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

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.

STOMACH MORPHOLOGY AND FIRST RECORD OF THE FRESHWATER SHRIMP Macrobrachium potiuna PREYING ON JUVENILE TREEFROG IN THE ATLANTIC FOREST

“…Freshwater shrimps are crucial for maintaining the trophic structure of lotic environments as they have an omnivorous diet that promotes nutrient cycling and energy flow in headwater streams (Carvalho et al 2011, Cruz et al 2021. They feed on organic plant debris in suspension or in the substratum (Carvalho et al 2011, Jimoh et al 2011, Lima et al 2014, as well as on insects, oligochaetes, microcrustaceans, mollusks, and small fish (Mirzajani et al 2020).…”