Plant - Insect Interactions

Seeing The Universe From An Insect’s Perspective

T’ai Roulston

The problems faced by animals that eat plant products

Get FoodFind MatesAvoid Being Eaten

The problems faced by plants

Get PollinatedDisperse SeedsAvoid Being Eaten

Insect Plant

How Insects Affect Plants

Positive

Negative

Pollination

Herbivory

Insect Plant

How Insects Affect Plants

Positive

Negative

Frugivory - seeddestruction

Photo:Benoit Guenard

Seed dispersal

Insect Plant

How Insects Affect Plants

Positive

Negative

Predation/Parasitism

Insect Plant

How Insects Affect Plants

Positive

Negative

Photo: Marin Rice

jeffcogardener.blogspot.com

cirrusimage.com

Anti-predatordefense

Insect Plant

How Insects Affect Plants

Positive

Negative

Spread disease

Photo: Jude Boucher

Cucurbit Yellow Vine Diseasesquash bugs

Plant Performance

Insect 1

Insect 4Insect 3

Insect 2

Net Effect = Sum of Interactions

Implications for both agriculture and ecosystems

Physalis longifolia study systemMary McCauley, Berea College (2004); Maggie Triska, Viterbo University (2005);Jacob Elstein, Virginia Tech (2005); Cedric Jones, Howard University (2006);Brandon Lingbeek, Calvin College (2007); Linnea Meier, Earlham College (2008);Alysia Soper, Luther College (2008); Ricky Rivera, UPR-Bayamon (2009); Stephanie Cruz-Maysonet, UPR-Bayamon (2010)

Seed Production

Flower Production

Fruit Induction

FruitMaturation

Stored Energy

SpecialistGeneralists

Why might specialists be important?

Specialist foraging strategy or generalist strategy if the generalist acts as a temporary specialist

Generalist foraging strategy whenseveral acceptable hosts

Tracking Pollinators

• Recapture and movement of specialist and generalist pollinators of Physalis during 2004 and 2005

Type # marked # recaptured proportion # movementsSpecialist 76 21(53) 0.28 16Generalists 24 0 0 0Specialist* 82 27(43) 0.33 1Generalists* 58 0 0 0

Plot Visits per Survey Hour for Each Species

Colletes Lasiogl. Augochl. Epeolus Bombus

Vis

its

pe

r S

urv

ey H

ou

r

0

1

2

3

4

5

6

7

July 7-14, 2004 July 15-22, 2004 July 23-30, 2004

Number of flowers visited per plot visit per species

Species

Colletes Augochl Lasiogl. Epeolus

Flo

we

rs v

isit

ed

pe

r p

lot

vis

it

0

1

2

3

4

5

6

Colletes Lasioglossum Augochlorinae

Pro

po

rtio

n F

ruit

s In

itia

ted

fro

m S

ing

le V

isit

s

0.0

0.2

0.4

0.6

0.8

1.0

p < 0.05

Fruit Initiation From Single Visits

Pollinator Conclusions

The specialist prevails in

abundanceflowers visitedpollination efficiencypollen dispersal

Seed Production

Flower Production

Fruit Induction

Pollen Deposition

FruitMaturation

Stored Energy

Pollinators

Initially Interested in Pollination

Week

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Proportion Yearly Total0.0

0.1

0.2

0.3

0.4

0.5

Lema daturaphila larvae

Flowering

What Governs Presence of Herbivore?

Susceptible Genotypes? Induced defenses? Predation?

Survival to Mature Larva of 10 Lema Placed on 10 Caged and 10 Uncaged Plants

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NOTE TO SELF --THESE PICTURES DO NOT DISPLAY

REU student Brandon Lingbeek

One cause of mortality to Lema eggs

Q1: Early season decline not explained by late season predators or parasites.

Nocturnal predators? Plant is saved by whatever is controllingearly herbivores.

Seed Production

Flower Production

Fruit Induction

Foliar Herbivory

Frugivory

Pollen Deposition

FruitMaturation

Stored Energy

Parasitism

Predation

Predation

Interaction web forPhysalis longifolia

Parasitism

Development of Symmetrischema sp.

Seed Production

Flower Production

Fruit Induction

Foliar Herbivory

Frugivory

Pollen Deposition

FruitMaturation

Stored Energy

Parasitism

Predation

Predation

Interaction web forPhysalis longifolia

Parasitism

Florivory

Part 2. How Do Plants Affect Insects?

Bee Diversity and Plant Utilization Patterns

20,000 spp worldwide 140 (so far) at Blandy

Center of Diversity: arid areas –southwestern USA, Mediterranean

Diet: pollen and nectar

Development of the sweat bee Lasioglossum zephyrum

Variation in Pollen Chemistry

Constituent Max Min

% Starch 23.7 0

Calories/g 6750 4407

% Protein 60 2.5

Amino acid variation: ??

Toxicity??

Ongoing Research: Understand the plant traits that influenceinsect foraging decisions, and the results of those foragingdecisions on insect development

What Is Known About Pollen - Bee Interactions?

Extremely importantPollen varies in many waysBees make flower choices based on

accessibilitynectar rewardfloral colorfloral odor

Q2: Do bees recognize quality and adjust choice?

What are the characteristics of quality? What plants (either natives or invasives) may best supportwild pollinator populations?

Specific Possible Avenues for Inquiry

Herbivory on wild tomatillo:

What early season factors protect the plantfrom an enemy that could destroy all of it?

Foraging Cues:

What pollen traits influence larval development and body sizein bees? Do bees recognize them?

The End

Research Areas

Why pollinators choose the plants they doNutritional quality of pollen

The implications of foraging choices of pollinatorson success of their host plants

Why herbivores choose their host plants

What governs herbivore populations

Potential Applications

Understanding how to promote wild pollinators in agricultureUnderstanding ecosystem level processes to control pests