This study focused on life strategies of species from functional feeding groups (FFGs) found in a tropical stream of the Sirumalai hills, South India. We examined the life cycle and secondary production of species of shredders (Lepidostoma nuburagangai), scrapers (Baetis sp.), collectors (Choroterpes alagarensis), and predators (Neoperla biseriata). In addition, we studied the assemblage structure of functional feeding groups. We found the collectors occupied the highest percentage, followed in turn by scrapers, predators, and shredders. The diversity of FFGs was higher at riffle areas and assemblage with stream substrates differing in each functional group. An asynchronous life cycle was observed for Baetis, C. alagarensis, and N. biseriata, while L. nuburagangai was found in four to five generations per year. We acquired data on secondary production of scraper species of Baetis, which reached the highest values among all investigated species. This observation stresses the importance of scrapers as playing a key role in converting coarse particulate organic matter to fine particulate organic matter with low or high abundances of shredder population and maintaining the food chain in tropical streams. 1. Introduction Tropical forests cover 15–20% of the earth’s land surface and about half of this is being converted to agricultural land and for other human purposes. More than 50% of the world’s biodiversity is found in the tropical forests. Freshwater ecosystems are relatively more important than the terrestrial ecosystems because aquatic organisms are highly susceptible to climatic variation and anthropogenic impact [1]. The allochthonous organic substrate provides protection and habitat space and it has fundamental importance as a food source for aquatic macroinvertebrates [2]. Aquatic macroinvertebrates are classified into four major functional feeding groups (FFGs) based on the morphobehavioural mechanisms of food acquisition rather than taxonomic groups as follows: shredders, scrapers, collectors, and predators [3]. Feeding measures that contribute to fluvial trophic dynamics encompass FFGs and provide information on the balance of feeding strategies (food acquisition and morphology) in the benthic assemblage [4]. The major food sources utilized by macroinvertebrates are the epilithic layer that grows on the surfaces of substrates (consumed by scrapers), the coarse detritus of leaves falling from riparian vegetation (consumed by shredders), the fine detritus either deposited on the substrate or suspended in the water column (consumed by
References
[1]
O. E. Sala, F. S. Chapin III, J. J. Armesto et al., “Global biodiversity scenarios for the year 2100,” Science, vol. 287, no. 5459, pp. 1770–1774, 2000.
[2]
E. F. Benfield, “Comparison of litterfall input to streams,” Journal of the North American Benthological Society, vol. 16, no. 1, pp. 104–108, 1997.
[3]
R. W. Merritt, K. W. Cummins, M. B. Berg et al., “Development and application of a macroinvertebrate functional-group approach in the bioassessment of remnant river oxbows in southwest Florida,” Journal of the North American Benthological Society, vol. 21, no. 2, pp. 290–310, 2002.
[4]
R. E. Uwadiae, “Macroinvertebrates functional feeding groups as indices of biological assessment in a tropical aquatic ecosystem: implications for ecosystem functions,” New York Science Journal, vol. 3, no. 8, pp. 6–15, 2010.
[5]
D. Dudgeon, Tropical Asian Streams: Zoobenthos, Ecology and Conservation, Hong Kong University Press, Pokfulam Road, Hong Kong, 1999.
[6]
R. L. Vannote, G. W. Minshall, K. W. Cummins, J. R. Sedell, and C. E. Cushing, “The river continuum concept,” Canadian Journal of Fisheries and Aquatic Sciences, vol. 37, no. 1, pp. 130–137, 1980.
[7]
A. Bij de Vaate and T. I. Pavluk, “Practicability of the Index of Trophic Completeness for running waters,” Hydrobiologia, vol. 519, no. 1–3, pp. 49–60, 2004.
[8]
S. Tomanova, E. Goitia, and J. Hele？ic, “Trophic levels and functional feeding groups of macroinvertebrates in neotropical streams,” Hydrobiologia, vol. 556, no. 1, pp. 251–264, 2006.
[9]
S. Blanchet, G. Loot, and J. J. Dodson, “Competition, predation and flow rate as mediators of direct and indirect effects in a stream food chain,” Oecologia, vol. 157, no. 1, pp. 93–104, 2008.
[10]
V. V. Gertseva, J. E. Schindler, V. I. Gertsev, N. Y. Ponomarev, and W. R. English, “A simulation model of the dynamics of aquatic macroinvertebrate communities,” Ecological Modelling, vol. 176, no. 1-2, pp. 173–186, 2004.
[11]
S. Dinakaran and S. Anbalagan, “Habitat aptness and spatial heterogeneity of aquatic insects in Western Ghats: linking multivariate analysis,” The Ecoscan, vol. 2, no. 1, pp. 51–60, 2008.
[12]
S. Anbalagan, J. Pandiarajan, S. Dinakaran, and M. Krishnan, “Effect of tourism on the distribution of larval blackflies (Diptera: Simulium) in Palni hills of South India,” Acta Hydrobiologica Sinica, vol. 35, no. 4, pp. 688–692, 2011.
[13]
S. Anbalagan, S. Dinakaran, and M. Krishnan, “Spatio-temporal dynamics of leaf litter associated macroinvertebrates in streams of peninsular India,” Ecologia, vol. 2, no. 1, pp. 1–11, 2012.
[14]
S. Dinakaran and S. Anbalagan, “Anthropogenic impacts on aquatic insects in six streams of south Western Ghats,” Journal of Insect Science, vol. 7, article 37, 2007.
[15]
APHA, Standard Methods for the Examination of Water and Wastewater, American Public Health Association, Washington, DC, USA, 16th edition, 1995.
[16]
A. C. Benke, A. D. Huryn, L. A. Smock, and J. B. Wallace, “Length-mass relationships for freshwater macroinvertebrates in North America with particular reference to the southeastern United States,” Journal of the North American Benthological Society, vol. 18, no. 3, pp. 308–343, 1999.
[17]
A. C. Benke, “Secondary production of aquatic insects,” in The Ecology of Aquatic Insects, V. H. Resh and D. M. Rosenberg, Eds., pp. 289–322, Praeger Publishers, New York, NY, USA, 1984.
[18]
S. Dinakaran, S. Anbalagan, and C. Balachandran, “A new species of Caddisfly (Trichoptera: Lepidostomatidae: Lepidostoma) from Tamil Nadu, India,” Journal of Threatened Taxa, vol. 5, no. 1, pp. 3531–3535, 2013.
[19]
S. Dinakaran, C. Balachadran, and S. Anbalagan, “A new species of Choroterpes (Ephemeroptera: Leptophlebiidae) from a tropical stream of south India,” Zootaxa, no. 2064, pp. 21–26, 2009.
[20]
P. Zwick, S. Anbalagan, and S. Dinakaran, “Neoperla biseriata sp. n., a new stonefly from Tamil Nadu, India (Plecoptera: Perlidae),” Aquatic Insects, vol. 29, no. 4, pp. 241–245, 2007.
[21]
L. G. Oliveira, Aspects da biologia de communidades de insetos aquaticos da ordem Trichoptera Kirby, 1813, em corregos de cerrado do municipio de Pirenopolis, Estado de Goias [Tese de Doutorado], Universidade de Sao Paulo, Sao Paulo, Brazil, 1996.
[22]
R. M. Kikuchi and V. S. Uieda, “Composicao da comunidae de invertebrados de um ambiente lotico tropical e sua variacao especial e temporal,” in Ecologia de Insetos Aquaticos, J. L. Nessimian and A. L. Carvalho, Eds., vol. 5 of Series Oecologia Brasiliensis, pp. 157–174, PPGE-UFRJ, Rio de Janeiro, Brazil, 1998.
[23]
M. R. Vinson and C. P. Hawkins, “Biodiversity of stream insects: variation at local, basin, and regional scales,” Annual Review of Entomology, vol. 43, pp. 271–293, 1998.
[24]
S. Anbalagan and S. Dinakaran, “Seasonal variation of diversity and habitat preferences of aquatic insects along the longitudinal gradient of the Gadana River Basin, South-West Ghats (India),” Acta Zoologica Bulgarica, vol. 58, no. 2, pp. 253–264, 2006.
[25]
N. H. Anderson and E. Grafius, “Utilization and processing of allochthonous material by stream Trichoptera,” Verhandlungen der Internationalen Vereinigung für Theoretische und Angewandte Limnologie, vol. 19, pp. 3083–3088, 1975.
[26]
J. R. Webster and E. F. Benfield, “Vascular plant breakdown in freshwater ecosystems.,” Annual review of ecology and systematics. Vol. 17, pp. 567–594, 1986.
[27]
L. J. Benson and R. G. Pearson, “Litter inputs to a tropical Australian rainforest stream,” Australian Journal of Ecology, vol. 18, no. 4, pp. 377–383, 1993.
[28]
C. M. Yule, M. Y. Leong, K. C. Liew et al., “Shredders in Malaysia: abundance and richness are higher in cool upland tropical streams,” Journal of the North American Benthological Society, vol. 28, no. 2, pp. 404–415, 2009.
[29]
A. D. Huryn and J. B. Wallace, “Life history and production of stream insects,” Annual Review of Entomology, vol. 45, pp. 83–110, 2000.
[30]
G. R. Bright, “Secondary benthic production in tropical Island stream,” Limnology and Oceanography, vol. 27, no. 3, pp. 472–480, 1982.
[31]
R. A. Jenkins, K. R. Wade, and E. Pugh, “Macroinvertebrate-habitat relationships in the River Teifi catchment and the significance to conservation.,” Freshwater Biology, vol. 14, no. 1, pp. 23–42, 1984.
[32]
T. Fujitani, “Species composition and distribution patterns of baetid nymphs (Baetidae: Ephemeroptera) in a Japanese stream,” Hydrobiologia, vol. 485, pp. 111–121, 2002.
[33]
M. Salas and D. Dudgeon, “Life histories, production dynamics and resource utilisation of mayflies (Ephemeroptera) in two tropical Asian forest streams,” Freshwater Biology, vol. 48, no. 3, pp. 485–499, 2003.
[34]
R. Marchant, “Estimates of annual production for some aquatic insects from the La Trobe River, Victoria.,” Australian Journal of Marine & Freshwater Research, vol. 37, no. 2, pp. 113–120, 1986.
[35]
A. Ramírez and C. M. Pringle, “Structure and production of a benthic insect assemblage in a neotropical stream,” Journal of the North American Benthological Society, vol. 17, no. 4, pp. 443–463, 1998.
[36]
B. W. Sweeney and R. L. Vannote, “Size variation and the distribution of hemimetabolous aquatic insects: two thermal equilibrium hypotheses,” Science, vol. 200, no. 4340, pp. 444–446, 1978.
[37]
R. L. Vannote and B. W. Sweeney, “Geographic analysis of thermal equilibriums, conceptual model for evaluating the effect of natural and modified thermal regimes on aquatic insect communities,” The American Nature, vol. 115, pp. 667–695, 1980.
[38]
A. K. Rasmussen, Species diversity and ecology of Trichoptera (Caddisflies) and Plecoptera (Stoneflies) in Ravine ecosystems of Northern Florida [Ph.D. thesis], University of Florida, 2004.
[39]
S. A. Grubbs and K. W. Cummins, “Linkages between riparian forest composition and shredder voltinism,” Archiv für Hydrobiologie, vol. 137, no. 1, pp. 39–58, 1996.
[40]
W. L. Hilsenhoff, J. L. Longridge, R. P. Narf, K. J. Tennessen, and C. P. Walton, Aquatic Insects of the Pine-Popple River, Wisconsin, Technical Bulletin no. 54, Wisconsin Department of Natural Resources, Madison, Wis, USA, 1972.
[41]
D. J. Giberson and H. L. Garnett, “Species composition, distribution, and summer emergence phenology of stoneflies (Insecta: Plecoptera) from Catamaran Brook, New Brunswick,” Canadian Journal of Zoology, vol. 74, no. 7, pp. 1260–1267, 1996.
[42]
S. Anbalagan, T. Pratheep, S. Dinakaran, and M. Krishnan, “Effects of two leaf litter species on the colonization of macroinvertebrates in a tropical stream of India,” The Bioscan, vol. 7, no. 3, pp. 533–538, 2012.
