Diet and trophic groups of an aquatic insect community in a tropical stream

R L Motta,V S Uieda

doi:10.1590/s1519-69842004000500010

Abstract

The diet and trophic groups of an assemblage of aquatic insects were studied in a tropical stream. Genera of the orders Ephemeroptera, Odonata, Plecoptera, Lepidoptera, and Hemiptera showed feeding specialization. Others, such as Trichoptera, Coleoptera, and Diptera, showed great diet variation with genera of different trophic groups. Seasonal variation of insect diet, evident only for some genera of the orders Trichoptera, Lepidoptera, Coleoptera, and Diptera, was due to the differences observed in community composition and to generalist habits of these genera. However, the seasonal comparison of trophic groups showed no significant statistical differences. The great importance of organic matter, a non-limited resource, in the diet of Ribeirão do Atalho aquatic insects may be the explanation for the trophic stability in this community organization.

Highlights

Aquatic invertebrates predominate in the trophic structure of streams (Wallace et al, 1987) and their feeding habits can influence all aspects of their life (Yule, 1996)
The major resource categories exploited by aquatic insects were organic matter, aquatic animals, and organic matter associated with algae (Fig. 1)
Based upon feeding mode and ingested detritus particle size (Cummins, 1973; Merritt & Cummins, 1996), aquatic insects were grouped into six categories: collectors, shredders, scrapers, and predators

Summary

Introduction

Aquatic invertebrates predominate in the trophic structure of streams (Wallace et al, 1987) and their feeding habits can influence all aspects (life cycle, habitat choice, and behavior) of their life (Yule, 1996). Aquatic insects are fundamental in understanding trophic structure in streams (Cummins, 1973). The trophic ecology of aquatic insects and their functional role in the environment are widely studied in the Northern Hemisphere. The great importance of insects in the trophic structure of streams in contrast with the scanty data available in the literature about their feeding habits indicates the need of studies on this subject. The purpose of this work was to investigate the diet and trophic groups of aquatic insects in a tropical stream

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Results

Conclusion