Dieta de Moenkhausia bonita (Characiformes: characidae) em riachos da bacia do Rio Formoso

Abstract

Morphological, behavioral, ontogenetic and seasonal characteristics can be determining factors for the diet of small species in streams. Aim: To characterize the diet composition of Moenkhausia bonita (Characiformes: Characidae) and its temporal and ontogenetic variations in streams in the Formoso River basin. Methods: The samples were collected in seven streams on two occasions along the year (dry and rainy seasons). The food items were analyzed according to the volumetric and occurrence frequency methods and the diet was characterized through the Food Index (IAi%). To determine ontogeny, the specimens were divided into five size classes in the dry (S1 to S5) and rainy (C1 to C5) seasons. To verify the difference between the species’ diet between the size classes and the seasons of the year, the Permutational Multivariate Analysis of Variance – PERMANOVA analysis was performed. Results: Moenkhausia bonita was classified as an invertivore when it consumed basically both aquatic and terrestrial inverte brates (99.5% of the diet), with a higher consumption of aquatic invertebrates. There was a significant difference in the diet of M. bonita between the dry and rainy seasons, and although the species basically consumed the same items in the two studied seasons, the proportions were different and there was no difference in the diet between size classes and between the season vs size class interactions. Conclusions: We concluded that M. bonita diet is based on autochthonous resources regardless of the size class, but that there were different consumption patterns when comparing the different seasons of the year. The present study provided information on the feeding of M. bonita and on its diet spectrum in different size classes and seasons of the year, enabling a better understanding of the species, the importance of invertebrates in its diet and the need for future studies on the biology, ecology and behavior of this species.