Natural diet of Macrobrachium brasiliense (Crustacea, Decapoda) in a Cerrado stream

Barbara R F Da Cruz,Alessandra A De P Bueno,Marina C Cunha,Giuliano B Jacobucci

doi:10.1590/1678-4766e2021003

Barbara R F Da Cruz, Alessandra A De P Bueno + Show 2 more

Open Access

https://doi.org/10.1590/1678-4766e2021003

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Abstract

ABSTRACT Knowledge about the diet of a given species is essential to provide information on the growth and maintenance of populations in a natural environment. Macrobrachium brasiliense (Heller, 1862) is a species of freshwater prawn widely distributed in Brazil, being frequent in aquatic environments inserted in the Cerrado biome. The aim of this study was to evaluate the natural diet of a population of M. brasiliense, comparing the consumed food items according to sex, seasonality and body size of individuals. Monthly collections were carried out between September 2018 and August 2019. The individuals collected had their sex identified and the length of the cephalothorax measured. Stomach content was assessed based on the degree of repletion, the method of points and the frequency of occurrence. There was a high frequency of plant material in the stomach contents and a smaller but significant frequency of aquatic insects. There were no significant differences regarding the diet of males and females and between the dry and rainy seasons. It was observed an increase in total insect consumption with the increase in size of males and females of M. brasiliense. A diet preference for Trichoptera was recorded in both sampling periods for males and females. The results obtained confirm an omnivorous diet for the species and suggest that the composition and proportion of items may vary depending on the size of the individuals and the availability of the items in the environment.

Highlights

A total of 219 individuals of M. brasiliense were analyzed, 68 males, with cephalothorax length (CL) ranging from 3.1 mm to 8.0 mm and 151 females, with CL ranging from 3.1 mm and 9.3 mm
The surface water temperature and turbidity variability were not enough to result in differences in food availability of the main animal itens and probably of the plant material to cause diet changes between dry and rainy seasons
The proportion of empty stomachs recorded in studies of natural diet of other species of Macrobrachium is considerably variable ranging from 2.87% to 99% of the stomachs analyzed (Albertoni et al, 2003; Sethi et al, 2013; Lima et al, 2014; Lavajoo et al, 2019)

Summary

Introduction

Freshwater prawns play an important trophic role in the aquatic ecosystems in which they occur, because in addition to being important consumers, they serve as a food resource for reptiles (Borteiro et al, 2009), fishes (Haluch et al, 2009) and humans (Odinetz-Collart & Moreira, 1993; BondBuckup et al, 2009). These crustaceans are considered key species in the functioning of aquatic ecosystems, as they can influence the structuring of benthic communities, as well as in ecological processes such as leaf debris degradation (Menge et al, 1994). Such variation is due to the type of environment in which these animals occur and the availability of food resources (Lavajoo et al, 2019)

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