What the minute shield frogs Adelophryne eat at a humid forest relict in Ceará state, northeastern Brazil

In the present study, we describe the feeding habits of two threatened Adelophryne species for the first time. Additionally, for A. maranguapensis we tested whether predator body size influences the prey size consumed, and whether sexual dietary differences exist. This study was carried out, during the rainy season, in the rainforest enclave of Serra de Maranguape, Ceara state, northeastern Brazil. We found 19 prey categories, Acari and Formicidae being the most frequent and important prey items consumed by A. maranguapensis. Prey volume and frog snout-vent length were positively related, but we found no significant differences regarding the volume and composition of prey items consumed by males and females. For A. baturitensis, we found nine prey categories, with Formicidae and Isoptera as the most important prey items. Although both Adelophryne species have different microhabitat-use, these species had a high trophic niche overlap. Except for Formicidae and Coleoptera, all prey items groups found in the stomachs of both species are new for the diet of the genus. These frogs are considered cryptical species and more studies are still needed to understand which niche aspects allow them successfully to live in sympatry even though they have a high trophic niche overlap.