon with the greatest difference between the two treatments was the order

Hymenoptera. This order has memben in several functional groups (predators,

pollinators, parasitoids and herbivores), in addition to being one of the most abundant

orders in my samples. A detailed look at this order suggests that they are a key group

wlh some striking differences between the treatments.

Page 94: efek tumpangsari thdp keragaman arthropod

82 Some researchers consider the family level to provide a good estimate of species

richness and diversity composition (Williams and Gaston. 1993). My work suggests that

there was no differenœ between the agroforestry and the monoculture sites in tems of

overall hymenopteran family richness and diversity. However. dunng the first half of the

season. hymenopteran farnily richness was higher in the agroforestry sites than in the

monoculture field. The only time farnily richness was greater in the monoculture field

was during September. the period when the data may have been affected by the

differenœ in air temperature between the Norway spnice and monoculture sampling

dates. Henœ the anomalous September result may not have been a treatment effect.

The diversity in behaviour and habitat requirements of hymenopterans makes it

difficuit to explain any observed treatment differences at the order ievel. Their functional

roles. however. may be more illuminating in tems of explaining why they were more

abundant in the agroforestry site.

Parasitoids represented the largest group of hymenopteran families (70%)

caught in the intercropped fields. This is not surprising because parasitic

hymenopterans are wnsidered to be the most species-rich functional group within this

order (Lasalle. 1 993). Eig ht parasitic families (31 %) from this functional group were

significantly higher in the agroforestry site than in the monoculture site. and al1 of these

are known to parasitize hosts from a variety of arthropod orders (Table 21). The

behaviour of these families provides some indication as to why they may have had

greater populations in the intercropped sites. For instance, Diapriidae adults generally

prefer damp shady areas (Masner, 1993). which is a microclimatic environment

provîded within the agricultural field in the understory area of the tree rows (Rao et

a/. ,2000).

Page 95: efek tumpangsari thdp keragaman arthropod

Table 21. Eight parasitic hymenopteran families with their preferred hastsa. that were found to have signific~ntly higher mean abundances in the intercropped agroforestry site at the Guelph Agricultural Research Station, during 1999.

Farnily Aduit Host Pupae Host Larvae Host Egg Host Order

Aphelinidae

Chalcididae Diapriidae Encyritidae

Eumilidae Eupelmidae lchneumonidae

Platygastridae

Homoptera Diptera

Lepidoptera Diptera Homoptera Diptera Diptera Homoptera Coleoptera

Diptera Lepidoptera Neuroptera Orthoptera Hemiptera Araneae Hymenoptera Di ptera Coleoptera Coleoptera Diptera Hymenoptera Lepidoptera

Diptera

Lepidoptera Orthoptera

Coleoptera Diptera Lepidoptera Neuroptera Orthoptera Hemiptera Arachnidae Hymenoptera

Araneae

Coleoptera Homoptera

a Goulet and Huber (1 993). Freytag (1 985).

In general, parasitic Hymenoptera are known to be more sensitive to

environmental disturbances than other inseds (Lasalle. 1993). This group as a whole is

known to be affected by rnany factors: a) availability of food for aduits (water, pollen and

nectar), b) availability of altemate hosts. c) availability of habitat (nesting, ovemintering,

refuges, reproduction sites), and d) microclimatic conditions (wind, humidity)

(Tschamtke, 2000; Bugg and Pickett, 1998; Landis and Menalled, 1998). Several

physical characteristics of the intercropping agroforestry field provide many of the

specific requirements of the parasitic hymenopterans, which are not provided by a

conventional monoculture system.

Many aduit parasitoids require fiowering plants for pollen andlor nectar (Attieri,

1994). and flowering vegetation in and around crops has been shown to increase the

parasitism of pest populations (Tschamtke, 2000). Conventional agriculture fields may

Page 96: efek tumpangsari thdp keragaman arthropod

84 have flowering plants, but only in the unculüvated field edges (Thomas and Marshall,

1999). In an intercropping agroforestry system, herbaœous flowering plants are

embedded wWin the agricuitural field in the understory of the tree rows. Queen Anne's

lace (Daucus camta L.), bladder carnpion (Silene vulgans Garcke). and butter cup

(Ranunculus acns L.) were common flowering understory plants in my Celd study area.

The proximity of nectarlpollen to the agricultural crop area where the parasitoids may be

searching for hosts is beneficial for the adult parasitoids (Alieri et al., 1993). In addition

to nectar and pollen sources, arthropods wlhin the tree rows can provide alternative

hosts for the parasitoids during times of host scarcity in the agncuitural crop area

(Stamps and Linit, 1998). Hymenopteran parasitoids are quite habitat specific and

prefer to attack taxonomically unrelated insects found in their favoured habitat, rather

than taxonomically related species within different habitats (Altieri et al., 1993)

Parasitoids often have difficulty in establishing populations in annual crop

monocultures because of detrimental and disniptive agricuitural activities (Wratten and

van Emden, 1995). Tree rows in intercropping agroforestry systems are relatively

undisturbed by mechanical equipment, providing a protected and stable overwintering

area for successive generations of parasitoids.

Finally. some of the hymenopteran parasitoids may have preferred the

intercropping agroforestry site because of reduced windspeed between the tree rows

(Rao et al., 2000). which eases fiight activity. lchneumonids for instance. are large wasp

parasitoids capable of directed flight. They tend to be most active in areas of dense

vegetation, where the windspeed is reduced (Juillet, 1960).

Two predaceous hymenopteran wasp families were significantly higher in the

agroforestry site than in the monoculture site. The first. Pompilidae, are well-known

spider predators, stinging and paralysing their prey to supply food for their offspring in

Page 97: efek tumpangsari thdp keragaman arthropod

underground nests (Brothers and Finnamore, 1993). The other predaceous family,

Sphecidae, establishes nests in the ground. as well as in hollow plant stems or cavities

in wood (Gauld and Bolton. 1988) and are predaceous on a wide vanety of arthropods,

including Orthoptera, Diptera, Hemiptera and Homoptera (Finnamore and Michener,

1993). Both of these families need abundant prey and undisturbed areas for

underground nesting and overwintering as pre-pupae (O'Neit, 2001). This may partially

explain why their populations were greatest in the intercropped agroforestry sites.

Unlike the monoculture field, where the ground is seasonally disrupted by tilling and

harvesting ections, the intercropped fields have large undisturbed areas within the tree

rows. With nesting sites in the tree rows, these families would have easier access to

their prey in the agricultural crop than if they had their nests only along the edges of the

field. With a lower risk of their underground nests k ing destroyed. populations of these

families are better able to build up over the long term.

None of the pollinator families had higher populations in the agroforestry site than

the monocutture site, nor did the pollinator group as a whole differ between the two

treatments. This was surpnsing because it is generally thought that pollinators in an

agmecosystem are depended on undisturbed marginal areas with a diversity of

flowering plants (Svensson et al., 2000; O'Toole. 1993; Lagerlof et al., 1992) and the

weedy understory of the agroforestry tree row would best meet these conditions. It may

be that pollinators were not really attracted to either of these sites despite the number of

weedy flowering species because both the crops and the trees were wind pollinated.

Further research should be conducted to determine whether a change in the crop or

tree species, to ones more dependent on insect pollination (e.g. from the Rosaceae),

would significantly augment the pollinating guild.

Page 98: efek tumpangsari thdp keragaman arthropod

In addition to the number of orders and families with signifmnt population

differenœs between the two fields. two functional trophic groups also had signifimntly

greater population levefs in the intercropped agroforestry field than in the monoculture.

The Crst functional group was the detritivores. The springtails (Collembola) had the

largest abundance within this functionsl group. They are srnall arthropods well known

for their important roles in soi1 respiration and decomposition in agncultural fields

(Lageriof and Andren. 1991). Collembola feed primarily on fungal hyphae and decaying

plant material (Hopkin, 1997) and are thought to improve plant growth through their

feeding on the symbiotic root mycombkae, which in tum stimulates fungal growth

(Lussenhop. 1996). Springtails tend to prefer environments with stable temperatures.

elevated humidity, and high amounts of leaf litterfall of which help stimulate fungal

growth (Hopkin, 1997). Thus it was not surprising that collembolan populations were

sometimes greater in the intercropped sites because of the large amount of leaf Iitter

associateci with the trees and weedy vegetation in the agroforestry sites.

The parasitoids was the second functional group found to be higher in the

agroforestry field than the monoculture field. This group was comprised mainly of

Hymenoptera which, in general, effectively control arthropod populations through their

natural biological control actions, reacting to host population size in a densitydependent

rnanner (Lasalle, 1993). Parasitoids tend to be influenced by food and habitat

availability. as well as microclimatic conditions (Tscharntke, 2000; Bugg and Pickett,

1998; Landis and Menalled; 1998). Thus, my study suggests that the intercropping

agroforestry field was best able to provide the neœssary environmental conditions to

augment parasitoid populations since it could supply pollenlnectar and alternative hosts.

provide the undisturbed ovemintering and nesting areas and provide a more favourable

microclimate (Rao et al., 2000;Starnps and Linit, 1998)

Page 99: efek tumpangsari thdp keragaman arthropod

The ratio between parasitoids and herbivores was higher in the intercropping

agroforestry field than in the monoculture field. These resutts are similar to those of

Peng et al. (1993). who found the ratio of natural enemies (predators and parasitoids) to

pests (specific herbivore pests in their study crop), was generalîy greater in an

agroforestry site than in a monoculhiral control area. My study also found significantly

higher ratios of natural enemies (predators and parasitoids) ta herbivores in the

agroforestry site during the earlier part of the corn growing season (June). This also

corresponds with the Peng et al. (1993) study, which found higher proportions of natural

enemies in the agroforestry site than the monoculture during the first part of the pea

crop-growing season. These parallel findings may have k e n related to the proximity of

overwintering habitat and the availability of prey in the agroforestry location.

Only one order had greater abundance in the monoculture field than in the

agroforestry field, Homoptera. All families in this order are herbivores, some important

pests and known transmitters of viral plant disease (Borror et a/. , 1992).

The majority (65%) of the homopterans caught in the monoculture field were

aphids. Many were the corn leaf aphid, Rhopalosiphum maidis (Fitch), an important pest

of field corn in Ontario (Gualieri and Mcleod, 1994). The corn leaf aphid does not

ovenivinter in Ontario, but instead, is carried into m m fields each year by winds from the

south between mid-July and late September (OMAFRA, 1999; Foott, 1977). Excessive

feeding by this aphid results in stunted corn ean and a risk of infection by the maize

dwarf mosaic virus (Rice, 1996). High numbers of this pest occurred in September in

the agroforestry field and most particulariy in the monoculture field. The increase of this

herbivore in September may have been related to the decline of predators and

parasitoids that occurred during the same time periad.

Page 100: efek tumpangsari thdp keragaman arthropod

88 Ciccadellidae (Leafhoppers) was the only homopteran famiiy to be caught in

significantly larger numbers in the monoculture field than in the agroforestry field. A

large number of leafhopper species feeâ on different kinds of plants including trees.

grasses and shnibs (Borror et al., 1992). Some species; such as the corn leafhopper

(Dalbulus maidis DeLong & Wolcott) are known to attack corn plants (ESA, 1999;

Hruska and Gomez, 1997) and can be vector of diseases such as the maize streak

disease (Rose. 1 972).

The large concentration of homopterans in the monoculture treatment may have

been a result of the pure stands of uniform, young succulent crop plants in this field.

The resource concentration theory (Root. 1973) states that herbivore specialists (like

the corn leaf aphid) are more likely to stay in habitats where their host plants are

concentrated and where their reproductive success is likely to be the greatest. Several

studies that have compared monocultures with polycultures (like the agroforestry field),

have found that monocultures tend to support a larger number of herbiwres than do

polycuitures (Altieri, 1994). Although I found significantly more homopterans in the

monoculture field than in the agroforestry field, there was no difference between the two

treatments in tems of overalf herbivore abundance.

Anthocoridae, minute pirate bugs, was also significantly greater in the

monoculture field than in the agroforestry field. Both nymphs and adults of this

hemipteran family are generalist predators feeding on a variety of small prey, including

spider mites, insect eggs. aphids, thrips, and small caterpillan (Ketton, 1978). One

species in this family that may be important for corn monocultures is the insidious flower

bug (Onus insidous (Say)) a predator of the corn leaf aphid and eggs and larvae of

other lepidopterous corn pests, such as the corn earworm (Heliothis zea (Boddie)) and

the European corn borer (Ostrinia nubilalis (Hubner)) (Reid, 1991). Coll and Bottrell

Page 101: efek tumpangsari thdp keragaman arthropod

89 (1995) also found high numbers of the insidious flower bug within their corn study sites

and relate the high numbers of this generalist predator to food availability (corn pollen

and prey).

Comparison of Norway Spruce and Black Walnut T ree Rows in the lntercropping Agroforestry System

Research in Kenya has shown no e f k d of different tree species on arthropod

abundance in intercropped agroforestry fields (Gima et a/., 2000). In my study however

there was a detectable difference in mean atthropod abundanœ between Nomay

spnice. a wnifer, and Black walnut. a deciduous tree species. in both 1998 and 1999.

These difFerences were reversed between the two yean. with spiders (Araneae) being

higher in pan traps from black walnut dunng 1998 and lower in malaise traps from black

walnut during 1999. It may be that they Iimited data set (one month) in 1998 could

account for these differences and not the trapping method. This suggestion is supported

by the lack of significant differenœs between the two tree species in 1998 for the

predominantly terrestrial orderslclasses like the sowbugs (Isopoda). œntipedes

(Chilopoda) and millipedes (Diplopoda). Further research should examine the two

different sampling methods simultaneously to detemine the cause of this reversal.

Substantial differences in arthropod abundance were obsewed however between

Nomay spruce and black walnut in 1999. Arthropods were more abundant in the spruce

site than the walnut site during the first three months of the season. but not in

September. The notable drop in temperature during September may account for this

lack of signifcanœ in the Norway spnice field, and thus it is not a real treatment effect.

One third of the arthropod orders examined had higher abundance in the Norway

spnice site than in the black walnut site. For the majority of these orden, there was little

difference between population levels in the tree row or in the crop alley. The physical

Page 102: efek tumpangsari thdp keragaman arthropod

90 shape of the two tree species may account for the greater number of arthropods in the

Norway spnice site than in the black walnut site. Conifer trees, such as spruce, are

ainical, allowing sunlight to reach understory plants growing between the trees.

Herbaceous plants under umbrella shaped black walnut trees, however, must grow in a

much shadier environment. Potentially this wann and sunny environment with plentiful

amounts of understory vegetation could be one reason why more arthropods like the

herbivore orthopterans, thysanopterans and hemipterans (the latter two taxa have both

herbivores and predators)(Bonor et al., 1992) were found in higher numbers in spruce

than in black walnut. It is possible that the greater number of spiders (Araneae) in the

Norway spruce site was related to the higher number of arthropod prey found there

(Foelix, 1996). On the other had. the greater number of psocopterans in the spruce tree

rows suggests that the tree rows had a large amount of pollen, mold and algae on which

these insects feed (MocMord, 1993).

Cornparison of T ree Rows and Crop Alleys in the lntercropping Agroforestry System

There was some discrepancy between the results found in 1998 and 1999 in

tenns of tree rows and crop alleys. In the malaise samples. arthropod abundanœ was

the same in the tree row as in the crop alley, corresponding to similar work by Lewis

(1 969a. 1969b). Lewis found that windbreak tree rows can influence the abundance and

diversity of flying arthropod populations in an adjacent crop field up to a distance 10

times the height of the tree row. Since trees in my study were only 4-5 rn tall, the

location of the crop alley was well within the zone of influence, and therefore, it is not

surprising that populations were similar between the rows and alleys.

Of the 15 orders studied in 1999, only Homoptera showed any significant

difference, with higher populations in the crop alleys versus the tree rows. These results

Page 103: efek tumpangsari thdp keragaman arthropod

91 match closely those of G i m et al. (2000). who found significantly greater populations

of aphids (Homoptera) in corn crop alleys than directiy beside tree rows using elevated

water pan traps in Kenya. One explanation for this difference in homopterans could be

the quality of plants growing in the œntre of the crop alley and homopterans' general

feeding preference for young succulent plant growth. Plants in the œntre of the alley

grow in a less stressful environment than those in the tree row where there is

competition for sunlight and moisture. Thus, plants in the middle of the crop alley are

more succulent and may be preferred by homopterans. Lower numbers of natural

enemies would probably not be a factor in this case, because there was no evidence

that the abundanœ of important predaton such as Araneae and Neuroptera. or the

parasitoids in Hymenoptera. differed between the two locations.

In 1998, more arthropods were caught in pan traps in the tree row than in the

crop alley in contrast to 1999. This difFerenœ could be due to the type of arthropods

caught by pan traps (1 998) versus malaise traps (1 999). Ground-dwelling arthropods,

commonly collecteci by pan traps in the soil, may prefer the type of habitat in tree rows

than in crop alleys. It is also possible that these ground arthropods have lower mobility

and are less able to move between the tree rows-and crop alleys than flying arthropods.

making them less inclined to migrate from their preferred habitat. The type of

orders/classes that differed between the two locations supports this suggestion. For

example, œntipedes (Chilopoda), millipedes (Diplopoda) and Daddy long legs

(Opiliones) were al1 higher in the tree rows than in the crop alleys. These groups are al1

active primadly at night, and prefer moist habitats with a rich humus layer during the day

(Borror et al.. 1 992; Cloudsley-Thompson, 1958). Tree rows provide an ideal habitat for

these arthropods, because: 1) the habitat is not disturbed by mechanical plowing

(Stamps and Linit. 1999); 2) the tree canopy maintains relatively high humidity levels

Page 104: efek tumpangsari thdp keragaman arthropod

92 (Rao et al., 2000); and 3) higher leaf litter and understory vegetation (Price, 1999;

Zhang. 1999) provide large amounts of rotting organic material (Vohland and Schroth,

1 999).

Page 105: efek tumpangsari thdp keragaman arthropod

Conclusions My work suggests that intercropping agroforestry influences the composition of

the arthropod community as compared to a monocuîture systern. Although overall

arthropod abundance between these two treatrnents was similar. the abundanœ of

many taxonornic groups was significantly different. This had a subsequent effect on the

functional groupings and the ratio between herbivores and natural enemies.

The effect of these differences among the taxonornic groups was clearly evident

for the order Hymenoptera, where noticeably higher populations resulted in greater

numbers of parasitoids in the intercropping agroforestry site than in the monoculture

site. This variation also led to a higher ratio of parasitaid natural enemies to pest

herbivores in the intercropping agroforestry field, suggesting that it provides a better

habitat for these arthropods. The combined attributes of increased food resources,

improved microclimatic environment, and availability of undisturbed habitat. may all

contribute to enhancing the hyrnenopteran community in the intercropping agroforestry

field. My results correspond in part wlh the natural enemy hypothesis, which predicts a

greater abundance and diversity of natural enemies of pest insectr in vegetationally

diverse environments than in monocultures (Root, 1973). My work also supports reœnt

studies by Stamps et al. (2000) and Peng et al. (1 993). which show higher natural

enemy populations in intercropping agroforestry sites than in monoculture sites. Results

from my study suggest that field crop growers can enhance natural enemy populations

and thereby lower pest populations in their crops by using intercropping agroforestry.

Arthropods dwelling in leaf litter were the second main group affected by the

intercropping agroforestry systern. Many members of this ecological group are active

primarily at night and prefer to shelter in humid leaf litter areas during the day. My

Page 106: efek tumpangsari thdp keragaman arthropod

resuîts showed that these arthropods tended to congregate in the tree rows of the

intercropped site. This may have k e n a resutt of the elevated amounts of vegetative

matter in the tree rows of the agroforestry field. Larger quantities of vegetative maiter

rnay also explain the higher population of detritivores in the agroforestry field as

compared to the rnonocutture field. An increase in detritivores may improve the

breakdown of crop residues left in a field, and thereby improve the health of the soi1 and

the quality of crop production over the long tem. This may be espeàally advantageous

where no-tillage systems are practiced, since this technique leaves substantial

quantities of vegetative matter on the surface of the field.

lntercropping agroforestry systems have k e n shown to improve upon several

environmental problems with conventional agricuitural systems (USDA, 1997). as well

as conserve biodiversity within the agroecosystem (Newman and Gordon, 1997). The

sustainability of Canadian agriculture depends upon a diversity of organisms that play

important roles in maintaining agriculhiral ecological systems (AAFC, 2001). My results

suggest that intercropping agroforestry can provide improved habitat for a diversity of

arthropods in agroecosystems. Therefote measures should be taken to encourage the

adoption of this agricultural system.

Research lmprovemenb and Recommendations

Like many intercropping agroforestry studies in the temperate region (Stamps

and Linit, 1999a). the design of my study has been compromised by a lack of replicated

agroforestry and monoculture fields. This limits the general applicabiiity of my results to

other intercropping agroforestry fields. The fact that my work is similar to that of other

studies (Stamps et al-, 2000 and Peng et a!., 1993) lends support to its broader

Page 107: efek tumpangsari thdp keragaman arthropod

95 implications. A more appropriate design wouid have been to include additional fields, at

a suitable scale and distance from each other (Smith and McSorîey, 2000).

Future studies could produœ a more cornprehensive view of arthropod

communities by simultaneousty employing muttiple trapping methods. One trapping

method that catches primanly ground arthropods (e.g. pan traps or pitfall traps) wuld be

employed in wnjundion with another trapping method that captures primarily aerial

arthropods (e.g. Malaise traps or raised water pan traps). Combining two sampling

techniques may produce a clearer understanding of the ecology both on the ground and

in the air. In my study for instance, using pan traps in conjunction with the Malaise traps

in 1999 cwld have illuminated what was occumng in arthropod groups that are

dependent on leaf litter.

In this study, no significant differenœ was found in the number of pollinators

between the agroforestry and monoculture fields. Other studies shoukl consider

selecting a crop that requires insect pollination, such as clover, squash, strawbemes or

tomatoes. In addition to using an alternative crop in the monoculture and agroforestry

crop alleys, studies should also be conducteci employing tree or shmb species in the

tree rows that require insect pollination, such as rnembers of the genera Prunus or

Amelanchier or tulip-trees (LiMendmn tulipfera L.) .

Arairopod detritivores were found in significantly higher numbers in the

intercropping agroforestry system than in the monoculture system. The higher number

of detritivores could indicate that the use of an agroforestry system would result in

improved breakdown of crop residues. Efforts could be made to compare the activity of

arthropod detritivores in the decomposition of crop residue between intercropping

ag roforestry and monoculture systems.

Page 108: efek tumpangsari thdp keragaman arthropod

96 One veiy important avenue of inquiry that requires further study is to compare

intercropping agroforestry and monoculture systems in ternis of pest damage and crop

yield. To date. this has oniy b e n studied by Ogol et al. (1 999). lntercropping

agroforestry should be promoted as a viable alternative to current agricuitural practices

in the temperate region. This cannot occur without sound data to demonstrate both its

short-terrn and long-terni economic value. Growers will need to be convinced that the

benefits of increased crop yield and monetary retum outweigh the costs of rnuitiple crop

systems and potential pests.

Page 109: efek tumpangsari thdp keragaman arthropod

Literature Sited Agriculture and Agri-food Canada. l997a. Agriculture in Harmony with Nature: strategy for environmentafly sustainable agriculture and agri-food development in Canada. Publication 19371E. Minister of Public Works and Government Services, Ottawa. pp 72.

Ag ricuîture and Agri-food Canada. Environment Bureau. 1997b. Biodiversity in Agriculture: Agriculture and Agri-food Canada's Action Plan. Minister of Public Works and Govemment Services, Ottawa. pp. 45.

Agriculture and Agri-food Canada. 2001 .Agriculture in Harmony with Nature II: Agriculture and Agri-food Canada sustainable development strategy 2001 -2004. Publication 2074E. Minister of Public Works and Govemment Services Canada, Ottawa. pp. 71.

Altieri. M.A. 1991. lncreasing biodiversity to irnprove insect pest management in agro- ecosystems. In: Hawksworth, D.L. (ed.) The Biodiversity of Microorganisms and Invertebrates: Its role in sustainable agriculture. CAB International. Wallingford.UK. pp. 165-1 82.

Altieri, M.A. 1994. Biodiversity and Pest Management in Agroecosystems. Food Products Press. New York. pp. 185.

Altieri, M.A. Cure. J.R. and MA. Garcia. 1993. The role of enhancement of parasitic Hymenoptera biodiversity in agraecosystems. In: Lasalle, J. and 1.0. Gauld (eds.) Hymenoptera and Biodiversity. CAB International, Wallingford , U .K. pp. 257-275.

Andow. D.A. 1991 a. YieM loss to arthropods in vegetationally diverse ecosystems. Environmental Entomology. 20(5): 1228-1 235.

Andow, DA. 1991 b. Vegetational diversity and arthropod population response. Annual Review of Entornology. 36: 561-586.

Andow. D. A. and S.J. Risch. 1985. Predation in diversified agroecosystems: relations between a Coccinellid predator Coleomegila maculata and its food. Journal of Applied Ecobgy. 22: 357-372.

Ausden. M. 1996. Invertebrates. In: Sutherland. W. J. (ed.) Ecolagical Census Techniques: A handbook. Cambridge University Press. Cambridge. pp. 139-177.

Austin. M.T.. Sorenson C.T.. Brewbaker, J.L. Sun W. and H.M. Sheiton. 1995. Forage dry matter yields and psyllid resistance of thirty-one leucaena selections in Hawaii. Ag roforestry Systems. 31 :211-222.

Baldwin, C.S. 1988. The influence of field windbreaks on vegetables and specialty crops. Agriculture, Ewsystems and Environment. 22/23: 1 91 -203.

Page 110: efek tumpangsari thdp keragaman arthropod

98 Banaszak, J. 1992. Strategy for conservation of wiM bees in an agricultural landscape. Ag ricu ttu re. Ecosystems and Environmen t. 4O(ll4): 1 79-1 92.

Barbosa. P. 1 998. Agroecosystems and conservation of biolog ical control. In: Barbosa, P. (ed.) Conservation Biological Control. Academic Press, London. pp. 39-54.

Barbosa, P. and S.D. Wratten. 1998. Influence of plants on invertebrate predators: implications to conservation biolog ical control. In: Barbosa, P. (ed.) Conservation Biological Control. Academic Press, London. pp. 83-1 00.

Beane, K.A. and R.L. Bugg. 1998. Natural and artificial shelter to enhanœ arthropod biological control agents. In: Pickett, C.H. and R.L. Bugg (eds.) Enhancing Biological Control: Habitat management to promote natural enemies of agricultural pests. University of California Press, Los Angles. pp. 239-253.

Biological Survey of Canada.1994. Terrestrial Arthropod Biodiversity: Planning a study and recommended sampling techniques. Supplement to the Bulletin of the Entomokg ical Society of Canada. pp. 1 -33. Website:wuwu. biolog ical.ual berta.calesc. hp/bsdbriefs/brterrestrial. htrn

Bohac, J., and R. Fuchs. 1991. The structure of animal communities as bioindicators of landscape deterioration. In: Jeffrey. D.W. and B. Madden (eûs.) Bioindicators and Environmental Management. Academic Press. London. pp. 165-1 78.

Bond, W.J. 1993. Keystone species. In: Schuke. E.D. and H.A. Mooney (eds.) Biodiversity and Ecosystem Function. Springer-Verlag Berlin Heidelberg, NewYork. pp. 237-253.

Booij. C. J.H. and J. Noorlancier. 1992. Farming systems and insect predators. Agriculture, Ecosystems and Environment. 4O(ll4): 1 25-'l35.

Borror. D. J., Triplehom, C.A. and N.F. Johnson. 1992. An introduction to the study of insects. Sixth edition. Harcourt Brace College Publishers, Orlando. pp.875.

Bowden, J. and G.J.W. Dean. 1977. The distribution of flying insects in and near a tall hedgerow. Journal of Applied Ecology. 14: 343-354.

Brothers, D. J. and A.T. Finnamore.1993. Superfamily Vespoidae. In: Goulet, H. and J.T.Huber (eds.) Hymenoptera of the World: an identification guide to families. Centre for Land and Biological Resources Research, Agriculture Canada, Ottawa. pp. 161-278.

Bruck. D.J. and L.C. Lewis. 1998. Influence of adjacent cornfield habitat, trap bcation. and height on capture numben of predators and a parasitoid of the European Corn Borer (Lepidoptera: Pyralidae) in central Iowa. Environmental Entomology. 27(6): 1557- 1562.

Bugg, R.L. and C.H. Pickett.1998. Introduction: enhancing biological control-habitat management to promote natural enemies of agricultural pests. In: Pickett, C.H. and

Page 111: efek tumpangsari thdp keragaman arthropod

R.LBugg (eds.) Enhancing Biological Control: Habitat management to promote natural enemies of agricultural pests. University of California Press, Los Angles. pp. 1-23.

Bugg , R. L., Anderson, J.H., Thomsen, C.D. and J. Chandler. 1998. Farmscaping in Califomia: managing hedgerows, roadside and wetland plantings, and wild plants for biointensive pest management. In: Pickett, C.H. and R.L. Bugg (eds.) En hancing Biological Control: Habitat management to promote natural enemies of agricuitural pests. iiniverstty of Califomia Press, Los Angles. pp. 339-374.

Burel, F. and J. Baudry. 1995. Farming landscapes and inseds. In: Glen, D.M., Greaves, M.P. and H.M. Anderson (eds.) Ecdogy and integrated farrning systems. John Wley & Sons, Inc., New York. pp.203-220.

Byington, EX. 1990. Agroforestry in the temperate zone. In: MacDicken, K.G. and N.T. Vergara (eds.) Agroforestry: Classification and Management. John Wiley 8 Sons, tnc., New York. pp. 228-289.

Canadian Atmospheric Environmental Services. 1977. Manual of surface weather observations. 7m edition. Central services directorate, Atmospheric Environment, Environment Canada, Ottawa.

Chapman, R.R.1998. The insects: structure and function. 4th ed. Cambridge University Press, Cambridge, U.K. pp. 770.

Cloudsley-Thompson, J.L.1958. Spiders, scorpions, œntipedes and mites: the ecology and natural history of woodlice. 'Myriapods' and Arachnids. Pergarnon Press Ltd., London. pp.228.

Coll. M. 1998. Parasitoid activity and plant species composition in intercropped systems. In: Pickett, C.H. and R.L. Bugg (eds.). Enhancing Biological Control: Habitat management to promote natural enemies of agricultural pests. University of California Press, Los Angles. pp. 85-1 19.

Coll, M. and DG. Bottrell. 1995. Predator-prey association in mono- and dicuîtures: Effect of maize on bean vegetation. Agriculture, Ecosystems and Environment. 541 15- 125.

Corbett, A. 1998. The importance of movement in the response of natural enemies to habitat manipulation. In: Pickett, C. H. and R. L.Bugg (eds.) Enhancing Biological Control: Habitat management to promote natural enemies of agricultural pests. University of California Press, Los Angles. pp. 2547.

Crane, E. 1985. Some muîtipurpose trees that are important honey sources in the tropics and subtropics. In: Proceedings 3" International Conference Apiculture in Tropical Climates, Nairobi, Kenya. International Bee Research Association, London. pp. 192-1 97.

Page 112: efek tumpangsari thdp keragaman arthropod

Danks, H.V. 1988. lnsects of Canada. XVIIIth International Congress of Entomology.Vancouver, British Columbia. Biologicat Survey of Canada (Terrestrial Arthropods). pp. 17.

Darling. D.C. and L.Packer. 1988. Effectiveness of Malaise traps in cullecting hymenoptera: the influence of trap design, mesh size, and location. Canadian Entomologist. 120:789-796.

Day, R.K. and S.T. Murphy.1998. Pest management in tropical agroforestry: prevention rather than cure. Agroforestry Forum. g(2): 1 1-14.

de Bniyn, LA. 1999. Ants as bioindicators of soi1 function in rural environments. Agricuiture, Ecosystems, and Environment. 74(1-3): 425441.

Delaplane, K.S. and D.F. Mayer. 2000. Crop pollination by bees. CAB International Publishing. Wallingforâ, UK. pp. 344.

Dennis, P. and G. Fry. 1992. Field-margins: can they enhanœ natural enemy population densities and general arthropod diversity on familand? Agriculhire, Ecosystems and Environment. 4O(l/4):95-l? 5.

Dillon, E.S. and L.S. Dillon. 1 972. A Manual of Common Beetles of Eastern North America. Dover Publications, New York. pp. 894.

Dix, M.E. 1991. Distribution of arthropod predators of insect pests in and near windbreaks. In: Garrett H. E. (ed.) Proceedings of the Second Conferance on Agroforestiy in North Arnerica. Springfield. Missouri, August 18-22. pp. 295-301.

Dix, M.E. 1996. Pest management in agroforestry systerns: worldwide challenges in the 21st century. Journal of Forestry. 94(9):&11.

Dix, M.E. and D. Leatherman. 1988. lnsed management in windbreaks. Agriculture. Ecosystems and Environment. 22/23: 51 3-537.

Dix, ME, Johnson, R.J., Harrell, M.O., Case, R.M. Wright, R.J., Hodges, L.. Brandle, J.R., Schoeneberger, M.M., Sunderman, N.J., Fitzmaurice, R.L. Younge, L.J. and Hubbard, K.G. 1995. Influences of trees on abundance of natural enemies in insect pests: a review. Agroforestry Systems. 29: 303-31 1.

Dix,M.E., Akkuzu, E., Klopfenstein, N.B., Zhang, J., Kim, M.S. and J.E. Foster.1997a. Riparian refugia in agroforestry systems. Journal of Forestry . 95(8): 3841 .

Dix, M.E., Hodges, L., Brandle. J.R., Wright, R.J. and M.O. Hanell. 1997b. Effeds of shelterbelts on the aerial distribution of insect pests in muskmelon. Journal of Sustainable Agriculture. 9(2/3): 5-24.

Dover, J., Sparks, T. Clarke, S.. Gobbett, K., and S. Glossop. 2000. Linear features and buttemies: the importance of green lanes. Agriculture, Ecosystems and Environment. 80(3): 227-242.

Page 113: efek tumpangsari thdp keragaman arthropod

van Emden, H.F. 1981. Wild plants in the ecology of insed pests. In: J.M.Thresh (ed.) Pests, Pathogens and Vegetation. Pitman Advanced Publishing Program, London. pp. 262.

van Emden, H.F. 1998. Effects of complex mixed cropping systerns on insect pests. Agroforestw Forum. 9(2): 6-8.

van Emden, H.F. and G.F. Williams. 1974. lnsect stability and diversity in agro- ecosystems. Annual Review of Entomology. 19: 455475.

Steffey. K.L., Rice, M.E., All, J., Andow, D.A., Gray, M.E. and J.W. VanDuyn.1999. Handbook of Corn Inseds. Entomological Society of America, Lanham, M.D. pp. 164.

Epila. J.S.O. 1986. The case for insect pest management in agroforestry research. Agricultural Systems. lg(1): 37-54.

Epila, J .S.O. 1 988. Wind, crop pests and agroforestry design. Agricuttural System. 26(2): 99-1 I O .

FAO. 1997. Introduction, screening and evaluation of natural enemies of the leucaena psyllid Hetempsylla cubana for use in biological control programs in Africa. Final report TCPIRAFl4451. pp. 32.

Farrar, J.L. 1995. Trees in Canada. Fitzhenry & Whiteside Limited, Toronto. pp. 502.

Feber, R.E., H. Smith, and D.W. MacDonald. 1996. The effects on butterRy abundance of the management of uncropped edges of arable fields. Journal of Applied Ecology. 33: 1 191 -1 205.

Ferro, D.N. and J.N. McNeil. 1998. Habitat enhanœment and conservation of natural enemies of insects. In: Barbosa. P. (ed.) Conservation Biological Control. Academic Press, London. pp. 123-132.

Finnamore, A.T. 1996. The advantages of using arthropods in ecosystem management. Biological Survey of Canada (Terrestrial Arthropods) Briefs. Website: http:/lwww. biology. ualberta.ca/esc. hp/bsc/briefs/bradvantages. htm

Finnamore, A.T. and C. D. Michener. 1993. Superfamily Apoidae. In: Goulet, H. and J.T.Huber (eds.) Hymenoptera of the World: an identification guide to families. Centre for Land and Biological Resources Research, Agriculture Canada, Ottawa. pp. 279-357.

Foelix, R. F.1996. Biology of Spiders. Harvard University Press, Cambridge, Mass. pp. 306.

Follett, P. and G. Roderick. 1996.Genetic estimates of dispersal ability in the leucaena psyllid predator Cunnus coemleus (Coleoptera: Coccinellidae): implications for biological control. Bulletin of Entomological Research. 86: 355-361.

Page 114: efek tumpangsari thdp keragaman arthropod

Foott, W. H. 1977. Biology of the Comleaf Aphid, Rhopalosiphum maidis (Homoptera: Aphididae), in Southwestern Ontario. Canadian Entomologist. 109(8): 1 129-1 1 35.

Freytag, P.H. 1985. The insect parasites of leafhoppers, and related groups. In: Nault.L.R., Rodriguez, J.G. and DeLong, D.M. (ed.) The Leafhoppen and planthoppers. John Wiley and Sons, Inc., New York. pp. 423427.

Fry, G. 1995. Landscape ecology of insect movement in arable ecosystems. In: D.M. Glen, M.P. Greaves, and H.M. Anderson (eds.) Ecology and integrated faming systems. John Wley and Sons Ltd. pp. 356.

Gange, A.C. and M. Llewellyn. 1989. Factors affecting orchard colonkation by the black-kneed capsid (Blepharidoptems angulatus (Hemiptera : Mi ri rdae)) from alder windbreaks. Annals of Applied Biology. 1 14(2):22l-230.

Garrett, HE., Jones, J.E., Kurtz, W.B, and J.P. Slusher. 1991. Black walnut (Juglans nigm L.) agroforestry-its design and potential as a land-use alternative. The Forestry Chronicle. 67(3):213-218.

Gauld, 1. and B. Bolton. 1988. The Hymenoptera. Oxford University Press, Oxford, U.K. pp. 332.

Gertsch, W. J. 1979. Amencan Spiders. van Nostrand Reinhold Ltd., New York. pp. 274.

Girma, H., M.R.Rao, and S. Sithanatham. 2000. lnsect pests and beneficial arthropod populations under different hedgerow intercropping systems in semiarid Kenya. Agroforestry Systems. 50(3): 279-292.

Gliessman, S.R. I W O . Agroecology: researching the ecological basis for sustainable agriculture. In: Gliessman, S. (ed.) Agroecology: researching the ecological basis for sustainable agriculture. Springer-Verlag New York Inc.

Gordon. A.M. and P.A. Williams. 1991. lntercropping valuable hardwood tree species and agncultural crops in Southem Ontario. The Forestry Chronicle. 67(3): 200-208.

Gordon. A.M., Newman, S.M. and P.A. Williams. 1997. Temperate Agroforestry: an overview. In: Gordon. A. M. and S.M. Newman (eds.) Temperate Agroforestry Systems. CAB International. Wallingford, UK. pp. 18.

Goulet, Henri and John T Huber. 1993. Hymenoptera of the Worid: an identification guide to families. Publication 1894lE. Research Branch, Agriculture Canada. Canada Communication Group Publishing, Ottawa. pp. 668.

Gualeri. L.L. and D.G.R. McLeod. 1 994. Atlas of aphids trapped in agncultural crops. Research Branch, Agriculture and Agri-Food Canada. London, Ontario. Publication 1901IE. pp. 63.

Page 115: efek tumpangsari thdp keragaman arthropod

7 O 3 Green, S. B. 1906. Farm wind-breaks and shelter-beits : their formation and care. Webb Publishing Company, St. Paul., Minnesota. pp. 69.

Gurr, G.M., van Emden, H.F. and S.D.Wratten.1998.Habitat manipulation and natural enemy efficiency: implications for the control of pests. In: Barbosa, P. (ed.) Conservation Biological Control. Academic Press, London. pp. 1 551 84.

Halaj, J. and A.B. Cady. 2000. Diet composition and signifimnœ of earthwoms as food of harvestmen (Arachnida: Opiliones). The Arnerican Mid land Naturalist. 143(2): 487- 491.

Hassall, M., A. Hawthorne, M. Maudsley, P. White, and C. Cardwell. 1992. Effects of headland management on invertebrate communities in œreal fields. Agriculture, Ecosystems, and Environment. 40(1/4):155-178.

Helenius. J.1998. Enhancement of predation through within-file divenitfication. In: Pickett, C.H. and R.L.Bugg (eds.) Enhancing Biological Control: Habitat management to promote natural enemies of agricultural pests. University of California Press, Los Angles. pp. 121 -1 59.

Hill, D.S. 1997. The Economic Importance of Insects. Chapman and Hall, London. pp. 395.

Hodge, S., Garrett, HE. and J. Bratton. 1999. Alley Cropping: An agroforestry practice. Agroforestry Notes #12. The National Agroforestry Centre. USDA Forest Service and USDA Natural Resources Conservation Servi-. Lincoln, Nebraska. pp.6.

Hoekstra, D. A. 1990. Economics of agroforestry. In: MacDicken, K.G. and N.T. Vergara (eds.) Agroforestry: Classification and Management. John Wley & Sons, Inc., New York. pp. 310-331.

Holland, J. and L. Çahrig. 2000. Effect of woody borders on insect density and diversw in crop fields: a landscape-scale analysis. Agriculture, Ecosystems, and Environment. 78(2): 1 1 5-1 22.

Holldobler, B. and E.O. Wilson. 1990. The ants. Harvard University Press, Cambridge, Mass. pp.732.

Holloway, J.D. and N.E. Stork. 1991. The dimensions of biodiversity: the use of invertebrates as indicators of human impact. In: Hawksworth, D.L. (ed.) The Biodiversity of Microorganisms and Invertebrates: Its Role In Sustainable Agriculture. CAB International, Wallingford, UK. pp. 302.

Holt, R.D., Dbinski, D.M., Diffendorfer, J.E., Gaines, M.S., Martinko, E.A., Robinson, GR., and G.C. Ward. 1995. Perspectives from an experimental study of habitat fragmentation in an agroecosystem. In: Glen, D.M., Greaves, M.P. and H.M. Anderson (eds.) Ecology and lntegrated Farming Systems. John Wiley and Sons Ltd., New York. pp.147-174.

Page 116: efek tumpangsari thdp keragaman arthropod

Hopkin. S. 1997. Biology of the Springtails (Insecta: Collembola). Oxford University Press. Oxford, UK. pp. 330.

Howes, F.N. 1979. Plants and Beekeeping: an account of those plants, wild and cuttivated, of value to the hive bee for honey production in the British Isles. Faber and Faber, London. pp. 236.

Hniska, A.J. and P.M. Gomez. 1997. Maize -response to corn leafhopper (Homoptera: Cicadellidae): infestation and achaparramiento disease. Joumal of Economic Entomology. 90: 604-6 1 0.

Huxley, P.A. 1983. Some charaderistics of trees to be consideted in agroforestry. In: Huxley, PA. (ed.) Plant research and agroforestry, ICRAF Publication.pp.3-12. C M in: Epila, J.S.O. 1986. The case for insect p s t management in agroforestry research. Agricuitural Systems. 1 S(1): 37-54.

Huxley, PA. and D.J. Greenland. 1989. Pest management in agroforestry systems: A record of discussions held at CAB International, Wallingford, UK. 28-29 July 1988. Agroforestv Abstracts 2(2): 3 7 4 . Cited in: Rao, M.R., Singh, M.P. and R. Day. 2000. lnsect problems in tropical agroforestry systems: contributory factors and strategies for management. Agroforestry systems. 50(3): 243-277.

1perti.G. 1999. Biodiversity of predaceous Coccinellidae in relation to bioindication and economic importance. Agriculture, Ecosystems and Environment 74(1-3):323-342.

Jackson, J.P. 1987. Soybeans & Sawlogs: the promise of agroforestry. American Forests. 93: 26-31.

Jensen, P. B. 1997. The influence of unspraying on diverstty of soil-related Hymenopteran parasitoids in œreal fields. Joumal of Applied Entomology. 121 :417424.

Juillet, J.A. 1960. S o m factors influencing the flight activity of hymenopterous parasites. Canadian Journal of Zoology. 38: 1057-1 061.

Juillet, J.A. 1964. Influence of weather on flight activity of parasitic Hymenoptera. Canadian Joumal of Zoology. 42: 1 133-1 141.

Kareiva, P. 1983. The influence of vegetation texture on herbivore populations: resource concentration and herbivore rnovement. In: Denno, R.F. and M.S. McClure (eds.) Variable Plants and Herbivores in Natural and Managed Systems. Academic Press, New York. pp. 259-289.

Kelton, L. A. 1978. The Anthocoridae of Canada and Alaska (Heteroptera: Anthocoridae). lnsects and Arachnids of Canada, Part 4. Bisosystematics Research Institute, Agriculture Canada. Canadian Govemment Publishing Centre, Ottawa. pp. 1 01.

Page 117: efek tumpangsari thdp keragaman arthropod

Kotey, E.1997. Effects of tree and crop residue mulches and herbicides on weed populations in a temperate agroforestry system (glyphosate. imazethapyr). MSc thesis. University of Guelph, Guelph, Ontario, Canada. pp. 150.

Krebs, C. J. 1 994. Ecology: The experimental anaiysis of distribution and abundance. Harper Collins College Publishers. New York. pp. 801.

Krebs, C. J. 1999. Ecological method0logy.2~ edition BenjaminlCummings, Menlo Park, California. pp. 620.

Kromp, 8.1999. Carabid beetles in sustainable agriculture: a review on p s t control efficacy, culavation irnpads and enhancement. Agriculture, Ecosystems and Environment. 74(1-3): 1 87-228.

Kromp, B and K.H. Steinberger.1992. Grassy field margins and arthropoâ diversity: a case study on ground beetles and spiders in eastem Austria (Coleoptera: Carabidae; Arachnida: Aranei. Opiliones ). Agriculture, Ecosystems and Environment. 40(114): 71- 93.

Krooss, S. and M. Schaefer. 1998. The effect of different faming systems on epigeic arthropods: a Cve-year study on the rove beetle fauna (Coleoptera: Staphylinidae) of winter wheat. Agriculture, Ecosystems. and Environment. 69(2): 121 -1 33.

Kurtt,W.B., Thurman, S.E., Monson,M.J. and H.E. Garrett. 1991. The use of agroforestry to control erosion - financial aspect. The Forestry Chronick 67(3): 254- 257.

Lagerlof, J. and 0. Andren. 1991. Abundanœ and activity of Collembola. Protura and Diplura (Insecta, Apterygota) in four cropping systems. Pedobiologia. 35(6): 337-350.

Lagerlof, J., Stark, J. and B. Svensson. 1992. Margins of agricultural fields as habitats for potlinating insects. Agriculture, Ecosystems and Environment. 4O(ll4): 1 17-1 24.

Lamb. R.J. 1975. Effects of dispersion, travel, and environmental heterogeneity on populations of the earwig Forficula auricularia 1. Canadian Journal of Zoology. 53: 1855-1 867.

Lamb, R. J. 1976. Dispersal by nesting earwigs, Foficula auricularia (Dermaptera: Forficulidae). The Canadian Entomologist. 1 OB: 21 3-21 6.

Lamb, R.J. 1976. Parental behavior in the Dermaptera with special referenœ to Foficula auricularia (Dermaptera: Forficulidae). The Canadian Entomologist. 108: 609- 619.

Lamb, R. J. and W.G. Wellington. 1975. Life history and population characteristics of the European earwig, Fodicula auticutaria (Dennaptera: Foficulidae). at Vancouver, British Columbia. The Canadian Entomologist. 107: 81 9-824.

Page 118: efek tumpangsari thdp keragaman arthropod

Landis, D.A. 1 994. Arth ropod sampling in ag ricuttu ral landscapes: ecolog id considerations. In: Pedigo, L.P. and G.D. Buntin (eds.) Handbook of Sampling Methods for Arairopods in Agriculture. CRC Press. Inc.. Florida. pp.1531.

Landis. D.A. and F.D. Menalled. 1998. Ecological considerations in the conservation of effective parasitoid communities in agricultural systems. In: Barbosa, P. (ed.). Consenration Biological Control. Acadernic Press, London. pp 101-120.

Landis, D.A., Wratten, S.D. and G.M. Gurr. 2000. Habitat management to conserve natural enemies of arthropod pests in agriculture. Annual Review of Entomology . 45: 175-201.

Lang, A., Filsner. J.. and J.R. Henschel. 1999. Predation by ground beetles and wolf spiders on herbivorous insects in maire crop. Agriculture, Ecosystems, and Environment. 72(2): 189-1 99.

Lasalle, J. 1993. Parasitic Hymenoptera, biological control and biodiversity. In: Lasalle, J. and I.D. Gauld (eds.) Hymenoptera and Biodivencty. CAB International. Wallingford. O.K. pp. 197-215.

LaSa1le.J. 7999. lnsed biodiversity in agroecosystems: fundion. value and optirniration. In: Wood. D. and J.M. Lenne (eds.) Agrobiodiversity: Characteriration, Utilization and Management. CAB International Publishing, Wallingford, UK. pp. 155-1 82.

Lasalle. J. and lan D. Gauld. 1993. Hymenoptera: their diversity, and their impact on the diversw of other organisms. In: Lasalle, J. and 1. D. Gauld (eds.) Hymenoptera and Biodiversity. CAB International. Wallingford, U.K. pp. 1-26.

Lawrence, J.F. 1 991 . Order Coleoptera. In: Çtehr. F.W.(ed .) Immature insects. vol. 2. KendalVHunt Publishing Co., Dubuque. Iowa. pp.768.

Letoumeau, D. 1997. Plant-Arthropod Interactions in agroecosystems. In: Jackson, L. (ed.) Ecology in Agriculture. Academic Press San Diego. California. pp. 239-290.

Letoumeau. D. 1998. Conservation biology: lessons for conserving natural enemies. In: Barbosa. P. (ed.) Conservation Biological Control. Academic Press. London. pp. 9-37.

Leuty. T. 1999. lntercropping trees and annual crops. Ontario Ministry of Agriculture, Food and Rural AffairsGuelph. Website:www.gov.on.ca/OMAFRA/english/cropslfa~d info-intercrop. htm

Lewis. T. 1965. The effects of shelter on the distribution of insect pests. Scientific Horticulture. 17: 74-84.

Lewis. T. 1969a. The diversity of the insect fauna in a hedgerow and neighboring field. 6: 453458.

Lewis, T. 1969b. The distribution of flying insects near a low hedgerow. Journal of Applied Ecology. 6: 443452.

Page 119: efek tumpangsari thdp keragaman arthropod

Lewis, T., 1970. Patterns of distribution of insects near a windbreak of tall trees. Annals of Applied Biology. 65(2): 213-220.

Lewis, T. and B.D. Smith. 1972. The effects of windbreaks on the blossom-visiting fauna of apple orchards and on yield. Annals of Applied Biology. 72: 229-238.

Luff, M.L. 1983. The potential of predators for pest control. Agriculhire, Ecosystems and Environment. 27: 241 -251.

LussenhopJ. 1996. Collembola as mediators of rnicrobial symbiont effect to soybeans. Soil biology and biochemistry. 25: 775-80. Cited in: Hopkin, S. 1997.Biology of the Springtails (Insecta: Collernbola) . Oxford University Press, Oxford, UK. pp . 330.

Lys, J.A. and W. Nentwig. 1992. Augmentation of beneficial arthropods by strip- management. Surface activity, movements and activity density of abundant carabid beetks in a cerea l field. Oecologia. 92(3): 373-382.

Lys, J.A. and W. Nentwig. 1994. lmprovement of the overuvintering sites for Carabidae, Staphylinidae and Aranea by strip-management in a cereal field. Pedobiologia. 38:238- 242.

MacDicken, K.O. and N.T. Vergara. 1990. Introduction to Agroforestry. In: MacDicken, K.G. and N.T. Vergara (4s.) Agroforestv: Classification and Management. John Wiley & Sons, Inc., New Yotù. pp. 1-28.

Magurran, A. E.1988. Ecological diverstty and its measurement. Princeton University Press, Princeton, N.J. pp. 179.

Macleod, A. 1999. Attraction and retention of Episyrphus bateatus DeGeer (Diptera: Syrphidae) at an arable field margin with rich and poor floral resources. Agriculture. Ecosysterns, and Environment. 73(3): 237-244.

Mallory, E. 1993. Effects of some rehabilitative measures on reaches of two degraded streams draining agricultural areas. MSc thesis, Universtty of Guelph, Guelph, Ontario, Canada. pp 154.

Marshall. E. and B. Smith. 1987. Field margin flora and fauna: interaction with agriculture. In: Way, J.M. and P.W. Greig-Smith (eds.) Field Margins. British Crop Protection Council Monograph No. 35. B.C.P.C. Publications, Famham, U.K. pp. 23-33.

Marshall, V. G., Kevan, D. K., Matthews, J. V. and A. O. Tomlin.1982. Status and research needs of Canadian soi1 arthropods. The Bulletin of the Entomological Society of Canada. 14 (l).Biological Survey of Canada (Terrestrial Arthropods). Website: http://www. biology. ualberta.calesc. hp/bsC/briefslbrstatus. h t l

Martin, J.E.H. 1977.The lnsects and Arachnids of Canada Part 1 : Collecting, Preparing and Preserving Insects, Mites and Spiders. Biosystematics Research Institute. Research Branch of Canada Department of Agriculture, Ottawa. pp.147.

Page 120: efek tumpangsari thdp keragaman arthropod

Masner, L. 1993. Superfamily Prototrupoidae. In: Goulet, H. and J.T Huber (eds.) Hymenoptera of the World: an identification guide to families. Publication 1894lE. Research Branch, Agriculture Canada. Canada Communication Group Publishing, Ottawa. pp.537-557.

Masner. L., Barron, J.R., Danks, H.V., Finnamore, AT., Francoeur, A., Gibson, G.A.P., Manson, W.R.M., and C.M. Yoshimoto. 1979. Hymenoptera. In: Danks, H.V. (ed.) Canada and its lnsect Fauna. Memoirs of the Entomological Society of Canada ; Number no. 1 08. Entomological Society of Canada. Ottawa. pp. 485508.

Mason, W.R.M and J.T. Huber. 1993. Oder Hymenoptera. In: Goulet, H. and J.T Huber (eds.) Hymenoptera of the Worîd: an identification guide to families. Publication l894/E. Research Branch, Agriculture Canada. Canada Communication Group Publishing, Ottawa. pp. 4-12.

Matteson, P.C., Altieri, M.A. and W.C. Gagne. 1984. Modification of small famer practices for better p s t management. Annual Review of Entomology. 29: 383-402.

Matthews, S., Pease, S.M., Gordon,A.M. and P.A.\Nilliams. 1993. Landowner perceptions and the adoption of agroforestry pradces in southem Ontario, Canada. Agroforestty Systems. 2 1 : 159-1 68.

Maudsley, M. J. 2000. A review of the ecology and conservation of hedgerow invertebrates in Britain. Journal of Environmental Management. 60(1): 65-76.

McAlpine, J.F. 1981 . Key to families-adults. In: McAlpine, J.F., Peterson,B.V. and G.E. Shewell (eds.) Manual of Nearactic Diptera. Volume 1. Canadian Department of Agriculture Monograph 27. Research Branch Agriculture Canada, Biosystematics Research Instlute, Ottawa. pp. 674.

Mchowa, J.W. and D.N. Ngugi. 1994. Pest amplex in agroforestry systems: the Malawi experienœ. Forest Ecology and Management. 64: 277-284.

Metcalf, R.L. 1999. Arthropods as pests of plants: an overview. In: Ruberson, J.R. (ed.) Handbook of Pest Management. Marcel Dekker, Inc., New York. pp. 377-394.

Mitchell, L.G., Mutchmor, J.A. and W.D. Dolphin. 1988. Zoology. The BenjaminICummings Publishing Company, Inc., California. pp. 862.

Mockford, E.L. 1993. North America Psocoptera (Insecta). Sandhill Crane Press, Gainesville, Florida. pp. 455.

MOSS~ D.N. 1964. Some aspects of microclimatology important in forage plant physiology. In: Forage plant physiology and soil-range relationship. Amencan Society of Agronomy Special Publication No. 5. American Society of Agronomy, Wisconsin, USA, pp. 1-14. Cited in: Williams, P.A., Gordon, A.M., Garrett, H.E., and L. Buck. 1997. Agroforestty in North Amerka and its role in farming systems. In: Gordon, Andrew M.

Page 121: efek tumpangsari thdp keragaman arthropod

and Steven M. Newman (eds.) Temperate Agroforestry Systerns. CAB International, Wallingford, UK. pp. 984.

Murphy. B.C., Rosenheim, J.A.. Granett, J., Pickett, C.H. and R.V. Dowe11.1998. Measuring the impact of a natura! enemy refuge: the prune tree 1 vineyard example. In: Pickett. Charles H. and Robert 1. Bugg (eds.) Enhancing Biological Control: Habitat management to promote natural enemies of agncultural pests. University of Califomia Press, Los Angles. pp. 297-309.

Murrary, J. L. 1997. Agricuttural change and environmental consequence in southem Ontario, 1951 -1 971. MSc. thesis. Univerisity of Guelph. Guelph, Ontairo, Canada.pp.120.

Nair, P.K.R. 1990. Classification of agroforestry systems. In: MacDicken, K.G. and N.T. Vergara (eds.) Agroforestry: Classification and Management. John Wley 8 Sons, Inc., New York. pp. 382.

Nair, P.K.R. 1993. An Introduction to Agroforestry. Kluwer Academic Publishers in woperation with the International Centre for Research in Agroforestry. pp. 499.

Nair. P.K.R. 1996. Agroforestry directions and literature trends. In: McDonald, P. (ed.) The Literature of Forestry and Agroforestry. Comell University Press. Ithaca, New York. pp. 74-95.

National Association of Resource Conservation and Development Councils. Inc. 2000. RC&D survey of agroforestry practices. Washington D.C. pp. 29. Website: www.rcdnet.org/agro. htrn

Neff, J. L. and B. B. Simpson.1993. Bees, pollination systems and plant diversity. In: Lasalle. J. and I.D. Gauld (eds.) Hymenoptera and Biodiversity. CAB International. Wallingford, U. K. pp. 143-1 67.

Nelson, €.A. and M.J. Linit. 1999. A cornparison of the effects of black walnut-forage alley cropping system on numbers of carabids. In: The poster abstracts of the sixth conference on agroforestry in Nom America. June 12-16, 1999. Hot Springs. Arkansas. pp. 37.

Nentwig, W. 1998. Weedy plant species and their beneficial arthropods: potential for manipulation in field crops. In: Pickett,C.H. and R.L.Bugg (eds.) Enhancing Biological Control: habitat management to promote natural enemies of agricultural pests. University of Califomia Press, Los Angeles. pp. 49- 84.

Nentwig, W., Frank, T. and C. Lethmayer. 1998. Som weed strips: artificial ecological compensation areas as an important tool in conservation biological control. In: Barbosa, P. (ed.) Conservation Biological Control. Academic Press, London. pp. 1 33-1 56.

Newman, S. M. and A.M. Gordon. 1 997. Temperate agroforestry: synthesis and future directions. In: Gordon, A. M. and S.M. Newman (eds.) Temperate Agroforestry Systems. CAB International, Wallingford, UK. pp. 251-266.

Page 122: efek tumpangsari thdp keragaman arthropod

Noms, R.F. and M. Kogan. 2000. Interactions between weeds, arthropod pests. and their natural enemies in rnanaged ecosystems. Weed Science. 48:94-158.

O'Brien, M.F. 1990. Earwigs in Michigan. Entomological Notes No. 21. Michigan Entomological Society. Michigan State Universrty, East Landing, Michigan. pp 2.

Ogol, C.K.P.O. and J.R. Spenœ. 1997. Abundance, population dynamics and impact of the leucaena psyllid Hetemsphylla cubana Crowford in a maize-leucaena agroforestry system in Kenya. lnsect Science Application. 17: 183- 192.

Ogol, C.K.P.O.. Spence. J.R. and A. Keddie.1998. Natural enemy abundanœ and activity in a maire-leucaena agroforestry system in Kenya. Environmental Entomology. 27: 1444-1451.

Ogol, C.K.P.O., Spence. J.R. and A. Keddie. 1999. Maize stem borer colonization, establishment and crop damage b e l s in a maize-leucaena agroforestry system in Kenya. Agriculture, Ecosystems, and Environment. 76(1): 1-1 5.

O'Neil, K. 2001. Solitary Wasps: behaviour and natural history. Comell University Press, Ithaca, New York. pp. 406.

Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). 1999. Field Crop Recommendations. Publication No. 296. Queens Printer for Ontario. pp. 136.

O'Toole, C. 1993. Diversity of native bees and agroecosystems. In: Lasalle, J. and I .D. Gauld (eds.) Hymenoptera and Biodiversity. CAB International. Wallingford, U.K. pp. 169-1 96.

Paoletti, M.G. 1 999. Using bioindicators based on biodiversity to assess landscape sustainability. Agriculture, Ecosystems, and Environment. 74(1-3): 1-1 8.

Paoletti. MG., Pimentel, D., Stinner. B. R. and D.Stinner. 1 992. Agroecosystem biodiversity: matching production and conservation biology. Agriculture, Ecosystems and Environment. 403-23.

Paoletti, M. and M. Hassall. 1999. Woodfice (lsopoda: Oniscidea): their potential for assessing sustainability and use as bioindicaton. Agricutture, Ecosystems, and Environment. 74(1-3): 157-1 65.

Pasek. J.E. 1988. Influence of wind and windbreaks on local dispersal of insects. Agriculture, Ecosystems, and Environment. 22/23: 539-554.

Peng, R.K.. L.D. Incoll, S.L. Sutton, C. Wright, and A. Chadwick. 1993. Diversity of airbome arthropods in a silvoarable agroforestry system. Journal of Applied Ecology. 30: 551 -562.

Page 123: efek tumpangsari thdp keragaman arthropod

Petit, S. and F. Burel. 1998. Effects of landscape dynamics on aie metapopulation of a ground beetle (Coleoptera. Carabidae) in a hedgerow neîwork. Agriculture, Ecosystems, and Environment. 69(3): 243-252.

Pimentel, D. 1 995. Ecological theory, pest problems, and biologically based solutions. In: Glen, D.M. Greaves, M.P. and H.M. Anderson (eds.) Ewlogy of lntergtated Farming Systems. John Wiley and Sons Ltd., New York. pp. 69-82.

Pimentel, O., Stachow, U. ,Takacs, D.A., Brubaker, H.W., Dumas, A.R., Meaney, J. J., O'Neil. J.A.S., Onsi,D.E. and D.B. Conilius. 1992. Consenring biological diversrty in agriculturallforestry systems. Bioscience. 42(5): 354-362 .

Price, G.W.1999.Spatial and temporal distribution of earthworms (Lumbricidae) in a temperate intercropping system in southem Ontario (Lumbncidae). MSc thesis. University of Guelph, Guelph, Ontario. Canada. pp.131.

Price, G.W. and A.M. Gordon. 1999. Spatial and temporal distribution of earthwons in a temperate intercropping system in southem Ontario Canada. Agroforestry Systems. 44(2/3): 141-149.

PrÏce, P.W. 1997. lnsect Ewlogy. John Wiley and Sons, Inc., New York. pp.874.

Rachie, K.0.1983. lntercropping tree legumes with annual crops. In: Huxley, PA. (ed.) Plant research and agroforestry. ICRAF Publication. pp 271-289. Cited in: Epila, J.S.O. 1 986. The case for insect pest management in agroforestry research. Ag ricultural Systems. 1 Q(1): 37-54.

Raintree, J.B. 1990. Theory and practice of agroforestry diagnosis and design. In: MacDicken, K G . and N.T. Vergara (eds.) Agroforestw: Classification and Management. John Wley 8 Sons, Inc.. New York. pp. 58-97.

Rao, M.R., Singh, M.P. and R. Day. 2000. lnsect problems in tropical agroforestry systems: contributory factors and strategies for management. Agroforestry systems. 50(3): 243-277.

Reid. Craig, D. 1991. Ability of 0th insidiosus (Hemiptera: Anthocoridae) to search for, find, and attack European corn borer and corn earworm eggs on corn. Journal of Economic Entomology. 8483-86.

Reinhard, H.J. 1943. Hibernation of the bol1 weevil. Bulletin of the Texas Agricultural Experirnent Station, no. 638. College Station, Texas. pp. 23.

Rice, M.E.1996. lnsect Pests of Corn. lntegrated Pest Management publication, no. 31. University Extension Services, lowa State University, Ames, lowa. pp. 8.

Risch, S.J. 1981. lnsect herbivore abundance in tropical monocultures and polycultures: an experiment test of two hypotheses. Ecology. 62: 1 325-1 340.

Page 124: efek tumpangsari thdp keragaman arthropod

Risch, S.J., Andow. D. and M.A. Altieri. 1983. Agroecosystem diversity and pest control: data, tentative conclusions and new research directions. Environmental Entomology. 12(3): 625-629.

Root, R.B. 1973. Organization of plant arthropod associations in simple and diverse habitats: the fauna of collards (Brassice oleracea). Ecological Monographs. 43:95424.

Rose, D.J.W. 1972. Times and sires of dispersal flights by Cicadulina species (Homoptera: Cicadellidae), vectors of maire streak disease. Journal of Animal Ecology. 41 : 495-506.

Rule. L., Colleto. J., Liu. T., Jungst, S., Mize, C. and R. Schultz. 1993. Agroforestry in the Midwestem United States. In: Colletti, J.P. and R.C. Schultz (eds.) Opportunities for Agroforestry in the Temperate Zone Worîdwide. Proceedings of the Third North Arnerican Agroforestry Conference. August 15-18, 1993, Ames, IA.

Russell, €.P. 1989. Enemies hypothesis: a review of the effect of vegetational divenity on predatory insects and parasitoids. Environmental Entomology. 18: 590-599.

SAS Institue lnc. 1996. SAS 6.1 2. Cany, North Carolina.

Schowaîter, T.D. 2000. Insect Ecology: an ecosystem approach. Academic Press, London. pp. 483.

Schroth, G.. Krauss, U., Gasparotto, L., Duarte Aguilar, J.A. and K.Vohland. 2000. Pests and diseases in agroforestry systems of the humid tropics. Agroforestry Systems. 50(3): 199-241.

Shelton, H.M. and J.L. Brewbaker 1994. Leucaena leucocephala - the Most W~dely Used Forage Tree Legume. In: Gutteridge, R.C. and H. M. Shelton (4s.) Forage tree legumes in tropical agriculture. CAB International. Wallingford, UK. pp.178.

Sharkey, M.J. 1996. Malaisemight intercept sampling protocds. In: Finnamore, A.T. (4.) The SAGE project: a workshop report on terrestrial arthropod sampling protocols for graminoid ecosystems. Provincial Museum of Alberta, Website: www.cciw.ca/eman- temp/reports/publications/sage/sagel . htm

Sheehan, W. 1986. Response by specialist and generalist natural enemies to agroecosystem diversification: a seleme review. Environmental Entomology. 15:456- 461.

Sileshi,G..Maghembe, J.A., Rao,M.R., 0gol.C.K.P.O and S.Sithanantham. 2000. lnseds feeding on Sesbania species in natural stands and agroforestry systems in southem Malawi. Agoforestry Systems. 49(1): 41-52.

Simpson, J.A.1999. Effects of shade on maize and soybean productivity in a tree-based intercrop system (Populus deltoides x nigra, Acer saccharum) MSc thesis. University of Guelph, Guelph, Ontario, Canada. pp. 106.

Page 125: efek tumpangsari thdp keragaman arthropod

113 Singh, M.P. and Panhar, D.R. 1997. lnsect p s t management in silvipastoral system. In: Yadav. M.S., Manjity, S., Shama. S.K. and U. Burman (eds.) Silvipastoral systems in arid and semi-and ecosystems. UNESCOICAZRI. Johhpur, India. pp. 371-385. Cited in: Rao, M.R., Singh, M.P. and R. Day. 2000. lnsect problems in tropical agroforestry systems: contributory factors and strategies for management. Agroforestry Systems. SO(3): 243-277.

Slosser. J.E., Fewin, R.J., Price, J.R. and J.R. Bryson. 1984. Potential of shelterbeit management for bol1 weevil (Coleoptera:Curculionidae) control in the Texas rolling plains. Journal of Economic Entomology. 77: 377-385.

Smith, H.A. and R. McSorley. 2000. lntercropping and pest management: a review of major concepts. Arnerican Entomologist. 46(3): 154-161.

Snell, T.K. 1998. Biodiversity benefits from a six year ripaMn agroforestry project. Proceedings of the Society of Arnerican Foresters National Convention. Oct. 4-8. 1997. Memphis, Tennessee. pp. 163-1 66.

Statistics Canada. 1997. Agricultural profile of Ontario, 1996 Census of Agriculture. Statistics Canada, Agriculture Division, Ottawa. pp. 223.

StatsSoft Inc. 1998. Statistica for Windows [cornputer manual]. Tulsa. Oklahoma.

Stamps, W.T. and M. J. Linit. 1998. Plant diversity and arthropod communities: Implications for temperate agroforestry. Agroforestry Systems. 39(1): 73-89.

Stamps, W.T. and M.J. Linit. 1999a. The problem of experirnental design in temperate ag roforestry . Agroforestry Systems. 44(2-3): 1 87-1 96.

Stamps, W.T., Woods, T.L. and M.J. Linl. 1999b. Arthropod diversity in an agroforestry system of black walnut and forage crops. In: Meeting and programs abstracts of the Entomological Society of America annual meeting. Decernber 12-1 6, 1999. Atlanta. Georgia, United States.

Stamps, W.T.. Woods. T.L. and M.J. Linit. 2000. Plant divemty and arthropod communities: an example from agroforestry. In: Meeting and program abstracts of the 2000 joint annual meeting of the Societe d'Entomologie du Quebec, Entomological Society of Canada and the Entomological Society of America. Decernber 3-5, 2000. Montreal, Quebec, Canada.

Stein,W. 1986. Dispersal of insect of public health importance. In: Danthanarayana. W. (ed.) lnsect Flight : dispersal and migration. Springer-Verîag, New York. pp. 197-234.

Stelzl, M. and D.Devatak. 1999. Neuroptera in agricultural ecosystems. Agriculture, Ewsystems and Environment. 74: 305-321.

Stinner, B.R.,Krueger. H.R. and D.A. McCartney. 1986. Insecticide and Mage effects on pest and non-pest arthropods in corn agroecosystems. Agriculture, Ecosystems and Environment. 15(1): 1 1-21.

Page 126: efek tumpangsari thdp keragaman arthropod

Stinner, B.R. and G.J. House.1990. Arthropods and other invertebrates in conservation- tillage agriculture. Annual Review of Entomology. 35:299-318.

van Straalen. N.M. 1997. Community structure of soi1 arthropods as bioindicaton of soi1 heaith. In: Pankhurst. C. Doube. B.M., Gupta. V. (4s.) Biological lndicators of Soil Health .CAB International. London. pp. 235-263.

Str0ng.D. R. Lawton, J.H. and T.R.E. Southwood. 1984. lnsects on Plants: community patterns and mechanisms. Blackwell Scientific. Oxford. pp. 31 3.

Sutton. S.L. 1972 . Woodlice. Ginn and Company Ltd., London. pp.143.

Svensson, B., Lagerlof, J., and B.G. Svensson. 2000. Habitat preferenœs of nest- seeking bumble bees ( Hymenoptera: Apidae) in an agricultural landscape. Agricutture, Ecosystems. and Environment. 77(3): 247-255.

Swift. M.J., J. Vandermeer, P.S. Ramakrishnan. J.M. Anderson, C.K. Ong, and B. A. Hawkins. 1996. Biodiversity and agroecosystem fundion. In: Mooney. H .A., Cushman, J.H.. Medina, E.. Sala, O.E., and E.D. Schuke (eds.) Functional Roles of Biodiversity: a global perspective. John Wiley and Sons Ltd. pp. 261-298.

Tahvanainen, J.O. and R.B. Root.1972. The influence of vegebtional diversity on the population ecology of a specialized herbivore, Phyllotreta c ~ c h m (Coleoptera: Chrysomelidae). Oecologia. 10:321-346.

Thevathasan, N.V. and AM. Gordon. 1 998. Poplar leaf biomas distribution and nitmgen dynamics in a poplar-badey intercropped system in southem Ontairo, Canada. Agroforestry Systems. 37(1):79-90.

Thomas, C.F.G. and E.J.P. Marshall. 1999. Arthropod abundance and diversity in differentiy vegetated marg ins of arable fields. Agriculture, Ecosysterns and Environment. 72(2): 131-144.

Thornas,M.B.. Wratten, S. D. and N.W.Sotherton. 1992. Creation of 'island' habitats in familand to manipulate populations of beneficial arthropods: predator densities and species composition. Journal of Applied Ecology. 29:524-531.

Tonhasca Jr.. A. and D.N. Byme. 1994. The effects of crop diversification on herbivorous insects: a meta-analysis approach. Ecological Entomology. 19: 239-244.

Towne~~H.1972. A light-weight Malaise trap. Entomological News. 83239-247.

Tschamtke, T. 2000. Parasitoid population in the agricuitural landscape. In: Hochberg, M.E. and A.R. Ives (eds.) Parasitoid population biology. Princeton University Press, W O O ~ S ~ O C ~ , UK. pp. 235-253.

Page 127: efek tumpangsari thdp keragaman arthropod

115 United States Deparbnent of Agriculture (USDA). 1997. Alley Cropping. Conservation Practice Job Sheet no. 31 1. Natural Resource Conservation SeMœ (NRCS). USDA office of communications, Washington, D.C. pp. 4.

United States Department of Agriculture (USDA). 2000. Agroforestry: working trees for agriculture. Working Trees Brochures. pp6. Webpage:~.unl.edulnac/brochuresEwtal index. htrnl

Unnih ,T. R. and R.H. Messing -1 993. lntraspecific biodiversity in Hymenoptera: implications for conservation and biological wntrol. In: Lasalle, J. and I.D. Gauld (eds.) Hymenoptera and Biodivenity. CAB International, Wallingford, U.K. pp. 27-52.

Varchola, J.M. and J.P. Dunn. 1999. Changes in ground beetle (Coieoptera: Carabidae) assemblages in farming systems borderd by complex or simple roadside vegetation. Agriculture, Ecosystems, and Environment. 73(1): 4149.

Vickery, V.R and D.K. Kevan. 1986. The Grasshoppers, Crickets, and Related lnseds of Canada and Adjacent Regions. The lnsects and Arachnids of Canada, pt. 14. Bisosystematics Research Institute, Agriculture Canada. Canadien Govemment Publishing Centre, Ottawa. pp. 91 8.

Vohland, K. and G. Schroth.1999. Distribution patterns of the litter macrofauna in agroforestry and monoculture plantations in central Amazonia as affected by plant speices and management. Applied Soil Ecology. 13:57-68.

Wallace,R.A., Sanders, G.P. and R.J.Ferl. 1991. Biology:the science of life. 3d edition. Harpercolins Publishers, New York. pp. 1246.

Ward, K.E. and R.N. Ward. 1999. Diverstty and abudance of carabid beetles in short- rotation planting of sweetgum, corn and swtichgrass. In: The poster abstracts of the sixth conference on agroforestry in North America. June 12-1 6, 1 999, Hot Springs, Arkansas. pp. 39.

Wardle, D.A., Giller,K.E. and G.M. Barker. 1999. The regulation and functional significance of soi1 biodivenity in agroeccwystems. In: Wood, D. and J.M. Lenne (eds.) Agrobiodiversity: Characterization, Utilization and Management. CAB International Publishing. Wallingford, UK. pp. 87-121.

Weisser. W.W., Volkl, W. and M.P. Hassell. 1997. The importance of adverse weather conditions for behaviour and population ecology of an aphid parasitoid. The Journal of Animal Ecology. 66: 386400.

Wilcox. J. A. 1979. Leaf Beetle Host Plants in Northeastem North America (Coleoptera, C hrysomelidae). Biolog ical Research Institute of America. World Natural History Publications, Kinderhook, New York. 30 pp.

Williams, P.A.(ed.). 1991. Agroforestry in North America. Proceedings of the First Conference on Agroforestry in North America. 13-16 August 1989. University of Guelph,Guelph, Ontario, Canada.

Page 128: efek tumpangsari thdp keragaman arthropod

Wlliams, P.A. and A.M. Gordon. 1992. The potential of intercropping as an alternative land use system in temperate Norai Arnerica. Agroforestry Systems.19: 253-263.

W~lliams, P.A. and A.M. Gordon. 1995. Microclimate and soit moisture effects of three intercrops on the rows of a newly-planted intercropped plantation. Agroforestry Systems. 29: 285302.

Williams, P.A., Koblents, H.and A.M. Gordon. 1996. Bird Use of an lntercropped Corn and Old Field in Southem Ontario, Canada. In: Ehrenreich, John H., Ehrenreich Dixie L. and Hamy W. Lee (eds.) Growing a sustainable Mure. Proceedings: Fourth North American Agroforestry Conference, July 1996, Boise, Idaho.

Williams, P.A., Gordon. A.M.. Garrett, H.E., and L. Buck. 1997. Agroforestry in North Arnerica and its role in fanning systems. In: Gordon, Andrew M. and Steven M. Newman (eds.) Temperate Agroforestry Systems. CAB International, Wallingford, UK. PP. 9-84.

Williams, P. H. and K. J. Gaston 1993. Measuring more of biodiversity: can higher-taxon richness predict wholesale species richness? Biological Conservation. 67:211-217.

Winter, J.P., Voroney, R.P. and DA. Ainsworth. 1990. Soil microarthropods in long-term no-tillage and conventional Mage corn produdion. Canadian Journal of Soil Science. 70(4): 641-653.

Wratten, S.D. and H.F. Van Emden. 1995. Habitat management for enhanced activity of natural enemies of insect pests. In: D.M. Glen (ed.) Ecology and lntegrated Famiing Systems. John Wiley and Sons, U.K. pp. 117-145.

Xu, W. and J. A. Mage. 2001. A review of concepts and criteria for assessing agroecosystem heaith including a preliminary case study of southem Ontario. Agriculture, Ewsystems, and Environment. 83(3): 215-233.

Zhang, P. 1999. Nutrient inputs from trees via throughfall, stemflow and litterfaIl in an intercropping system. MSc thesis. University of Guelph, Guelph, Ontario, Canada. pp. 1 02

Page 129: efek tumpangsari thdp keragaman arthropod

Appendices

Appendix 1 - Number of arthropods in each orderlclass using pan traps during June 1998 from Norway spruce and black walnut sites within the intercroped agroforestry and corn monoculture sites, at the Guelph Agricultural Research Station (n-60).

Arthropod lntercropping agroforestry Monoculture Total % of orders /classes total

sample Walnut Norway

spruce Araneae 65 46 21 132 0.92 Chilopoda Coleoptera Collembola Demapte ra Di plopoda Diptera Hemiptera Homoptera Hymenoptera lsopoda Lepidoptera Odonata Opiliones Orthoptera Psocoptera

NO. of orders 13 13 11 15 No. of classes 2 2 2 2 No. of individuals 5,788 3,958 4,526 14,272 100.00

Page 130: efek tumpangsari thdp keragaman arthropod

Appendix 2 - Number of arthropods in each order using Malaise traps during JuneSeptember 1999, from Nomay spruce and black walnut sites within the intercropping agroforestry and corn monoculture study sites, at the Guelph Agricultural Research Station (nt48).

Arthropod lntercropping agroforestry Monoculture Total % of orders total

sample Walnut Norway spruce

Araneae 12 36 38 86 0.27 Coleoptera Collem bola Demiaptera Diptera Hemiptera Homoptera Hymenoptera Lepidoptera Neuroptera Odonata Opiliones Orthoptera Pscocoptera Thysanoptera 17 99 156 272 0.85 No. of orders 14 15 15 15 No.of individuals 9.354 13.-884 8.821 32.059 100.00

Page 131: efek tumpangsari thdp keragaman arthropod

Appendix 3 - Number of arthropods in 61 selected families and 2 selected orders that are representing the parasitoid, predator, pollinator, detritivore and herbivore functional guilds; caught in June- September 1999 in the intercropping agroforestry Norway spruce and the corn monoculture study site, at the Guelph Agricultural Research Station (~32).

Arthropod Selected family Guild lntercropping Monoculture Total % of orders and order chssification agroforestry overall

total Araneae Araneae Predatot 36 38 74 0.66 Coleoptera

Collembola

Diptera

Hemiptera

Homoptera

Carabidae C hysomelidae Coccinellidae Entornobryidae Sminthuridae Asilidae Dolichopodidae Pipunculidae Syrphidae Tachinidae Anthocoridae Lygaeidae Miridae Nabidae Red uviidae Ap hidae Cercopidae Cicadellidae Fulgoroidae

Hymenoptera Andrenidae Aphelinidae Apidae Bethylidae Braconidae Ceraphronidae Chalcididae Chrysididae Colletidae Diapriidae Dryinidae Elasmidae Encyrtidae Eucharitidae Eucoilidae

Predator Herbivore Predator Detritivore Det ritivore Predator Predator Parasitoid Predator Parasitoid Predator Herbivore Herbivore Predator Predator Herbivore Herbivore Herbivore Herbivore Pollinator Parasitoid Pollinator Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Pollinator Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid Parasitoid

Page 132: efek tumpangsari thdp keragaman arthropod

Appendix 3 cont'd.

Arthropod Selected family Guild Intercropping Monoculture Total % of orders and order classification agroforestry overall

total Hymenoptera Eulophidae Parasitoid 138 65 203 1.81 cont'd . Eupelmidae Parasitoid 16 3 19 0.17

Eurytomidae Parasitoid 36 8 44 0.39 Figitidae Pa rasitoid O 1 1 0.01 Formicidae Predator 69 59 128 1.14 Halictidae Pollinator 60 22 82 0.73 lchneumonidae Parasitoid 217 36 253 2.26 Megachilidae Pollinator 1 O 1 0.01 Megaspilidae Pa rasitoid 9 22 31 0.28 Mutilidae Predator 41 17 58 0.52 Mymaridae Pa rasitoid 257 175 432 3.86 Platygastridae Parasitoid 57 8 65 0.58 Pompilidae Predator 255 92 347 3.10 Proctotrupidae Parasitoid 3 O 3 0.03 Pterornalidae Pa rasitoid 84 34 118 1.05 Scelion idae Parasitoid 376 288 664 5.93 Scoliidae Pa rasitoid 3 25 28 0.25 Sphecidae Predator 71 27 98 0.87 Tenthredinidae Herbivore 1 O 1 0.01 Tiphiidae Parasitoid 2 2 4 0.04 Trichog rammatidae Parasitoid 10 14 24 0.21 Vespidae Predator 32 47 79 0.71

Lepidoptera Noctuidae Herbivore 25 13 38 0.34 Pyralidae Herbivore 8 6 14 0.12

Neuroptera Chrysopidae Predator 58 7 65 0.58 Hemerobiidae Predator 44 12 56 0.50

Opiliones Palpatores Detritivore 38 4 42 0.37 Orthoptera Acrididae Herbivore 12 4 16 0.14 Number families from selected list 60 55 61 Number of orders from selected list 2 2 2 Number of individuals 7,005 4,197 11,20 100

2