Prey availability in a forest fragment in Eastern Amazon: how is it related to the diet of anurans Leptodactylus fuscus and Physalaemus ephippifer?

Many studies focus on the diet of anurans and how species consume available food resources. However, few link these data with the resources available in the environment. This gap in information may lead to a partial understanding of the feeding strategies of this group. We evaluate the availability of food resources and analyze how two sympatric anurans, Physalaemus ephippifer and Leptodactylus fuscus, utilize available prey. The research was conducted on the edge of a forest fragment in northeastern Pará state, Brazil, over three years during the rainy season. Specimens of both species were collected, and their diets were evaluated by the frequency of occurrence (FOi) and the feeding importance (VFIi) of each prey category. We also analyzed the relationship between prey availability and the diet of each anuran species. We identified 20 prey categories in the stomachs of P. ephippifer, with Formicidae being the most frequent and important over the three years. In L. fuscus, 19 prey categories were found, with Orthoptera, Formicidae, and Coleoptera being the most significant. We recorded 24 invertebrate categories in the study area, with Collembola, Coleoptera, and Formicidae being the most abundant. Both anurans shared many prey categories but showed distinct preferences in their diet, indicating selective foraging behavior.