Diet and microhabitat use by two Hylodinae species (Anura, Cycloramphidae) living in sympatry and syntopy in a Brazilian Atlantic Rainforest area

Maurício Almeida-Gomes, Fábio H. Hatano, Monique Van Sluys and Carlos F. D. Rocha

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Abstract: We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

NATURAL HISTORY TRAITS OF CROSSODACTYLUS AENEUS (ANURA, LEPTODACTYLIDAE, HYLODINAE) FROM AN ATLANTIC RAINFOREST AREA IN RIO DE JANEIRO STATE, SOUTHEASTERN BRAZIL

Tássia Jordão-Nogueira, Davor Vrcibradic, Jorge A. L. Pontes, Monique Van Sluys and Carlos F. D. Rocha.

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Abstract: There is currently little information on the biology of anurans of the genus Crossodactylus (Leptodactylidae, Hylodinae), which comprise small diurnal frogs that live associated with streams in areas of Atlantic Rainforest. In this study, we analyzed some aspects of the natural history of Crossodactylus aeneus in an area of Atlantic forest in the state of Rio de Janeiro, southeastern Brazil. A total of 37 individuals of C. aeneus were collected during the study, all of them associated with streams inside the forest. Most of the individuals (60%) were found on rocks. Most of the animals were collected during the day, although some were active at night. The diet of C. aeneus was composed of various arthropods, with beetles, ants, dipterans and insect larvae being the predominant items. Of the 21 collected females, eleven contained 70-127 unpigmented vitelogenic eggs.

Microhabitat use and feeding habits of Crossodactylus bokermanni Caramaschi and Sazima, 1985 (Anura, Hylodidae) at a site in southeastern Brazil

Milena Wachlevski, Paulo H. C. Souza, Katia Kopp and Paula C. Eterovick

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Abstract: We studied a population of Crossodactylus bokermanni in a stream at the Reserva Particular do Patrimônio Natural, Santuário do Caraça, south-eastern Brazil, with respect to microhabitat use and diet. We characterized microhabitats based on substrate, distance to water and exposure level of the occupying  individual (exposed or sheltered), and adjacent aquatic microhabitats (evaluated as potential nesting sites based on observed nests), according to water current (absent, slow or fast), substrate and depth. Calling males, silent males, ovigerous females, nonovigerous females and juveniles showed spatial niche overlap higher than that

expected by chance, with calling males showing the strongest preference for microhabitats close to potential nesting sites (with intermediate depths, fast current and sandy bottom). Only 14 males out of 48 individuals examined for stomach contents had prey in their stomachs. The food items with the highest electivity values were Coleoptera and Diptera, but preys with both high and low mobility were exploited.

Feeding habits of six anuran (Amphibia: Anura) species in a rainforest fragment in Northeastern Brazil

Ednilza M. Santos, Argus V. Almeida and Simão D. Vasconcelos.

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Abstract: Although Brazil encompasses one of the most abundant anuran faunas in the world, quantitative information on anuran ecology and diet are limited, especially in the Northeastern region. We analyzed the diet of six species: Hyla albomarginata, Hyla cf. branneri, Hyla minuta, Phyllomedusa aff. hypochondrialis (Hylidae), Leptodactylus natalensis, and Physalaemus cuvieri (Leptodactylidae) in a temporary pond in a rainforest remnant in Pernambuco, between 1999-2000. We analyzed diet composition, degree of food preference, and seasonal variations in diet. Leptodactylus natalensis and P. cuvieri showed higher diet diversity, whereas H. minuta consumed fewer food items. Insecta, Arachnida, and plants were preferential items for most species. Acari were consumed by all species; Hymenoptera, Odonata, and Coleoptera were also often consumed. A slight increase in diet diversity occurred in the rainy season. The species showed a generalist feeding behaviour, although P. cuvieri consumed Formicidae as major prey item.