Natural diet of the endemic freshwater crab Aegla castro Schmitt, 1942 (Decapoda: Anomura: Aeglidae)

Abstract

Abstract We characterized the natural diet and feeding dynamics of Aegla castroSchmitt, 1942 (Aeglidae), an endemic freshwater crab. Research was undertaken on the trophic spectrum of the species by analyzing the stomach contents of individuals collected in a stream in southeastern Brazil, and evaluating the diet through the index of relative importance (IRI). Seasonal and circadian variations in diet composition were analyzed, and the feeding dynamics investigated through repletion index (RI) analysis. We analyzed a total of 240 stomachs and identified 20 main food categories of the diet, which were studied throughout the seasons. Aegla castro maintained a constant RI throughout the year, with a peak of food activity between midnight (00) and 0600. The species was characterized as an omnivorous generalist and opportunist. The high overlay in the diet composition of adults of both sexes and juveniles indicates that they share the same food resources, even though they seem to exploit them in different quantities and frequencies. Future research should focus on the species of Aegla whose diets have not yet been described, and use available data to inform trophic network analyses and models.