The effects of size on the diets of six sympatric species of postmetamorphic litter anurans in central Amazonia

Abstract

All species of diurnal leaf-litter anurans in central Amazonian changed the type and size of their prey as they grew. Postmetamorphic individuals of all species ate principally mites and collembolans, and larger frogs ate larger prey of other types. The shift in prey types was not a passive effect of selection for larger prey. There was a strong relationship between electivity for prey types and frog size, independent of electivities for prey size, in six of the seven species. This study showed that most species in the community had strong ontogenetic changes in diet composition and electivity for prey types, and these changes did not conform to simple models of the effects of predator size and diet quality.