Resumo: Estudar hábitos alimentares é crucial para entender as complexas interações predador-presa. Embora os anuros tenham papel fundamental no controle das populações de artrópodes, a dieta de várias espécies neotropicais é pouco conhecida. Descrevemos a frequência e a ocorrência de presas e sua massa seca no conteúdo estomacal da rã Pristimantis paulodutrai, no nordeste do estado da Bahia, Brasil. Com base no conteúdo estomacal de 30 indivíduos, Araneae, Isopoda e Formicidae foram os itens alimentares mais importantes. A dieta generalista desta rã, a qual parece ser conservada filogeneticamente entre os Pristimantis, provavelmente está ligada à sua dominância ecológica nos habitats pesquisados. Nosso estudo corrobora a alta relevância trófica dos Robber Frogs em florestas tropicais como predadores generalistas.

Abstract: Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.

In anurans, acoustic communication is a major mechanism of pre-zygotic isolation, since it carries information about species recognition. Detailed descriptions of the acoustic properties of anuran advertisement calls provide important data to taxonomist and to the understanding of the evolution of the group. Herein we re-describe the advertisement call of the hylid frog Dendropsophus microps (Peters, 1872) after analyzing a larger sample than that of previous descriptions. We also compare the acoustic properties of the call in two populations and discuss the effect of the presence of the sister species, Dendropsophus giesleri (Mertens, 1950), a potential competitor, in one of the populations. Additionally, we provide information on calling sites and size of males. Males of D. microps emit two types of calls, which differ mainly in pulse repetition rate. Type "A" call has a mean frequency band varying from 4574 to 5452 Hz, (mean dominant frequency = 4972 Hz). Type "B" call has a mean frequency band varying from 4488 to 5417 Hz (mean dominant frequency = 4913 Hz). The calls of D. microps and D. giesleri are the only in the D. parviceps species group that have harmonic structure. The spectral properties of the call showed low intra-individual variation, being considered static, while the temporal properties were highly variable. Compared with males from the Boracéia population, males from the Ribeirão Grande population called from lower perches, and their calls had slightly lower frequency bands and significantly higher pulse rates in their type "B" calls. Inter-populational differences in acoustic properties, body size and use of calling sites could be related to selective forces associated with the presence of the sister species, a potential competitor for the population from Ribeirão Grande.