Polimorfismo explicado por especialização da dieta de Astyanax bimaculatus (Actinopterygii: Characidae) em hábitats de riachos

Abstract

The response of organisms to environmental heterogeneity and its relation to the coexistence of similar species and / or individuals of the same specie can be evidenced by their trophic ecology and morphology. In this study, we aimed to quantify the polymorphism of a specie in in Jaguaribe river (Ceará, Brazil) and, we concluded through trophic and functional analyzes, that the distribution pattern of Astyanax bimaculatus functional traits, in streams habitats, was mainly directed by diet specialization. Our results point to diet as the main predictor of the functional pattern - even in the damming presence, which are considered high magnitude disturbances capable of interfering with fish morphology - and should therefore be considered in habitat selection studies for fish species; and that individuals from different habitats can be considered as unique ecological entities within a population. Thus, we argue that to develop a better understanding of the magnitude of intraspecific variation in relation to interspecific and its biological and ecological determinants; and assess their impact on ecosystem functioning, species characterizations based on individuals from different habitat types should be considered.