CSIRO PUBLISHING

www.publish.csiro.au/journals/mfr Marine and Freshwater Research, 2008, 59, 897–901

The effects of leaf litter characteristics on feeding andfitness of a tropical stream shredder, Anisocentropusmaculatus (Trichoptera : Calamoceratidae)

Aggie O. Y. LiA and David DudgeonA,B

ADivision of Ecology & Biodiversity, School of Biological Sciences, The University of Hong Kong,Pokfulam Road, Hong Kong SAR, PR China.

BCorresponding author. Email: ddudgeon@hkucc.hku.hk

Abstract. Plant diversity is high in the tropics, resulting in leaf litter of differing quality in streams that may affect feedingand fitness of shredders. The effects of leaf toughness and nitrogen content on feeding and fitness (pupal weight) of aHong Kong shredder, Anisocentropus maculatus (Trichoptera : Calamoceratidae), were investigated in laboratory feedingtrials that included leaves from five plant species with contrasting characteristics. Leaf toughness adversely affected thefeeding rates and fitness of A. maculatus. Feeding rates on tough leaves (Indocalamus sinicus and Pandanus furcatus)were >96% lower compared with soft leaves (Ficus fistulosa and Liquidambar formosana), whereas feeding rates onmoderately tough leaves (Melaleuca quinquenervia) were intermediate. Larval mortality was >7 times higher on tough(78–100%) than softer leaves (0–11%), and resulting pupae were >71% lighter. Leaf nitrogen content was not a gooddeterminant of feeding or fitness of A. maculatus, but larvae appeared to eat greater amounts of nitrogen-poor leaves tocompensate for lower food quality. Leaf toughness was the primary determinant of feeding and fitness of A. maculatus,and the refractory leaves of many tropical plants could account for the scarcity of shredders in tropical streams.

Additional keywords: Hong Kong, leaf toughness, nitrogen content.

Introduction

Macroinvertebrate shredders consume leaf litter and othercoarse particulate organic matter (CPOM >1 mm in diameter:Cummin 1973; Cummin and Klug 1979), and their importance inlitter breakdown in north-temperate streams has been well doc-umented (Cuffney et al. 1990; Graça 2001; Hieber and Gessner2002). Shredder feeding rate tends to be inversely related to leaftoughness (Albariño and Balseiro 2001; Motomori et al. 2001)and positively related to nitrogen content (Pearson and Tobin1989). Preference tests have shown that shredders select leaveswith high nitrogen content (Iversen 1974; Rincón and Martínez2006) and low toughness (Parkyn and Winterbourn 1997). Pre-sumably, consumption of better quality food increases shredderfitness in terms of survivorship and/or growth rates (Arsuffi andSuberkropp 1986; Canhoto and Graça 1995; Quinn et al. 2000).

Plant species diversity in the tropics is high and leavesgenerally have better physical and chemical defenses againstherbivores than their temperate counterparts (Coley and Aide1991; Coley and Barone 1996), resulting in a variety of littertypes of varying food quality (Stout 1989; Bastian et al. 2007).Much of this litter may be unpalatable and refractory to streamdetritivores, which may reduce shredder feeding and abundance(Irons et al. 1988; Pearson andTobin 1989; Jacobsen et al. 2008).Our goal was to investigate the relationship between litter qualityand tropical shredders by examining the effects of leaves withdifferent combinations of toughness and nitrogen content on thefeeding rates and fitness in terms of pupal weight (and, hence,

fecundity: Feminella and Resh 1990; Honek 1993) of Anisocen-tropus maculatus Ulmer, 1926 (Trichoptera : Calamoceratidae).We expected that shredder feeding and fitness would be pos-itively related to leaf litter quality (nitrogen content) and/orinversely related to leaf toughness.

Materials and methods

Anisocentropus maculatus is the most common obligate shred-der in Hong Kong streams (Li and Dudgeon 2008), and thegenus is widespread in tropical Asia and Australia (Pearsonet al. 1989; Nolen and Pearson 1993; Dudgeon 1999). The lar-vae of this caddisfly make portable leaf cases by cutting andsticking two pieces of leaves together. A larger dorsal piece ofleaf shields the head and thorax of the larva and the abdomenis enclosed within the chamber between the dorsal piece anda smaller ventral piece (Dudgeon 1999). Larvae of Anisocen-tropus maculatus were collected in Tai Po Kau Forest Stream(TPKFS; Universal Transverse Mercator grid reference = 50QKK 096 823; 22◦25′N, 114◦11′E) in the central New Territo-ries of Hong Kong. TPKFS is an unpolluted third-order streamwith soft, nutrient-poor water and low conductivity, draininga secondary forest mainly composed of trees native to SouthChina. The stream channel (altitude ∼180 m asl) was domi-nated by boulders as well as cobbles and gravel, and was heavilyshaded (>70% cover) by riparian vegetation. Individual lar-vae of similar size (mean length of the ventral portion of thecase = 13.5 mm, range = 12.6–15.0 mm: mainly 4th instar) were

© CSIRO 2008 10.1071/MF08120 1323-1650/08/100897

898 Marine and Freshwater Research A. O. Y. Li and D. Dudgeon

Table 1. Characteristics of the five leaf species used in the feeding trialsDifferent letters indicate a significant interspecific difference at P < 0.05 (ANOVA plus Tukey test). F, Ficus fistulosa; I, Indocalamus sinicus; L, Liquidambar

formosana; M, Melaleuca quinquenervia; P, Pandanus furcatus

Species Family Absolute Specific Nitrogen Notesstrength strength content (%DW

(g mm−2) (g mm−3) nitrogen)

Liquidambar formosana Hance Hamamelidaceae 185.5 ± 8.5a 1194.6 ± 83.8a 1.2 ± 0.1a Common native tree and widelyplanted, deciduous

Ficus fistulosa Reinw. ex Blume Moraceae 195.0 ± 17.2a 992.1 ± 84.5a 2.2 ± 0.1c Common native riparian treein Hong Kong, evergreen

Melaleuca quinquenervia (Cav.) Myrtaceae 616.0 ± 41.7b 2091.8 ± 126.2b 1.7 ± 0.1b Commonly planted exotic treeS.T. Blake species, evergreen

Indocalamus sinicus (Hance) Poaceae 643.5 ± 24.4b 4246.7 ± 171.6c 1.5 ± 0.1b Common native bamboo onNakai Hong Kong hillsides, evergreen

Pandanus furcatus Roxb. Pandanaceae 1473.6 ± 75.8c 2614.5 ± 178.1b 1.0 ± 0.1a Common native tree growingalong streams, evergreen

Ranking L = F < M = I < P F = L < M = P < I P = L < I = M < F

collected and subsequently acclimatised in aerated aquaria for7 days (temperature = 20–23◦C; photoperiod = 12 : 12) with amixture of leaf litter from TPKFS provided as food.

Mature leaves for feeding trials (Table 1) were collected fromvarious plants in Tai Po Kau Nature Reserve or Lung Fu ShanCountry Park, Hong Kong, except for freshly abscised leavesof deciduous Liquidambar formosana that were taken from theforest floor. Leaf toughness was measured using a penetrometer(School of Tropical Biology, James Cook University, Australia)that consisted of two blocks (for holding the leaves) with a die forpenetration of a 0.79-mm-diameter punch connected to a plat-form for weight addition. Leaf toughness was given in terms ofabsolute strength (AS) and specific strength (SS): AS =W/A,and SS =W/(A ×T), where W is the weight needed to pen-etrate the leaf, A is the punch area and T is the thickness ofthe leaf (measured using a digital calliper). Leaf nitrogen con-tent was measured at the University of California, Davis StableIsotope Facility (Department of Plant Sciences, University ofCalifornia, Davis) using a PDZ Europa 20–20 isotope ratio massspectrometer (Sercon Ltd, Cheshire, UK).

Ten plastic chambers (16.5 × 11.5 × 6.5 cm; covered with4-mm mesh) were placed in an aerated glass tank (60 × 40 ×40 cm). Each of five chambers contained three individuals ofAnisocentropus maculatus and ∼1 g of one of the five leafspecies; an additional five chambers with one leaf species in each(without A. maculatus) were added as controls. This arrange-ment was replicated six times in six tanks (n = 6 per treatment).Dechlorinated tap water was used and half the water in each tankwas replaced on alternate days.

Leaves were air dried to constant weight, weighed and soakedin tap water for 7 days before being fed to the shredders. Theywere replaced at least once each week to ensure that food was inexcess and that toughness and nitrogen content of the leaves werefairly constant. Shredders were placed on the newly-added leavesafter they were removed from the old leaves. They were checkeddaily for pupation or death, and feeding trials lasted for 81 daysuntil all shredders had pupated or died. Any pupating or deadindividuals were removed from the chambers. Pupae were ovendried (60◦C, 48 h), weighed, ashed (500◦C, 4 h) and reweighed

to determine ash-free dry weight (AFDW). Uneaten leaves col-lected throughout the experiment were oven dried to give totalleaf mass loss and, hence, shredder feeding rates. Leaves in thecontrols were also replaced at the same time as for the treatments.Ten sets of pre-weighed air-dried leaves (∼1 g) were ashed toprovide conversion factors from initial air-dry weight to AFDW,and nine sets of oven-dried leaves from each feeding treatmentand control were likewise treated to provide conversion factorsfrom final dry weight (DW) to AFDW.

Mean daily per-capita feeding rates and mean total amountsof leaves consumed per individual shredder before pupationwere calculated for each replicate chamber in each treatmentas follows:

Feeding rate =([

W0−Wt

W0

]s− ∑n

i=1

[W0−Wt

W0

]i

/n)

T1 + T2 + T3× [W0]s

Amount of leaves consumed = feeding rate × T

where W0 is the initialAFDW of the leaves,Wt is the finalAFDWof the leaves, n is the number of replicates, subscript ‘s’ rep-resents the feeding treatment, subscript ‘i’ represents replicatecontrol treatments (1 − n) without shredders, T is the mean num-ber of days spent feeding before pupation (where individuals thatdied during trials were excluded) and T1, T2 and T3 are the num-ber of days shredders 1, 2 and 3, respectively, fed in the samechamber before pupation or death. Leaf absolute strength, spe-cific strength and nitrogen content were compared among leafspecies by one-way ANOVA followed by Tukey tests, and cor-relation analyses were undertaken among these parameters ofleaves. Feeding trial results were analysed by a block designANOVA (each glass tank representing one block, treatments asa fixed factor) followed by Tukey tests; mean values of threeindividual shredders for each replicate chamber were used forthe comparisons to minimise any effect due to variation amongindividual shredders (thus there were six replicates in each treat-ment). All parametric tests were undertaken using SPSS 15.0(SPSS Inc., Chicago, IL). Log10-transformations were applied

Feeding by a tropical stream shredder Marine and Freshwater Research 899

Table 2. Feeding rates, amounts of leaves eaten, pupal weight and time taken for pupation (mean ± s.e.), as well as mortality andtime of death (mean + range in parentheses) of Anisocentropus maculatus larvae reared on different leaf species

Different letters indicate a significant interspecific difference at P < 0.05 (ANOVA plus Tukey test). – = no pupation/no mortality

Leaf species Feeding rate Amount eaten Pupal weight Pupation time Mortality Death time(mg AFDW (mg AFDW (mg AFDW) (days) (%) (days)

capita−1 d−1) pupa−1)

Liquidambar formosana 12.5 ± 0.5c 299.4 ± 19.5c 10.7 ± 0.6b 24.1 ± 1.1a 0 –Ficus fistulosa 10.7 ± 0.5c 212.0 ± 6.9b 11.7 ± 0.5b 19.9 ± 0.6a 0 –Melaleuca quinquenervia 7.2 ± 0.5b 171.2 ± 11.8b 10.4 ± 0.6b 23.9 ± 0.6a 11 11.5 (7–16)Indocalamus sinicus 0.1 ± 0.2a 4.1 ± 8.3a 3.0 ± 0.5a 36.0 ± 5.0b 78 40.4 (7–77)Pandanus furcatus 0.4 ± 0.1a – – – 100 33.8 (4–81)

AFDW, ash-free dry weight.

to the data wherever transformations normalised the datasets orreduced the difference in variance among datasets.

Results and discussion

Toughness and nitrogen content differed significantly amongleaf species (absolute strength: F4,55 = 204.26, P < 0.001;specific strength: F4,55 = 76.98, P < 0.001; nitrogen content:F4,25 = 54.98, P < 0.001; see Table 1), and these parameterswere not correlated with each other. Shredder feeding rates were>96% lower on the tough leaves of Indocalamus sinicus and Pan-danus furcatus relative to the soft leaves of Ficus fistulosa andLiquidambar formosana (ANOVA, F4,20 = 251.80, P < 0.001;Table 2), whereas feeding rates on the moderately tough leaves ofMelaleuca quinquenervia were intermediate. Although interac-tion between the three individuals of shredders in each chambermight have affected the per-capita feeding rates (see Boyero andPearson 2006), it would not have affected the comparison offeeding rates among leaf species. The negative effect of leaftoughness on shredder feeding matches the ranking of break-down rates of leaf species within litter bags (4-mm-mesh) inTPKFS (Li et al. 2008), although it should be stressed that shred-ders are not abundant in Hong Kong streams (Dudgeon and Wu1999; Li and Dudgeon 2008).

Leaf toughness adversely affected the fitness of Anisocentro-pus maculatus. All individuals feeding on Ficus fistulosa andLiquidambar formosana survived to pupate, and mortality ofshredders reared on the moderately tough leaves of Melaleucaquinquenervia was low (11%). None of the larvae that werefed Pandanus furcatus survived to pupation (100% mortality),and mortality of larvae reared on similarly tough Indocalamussinicus leaves was also high (78%). Pupal weight and time topupation did not differ among larvae that were fed Ficus fis-tulosa, Liquidambar formosana and Melaleuca quinquenervia,but were (respectively) higher and shorter than in the Indocala-mus sinicus treatment (pupal weight: F3,13 = 43.45, P < 0.001;time to pupation: F3,13 = 8.69, P = 0.02; Table 2). The few ofthese larvae that survived to pupation took, on average, 12–16days longer to pupate, and pupae were no more than 29% of theweight of pupae of larvae fed softer leaves (Table 2).

Reductions of shredder feeding and fitness owing to leaftoughness have been reported in other studies (Canhoto andGraça 1995; Albariño and Balseiro 2001; Motomori et al. 2001)

although this relationship is not seen in all studies (Irons et al.1988; Nolen and Pearson 1993; Jacobsen and Friberg 1995), insome cases, possibly owing to the overriding effects of leaf nitro-gen content and condensed tannins on shredder feeding (Ironset al. 1988). Surprisingly, nitrogen content was not a good deter-minant of feeding rates and fitness ofAnisocentropus maculatus,although shredders have been reported to select nitrogen-richleaves (Irons et al. 1988; Rincón and Martínez 2006) leadingto faster growth (Iversen 1974). Feeding rates and pupal weightof larvae that were fed Indocalamus sinicus were low, despiteits relatively high nitrogen content (1.5% DW nitrogen) com-pared with Liquidambar formosana (1.2% DW). This accordswith a study of the Australian Anisocentropus species, whichconsumed little para grass (Urochloa mutica) despite its highnitrogen content (Clapcott and Bunn 2003). There was no differ-ence in the pupal weights of larvae that were fed the relatively softleaves of Ficus fistulosa, Liquidambar formosana and Melaleucaquinquenervia, despite significant interspecific differences innitrogen content (1.2–2.2% DW). Although the nitrogen contentof leaves may vary during breakdown, leaves were replaced atleast once per week during our feeding trials to help ensure thatnitrogen content of leaves remained consistent, and there was noevidence that conditioning by microbes would have affected theinterspecific differences in leaf nitrogen content. We suspect thatany effect of nitrogen content was probably overridden by theeffect of leaf toughness, which might have acted as a physicalbarrier to shredder feeding (see Albariño and Balseiro 2001).

Shredders reared on Indocalamus sinicus consumed thesmallest amounts of leaves before pupation (F3,13 = 54.63,P < 0.001; Table 2). When only soft leaves were considered,shredders reared on relatively nitrogen-poor Liquidambar for-mosana ate more leaves before pupation than those fed Ficusfistulosa or Melaleuca quinquenervia (Table 2). This ranking ofquantities of food eaten is inversely proportional to leaf nitro-gen content, and larvae might have increased their consumptionof low-quality food in order to maintain growth and develop-ment, as reported in studies of shredders elsewhere (Iversen1974; Friberg and Jacobsen 1999; Albariño and Balseiro 2001).

The present study suggests that leaf quality was more impor-tant than the origin (native/exotic) of the leaves in determiningthe feeding rates and fitness of Anisocentropus maculatus, sinceindividuals feeding on exotic Melaleuca quinquenervia (mod-erately tough) had feeding rates and fitness within the range of

900 Marine and Freshwater Research A. O. Y. Li and D. Dudgeon

native plant species. The lack of association between shreddersand native leaves has also been reported in a preference testusing the conoesucid caddisfly, Olinga jeanae, in New Zealand(Parkyn and Winterbourn 1997) where soft leaves were preferredand tough leaves remained uneaten regardless of their origin.

Although tropical and temperate shredders exhibit similarfeeding patterns in the laboratory (Graça et al. 2001), shred-ders appear to be scarce in tropical streams (see citations inDudgeon 2000; Jacobsen et al. 2008). Leaf defenses evolved todeter terrestrial herbivores (Coley and Barone 1996) can affectshredder feeding and fitness (Irons et al. 1988; Canhoto andGraça 1995; Rincón and Martínez 2006), and may have theconsequence that shredders play a minor role in litter break-down in tropical streams (Dudgeon and Wu 1999; Mathuriau andChauvet 2002) where the contribution of microorganisms maybe more substantial (Irons et al. 1994). Secondary compoundswere not considered in the present study, but our results nonethe-less revealed clear effects of leaf characteristics on shredderfeeding and fitness, with toughness (a physical defence againstherbivory) overriding the effect of nitrogen. Since leaves oftropical evergreen plants are likely to be more diverse (sincethere are more species) and generally tougher than those oftemperate deciduous plants (Coley and Aide 1991; Coley andBarone 1996), we hypothesise that these leaves with high tough-ness would impose a greater constraint on shredder feeding andabundance in some tropical streams than in streams at temper-ate latitudes. This difference in plant defenses may underliethe apparent relative scarcity of shredders in tropical lowlandstreams (Jacobsen et al. 2008; Li and Dudgeon 2008).

AcknowledgementsWe are grateful to Dr Niall Connolly and Dr Luz Boyero (James Cook Uni-versity) for providing the penetrometer used in this study, as well as to DrBoyero and two anonymous referees for their constructive comments on themanuscript. Ms Lily Ng provided invaluable laboratory support. A permitfor collection of plants/animals was issued by the Agriculture, Fisheries andConservation Department of the Government of the Hong Kong SpecialAdministrative Region, China. The work was partially supported by a grantfrom the Research Grants Council of Hong Kong Special AdministrativeRegion, China (Project No. [HKU] 7509/06M), and by a postgraduate stu-dentship awarded to A. O. Y. Li during her M.Phil. studies at the Universityof Hong Kong.

ReferencesAlbariño, R. J., and Balseiro, E. G. (2001). Food quality, larval consumption,

and growth of Klapopteryx kuscheli (Plecoptera: Austroperlidae) from asouth Andes stream. Journal of Freshwater Ecology 16, 517–526.

Arsuffi, T. L., and Suberkropp, K. (1986). Growth of two stream cad-disflies (Trichoptera) on leaves colonized by different fungal species.Journal of the North American Benthological Society 5, 297–305.doi:10.2307/1467482

Bastian, M., Boyero, L., Jackes, B. R., and Pearson, R. G. (2007).Leaf litter diversity and shredder preferences in an Australian trop-ical rain-forest stream. Journal of Tropical Ecology 23, 219–229.doi:10.1017/S0266467406003920

Boyero, L., and Pearson, R. G. (2006). Intraspecific interference in a tropicalstream shredder guild. Marine and Freshwater Research 57, 201–206.doi:10.1071/MF05052

Canhoto, C., and Graça, M. A. S. (1995). Food value of introduced eucalyptleaves for a Mediterranean stream detritivore: Tipula lateralis. Fresh-water Biology 34, 209–214. doi:10.1111/J.1365-2427.1995.TB00881.X

Clapcott, J. E., and Bunn, S. E. (2003). Can C4 plants contribute to aquaticfood webs of subtropical streams? Freshwater Biology 48, 1105–1116.doi:10.1046/J.1365-2427.2003.01077.X

Coley, P. D., and Aide, T. M. (1991). Comparison of herbivory and plantdefenses in temperate and tropical broad-leaved forests. In ‘Plant–Animal Interactions: Evolutionary Ecology in Tropical and TemperateRegions’. (Eds P. W. Price, T. M. Lewinsohn, G. W. Fernandes andW. W. Benson.) pp. 25–49. (John Wiley and Sons: New York.)

Coley, P. D., and Barone, J. A. (1996). Herbivory and plant defenses intropical forests.Annual Review of Ecology and Systematics 27, 305–335.doi:10.1146/ANNUREV.ECOLSYS.27.1.305

Cuffney, T. F., Wallace, J. B., and Lugthart, G. J. (1990). Experimentalevidence quantifying the role of benthic invertebrates in organic mat-ter dynamics of headwater streams. Freshwater Biology 23, 281–299.doi:10.1111/J.1365-2427.1990.TB00272.X

Cummins, K. W. (1973). Trophic relations of aquatic insects. Annual Reviewof Entomology 18, 183–206. doi:10.1146/ANNUREV.EN.18.010173.001151

Cummins, K. W., and Klug, M. J. (1979). Feeding ecology of streaminvertebrates. Annual Review of Ecology and Systematics 10, 147–172.doi:10.1146/ANNUREV.ES.10.110179.001051

Dudgeon, D. (1999). The population dynamics of three species of Calam-oceratidae (Trichoptera) in a tropical forest stream. In ‘Proceedings ofthe 9th International Symposium on Trichoptera’. (Eds H. Malicky andP. Chantaramongkol.) pp. 83–91. (Faculty of Science, University ofChiang Mai: Thailand.)

Dudgeon, D. (2000). The ecology of tropical Asian rivers and streams inrelation to biodiversity conservation. Annual Review of Ecology andSystematics 31, 239–263. doi:10.1146/ANNUREV.ECOLSYS.31.1.239

Dudgeon, D., and Wu, K. K. Y. (1999). Leaf litter in a tropical stream:food or substrate for macroinvertebrates? Archiv fuer Hydrobiologie146, 65–82.

Feminella, J. W., and Resh, V. H. (1990). Hydrologic influences, disturbance,and intraspecific competition in a stream caddisfly population. Ecology71, 2083–2094. doi:10.2307/1938622

Friberg, N., and Jacobsen, D. (1999). Variation in growth of the detritivore-shredder Sericostoma personatum (Trichoptera). Freshwater Biology 42,625–635. doi:10.1046/J.1365-2427.1999.00501.X

Graça, M. A. S. (2001). The role of invertebrates on leaf litter decom-position in streams – a review. International Review of Hydrobiol-ogy 86, 383–393. doi:10.1002/1522-2632(200107)86:4/5<383::AID-IROH383>3.0.CO;2-D

Graça, M. A. S., Cressa, C., Gessner, M. O., Feio, M. J., Callies, K. A.,and Barrios, C. (2001). Food quality, feeding preferences, survival andgrowth of shredders from temperate and tropical streams. FreshwaterBiology 46, 947–957. doi:10.1046/J.1365-2427.2001.00729.X

Hieber, M., and Gessner, M. O. (2002). Contribution of stream detriti-vores, fungi, and bacteria to leaf breakdown based on biomass estimates.Ecology 83, 1026–1038.

Honek, A. (1993). Intraspecific variation in body size and fecundity ininsects: a general relationship. Oikos 66, 483–492. doi:10.2307/3544943

Irons, J. G., Oswood, M. W., and Bryant, J. P. (1988). Consumption of leafdetritus by a stream shredder: influence of tree species and nutrient status.Hydrobiologia 160, 53–61.

Irons, J. G., Oswood, M.W., Stout, R. J., and Pringle, C. M. (1994). Latitudinalpatterns in leaf litter breakdown: is temperature really important? Fresh-water Biology 32, 401–411. doi:10.1111/J.1365-2427.1994.TB01135.X

Iversen, T. M. (1974). Ingestion and growth in Sericostoma personatum(Trichoptera) in relation to the nitrogen content of ingested leaves. Oikos25, 278–282. doi:10.2307/3543945

Feeding by a tropical stream shredder Marine and Freshwater Research 901

Jacobsen, D., and Friberg, N. (1995). Food preference of the trichopteranlarvaAnabolia nervosa from two streams with different food availability.Hydrobiologia 308, 139–144.

Jacobsen, D., Cressa, C., Mathooko, J. M., and Dudgeon, D. (2008). Macro-invertebrates: composition, life histories and production. In ‘TropicalStream Ecology’. (Ed. D. Dudgeon.) pp. 65–105. (Academic Press:Burlington, MA.)

Li, A. O. Y., and Dudgeon, D. (2008). Food resources of shredders andother benthic macroinvertebrates in relation to shading conditionsin tropical Hong Kong streams. Freshwater Biology 53, 2011–2053.doi:10.1111/J.1365-2427.2008.02022.X

Li, A. O. Y., Ng, L. C. Y., and Dudgeon, D. (2008). Effects of leaf toughnessand nitrogen content on litter breakdown and macroinvertebrates in atropical stream. Aquatic Sciences, in press. doi:10.1007/S00027-008-8117-Y

Mathuriau, C., and Chauvet, E. (2002). Breakdown of leaf litter in a Neotrop-ical stream. Journal of the North American Benthological Society 21,384–396. doi:10.2307/1468477

Motomori, K., Mitsuhashi, H., and Nakano, S. (2001). Influence of leaflitter quality on the colonization and consumption of stream inverte-brate shredders. Ecological Research 16, 173–182. doi:10.1046/J.1440-1703.2001.00384.X

Nolen, J. A., and Pearson, R. G. (1993). Factors affecting litter process-ing by Anisocentropus kirramus (Trichoptera: Calamoceratidae) from anAustralian tropical rainforest stream. Freshwater Biology 29, 469–479.doi:10.1111/J.1365-2427.1993.TB00781.X

http://www.publish.csiro.au/journals/mfr

Parkyn, S. M., and Winterbourn, M. J. (1997). Leaf breakdown and coloni-sation by invertebrates in a headwater stream: comparisons of native andintroduced tree species. New Zealand Journal of Marine and FreshwaterResearch 31, 301–312.

Pearson, R. G., and Tobin, R. K. (1989). Litter consumption by invertebratesfrom an Australian tropical rainforest stream. Archiv fuer Hydrobiologie116, 71–80.

Pearson, R. G., Tobin, R. K., Smith, R. E. W., and Benson, L. J. (1989).Standing crop and processing of rainforest litter in a tropical Australianstream. Archiv fuer Hydrobiologie 115, 481–498.

Quinn, J. M., Smith, B. J., Burrell, G. P., and Parkyn, S. M. (2000). Leaf littercharacteristics affect colonisation by stream invertebrates and growth ofOlinga feredayi (Trichoptera: Conoesucidae). New Zealand Journal ofMarine and Freshwater Research 34, 273–287.

Rincón, J., and Martínez, F. (2006). Food quality and feeding prefer-ences of Phylloicus sp. (Trichoptera: Calamoceratidae). Journal of theNorth American Benthological Society 25, 209–215. doi:10.1899/0887-3593(2006)25[209:FQAFPO]2.0.CO;2

Stout, R. J. (1989). Effects of condensed tannins on leaf processing in mid-latitude and tropical streams: a theoretical approach. Canadian Journalof Fisheries and Aquatic Sciences 46, 1097–1106. doi:10.1139/F89-142

Manuscript received 13 April 2008, accepted 27 July 2008