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In general, anurans tend to be nocturnal, though diurnal activity is characteristic of some groups. Studies show that frog activity may be inferred based on the number of individuals collected at different periods of the day, during large-scale field surveys. We investigated the best period of the day to conduct amphibian sampling in nine Atlantic Rainforest areas in southeastern Brazil, based on intensive field surveys. At each locality we employed similar sampling effort during diurnal, crepuscular and nocturnal searches (totaling 704.5 sampling hours). We pooled data from all localities for each period and estimated the proportion of frogs of each species active at each period based on the total number of individuals and on the number of species found during all surveys for that period. We recorded a total of 817 individual frogs from 69 species. Species richness was highest at night (median = 12 species), intermediate at dusk (median = 8), and lowest during the day (median = 4). The percentage of the total number of individual frogs found (pooled species) was highest during the night (ca. 53%) and lowest during the day (ca. 14%). Analyzing each species separately, the number of individuals recorded was consistently higher at dusk and night for most species. Our study evidences a trend for nocturnal activity for most Atlantic Rainforest frogs, with few species having primarily diurnal habits. Those results may favor future studies and conservation efforts for amphibian species.

Haddadus binotatus is an endemic anuran of the Brazilian Atlantic Forest and currently, there is no information about the diet of this species. We analyzed the diet of two populations of this anuran in two states in southeast Brazil. Samplings were carried out in 2004 in the state of Rio de Janeiro and in 2009 and 2010 in the state of Espírito Santo. Haddadus binotatus presented a rich diet composition, preying 19 prey types. Orthoptera, Coleoptera, and Blattodea were the most important preys in the Rio de Janeiro population, and Orthoptera, Araneae and Hemiptera were the most important in the Espírito Santo population. The diet composition differed numerically between the two localities, but not in terms of volume, which can reflect local differences in the prey availability in the two habitats. The jaw width limited the size of prey, which is expected for predators who swallow the preys without chewing. The proportion of individuals with empty stomachs was higher in the Rio de Janeiro population (39.2%) than in the Espírito Santo population (17.9%), suggesting that the former could be in a lower energy balance. The females of the species were larger than the males, which may result from the production of larger eggs.

We studied the leaf-litter frog community of Estação Ecológica Estadual Paraíso, in Guapimirim, Rio de Janeiro State, southeastern Brazil. Herein we combined three sampling methods (large plots, visual encounter surveys and pit-fall traps) to present data on species composition, richness, relative abundance and densities. The local assemblage of frogs associated to the leaf-litter was composed by 14 species, belonging to nine families. Haddadus binotatus, a direct-developing frog, was the most abundant species in the community. The estimated density of the local leaf-litter frog assemblage based on plot sampling was 4.3 frogs/100 m(2). Haddadus binotatus had the highest density (1.1 ind/100 m(2)). Frogs were predominantly found at night. Thoropa miliaris had the largest values of SVL (39.0 ± 10.3 mm), whereas the smallest species were Euparkerella brasiliensis (16.7 ± 2.2 mm) and E. cochranae (16.0 ± 2.7 mm). Rhinella ornata had the highest mean body mass (12.1 ± 7.5 g), and E. cochranae the lowest (0.4 ± 0.2 g). The overall frog mass was 938.6 g/ha. Our data support that higher densities of leaf-litter frogs tend to occur in the Neotropical region compared to the OldWorld tropics, tending to be higher in Central America than in South America.