Trophic structure of macroinvertebrates in tropical pasture streams

Bruna Neves Da Silveira-Manzotti,Angelo Rodrigo Manzotti,Lilian Casatti,Mônica Ceneviva-Bastos

doi:10.1590/s2179-975x0316

Bruna Neves Da Silveira-Manzotti, Angelo Rodrigo Manzotti + Show 2 more

Open Access

https://doi.org/10.1590/s2179-975x0316

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Abstract

Abstract: Aim The aim of this study was to describe the diet of stream macroinvertebrates and to determine their trophic groups. Methods Invertebrates were sampled with D nets in three pasture streams. They were identified to genus level and submitted to gut content analysis, except for fluid feeders such as hemipterans, to which diet data was obtained from the literature. Trophic groups were determined based on a similarity analysis using the Bray-Curtis similarity coefficient. Results Five trophic groups were defined: fine-detritivores (feed mostly on fine particulate organic matter - FPOM), coarse-detritivores/herbivores (feed mostly on coarse particulate organic matter - CPOM - and plant material), omnivores, specialist-predators (prey upon aquatic insects only), and generalist-predators. Ephemeroptera, Diptera (except Tanypodinae), Coleoptera, and Trichoptera (except Smicridea) were detritivores. The caddis Macronema (Trichoptera) fed exclusively on plant detritus and Tanypodinae and Smicridea were classified as omnivores. The odonate families Calopterygidae and Gomphidae were classified as specialist-predators, while Macrobrachium (Decapoda), Belostoma, and Limnocoris (Hemiptera) were generalist-predators. Conclusions The great quantity and frequency of occurrence of FPOM consumed by most taxa highlight the importance of this food resource for macroinvertebrate communities from tropical streams. Furthermore, observed variations on trophic group assignment for some taxa indicate the generalist and opportunistic nature of these aquatic invertebrates. Such findings reinforce the importance of conducting gut content analysis on macroinvertebrates to understand their role in the structure and functioning of tropical streams.

Highlights

IntroductionStreams ecosystems support a wide range of taxonomic groups, such as plants (moss, ferns, aquatic macrophytes), algae, fungi, bacteria, planktonic organisms, invertebrates (insects, mollusks, crustaceans), and vertebrates (fish, amphibians, reptiles, mammals) (Allan & Castilho, 2007)
Streams ecosystems support a wide range of taxonomic groups, such as plants, algae, fungi, bacteria, planktonic organisms, invertebrates, and vertebrates (Allan & Castilho, 2007)
Invertebrates were sampled with D nets in three pasture streams. They were identified to genus level and submitted to gut content analysis, except for fluid feeders such as hemipterans, to which diet data was obtained from the literature

Summary

Introduction

Streams ecosystems support a wide range of taxonomic groups, such as plants (moss, ferns, aquatic macrophytes), algae, fungi, bacteria, planktonic organisms, invertebrates (insects, mollusks, crustaceans), and vertebrates (fish, amphibians, reptiles, mammals) (Allan & Castilho, 2007). There is a growing need to study macroinvertebrate biology to better understand the functioning of stream ecosystems and to contribute to their management, directing conservation and mitigation measures (Moulton, 1998; Wright & Covich, 2005; Gonçalves Junior et al, 2006; Wantzen & Wagner, 2006). Such understanding is limited by practical problems that range from the difficulty to identify macroinvertebrate immature stages, even at genus level, to the scarcity of available morphological and behavioral data (Oliveira & Froehlich, 1997). The trophic approach can be used as a tool to access the ecological processes that underlie stream ecosystem structure and function (Gessner & Chauvet, 2002; Pascoal et al, 2005; Cummins et al, 2005)

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