This study evaluated the seasonality in the diet of Moenkhausia dichroura (Kner, 1858) and M. sanctaefilomenae (Steindachner, 1907), sympatric species of the Cancela stream, state of Mato Grosso, Brazil. Regardless of the seasonal period, allochthonous food source predominated in the diet of both species (>50% of all items consumed) and among these terrestrial insects were the dominant resource. However, aquatic insects were important in the diet of M. dichroura as well. Hymenoptera (Formicidae) was the dominant item to both species, thus they were characterized as terrestrial insectivorous. The restricted diet of these species is confirmed by the trophic niche breadth, whose values were in general low: Ba=0.26 to M. dichroura in both periods and Ba=0.41 and 0.38 in the dry and rainy period, respectively, to M. sanctaefilomenae. The feeding overlap was high in the rainy period (Ojk=0.75) and intermediate in the dry period (Ojk=0.41), showing that the food partitioning between species was larger in this period.
Diet; Moenkhausia dichroura; M. sanctaefilomenae; coexistence
