Glucocorticoid hormone levels increase in the blood stream in response to a large range of social and physical stressors, affecting variables associated to fitness, such as reproductive output and immunocompetence. Although quantification of plasma levels of glucocorticoids has been used as an indicator of environmental stress in different clades of vertebrates, the existence of interspecific differences in magnitude of stress response, their functional bases and ecological correlates remain poorly investigated. In the present study, we tested the following hypotheses: (1) phyllogenetically close species of Bufonids differ in innate immunocompetence, baseline activity of the hypothalamic-pituitary-interrenal (HPI) axis, and response of the HPI axis to stressors; and (2) species showing higher baseline activity of the HPI axis are characterized by lower innate immunocompetence. To test these hypotheses, we compared plasma bactericidal ability against Escherichia coli, baseline field levels of corticosterone (CORT) during reproductive season, and levels of CORT under stressful conditions (captive maintenance plus physical restraint) of three species of toads from the genus Rhinella from Botucatu (SP/Brazil): R. icterica, R. schneiden, and R. ornata. We found interspecific variation in bactericidal ability and CORT levels, with R. ornata showing higher baseline and post-stress CORT levels, and R. schneiden showing higher plasma bactericidal ability. Bactericidal ability and baseline CORT levels are inversely related among species, suggesting that lower innate immunocompetence might be associated to immunosupressive effects of elevated CORT levels. Possible associations between these results and interspecific differences in reproductive behavior and sensitivity to environmental changes are discussed.

Published accounts and descriptions of Rhinella ceratophrys Boulenger, 1882 were all based on juvenile specimens until 1994, thus it had generally been presumed to be a diminutive species. Based on examination of additional material, including adult specimens, as well as the holotype, we here report on variation in this large-sized bufonid toad and provide a new diagnosis for the species. Additionally, we present notes on the ecology and distribution of this species.

The holotype of Drymobius heathii Cope (now Mastigodryas heathii) has remained unrecognized since the species was described in 1876. A review of specimens and associated data in the Academy of Natural Sciences of Philadelphia shows that one specimen, ANSP 11544, is very likely the holotype of this species. The presumptive holotype is redescribed and the coloration in life and natural history and other data for this species from northern Peru are presented. Mastigodryas heathii occurs in lowland coastal desert scrub and dry deciduous forests of the Pacific slope and interandean valleys. Its diet includes frogs, lizards, and rodents.

To establish the presence of amphibian and reptile species by cover and their diet in agroecosystems in the Colombian coffee belt, we sampled four farms in the Departamento del Quindío and two in the Departamento del Valle del Cauca (Colombia) from 2006 to 2008. Specimens were captured using both the VES technique and manual capture; each gastrointestinal sample was analyzed to get the type of diet (carnivore, omnivore or herbivore) and the frequency of consumed items (detritus, animal parts, plant material and minerals). Both the sensitivity index (IS) and the dominance index were calculated to find out whether each species belongs to open areas or forest, and to determine niche breadth. Differences between stomach and intestine were analyzed by using a Chi-square test. We captured 376 individuals of 19 species (nine frogs, three lizards, six snakes and one turtle) in crops, pastures, forests and forest of Guadua angustifolia. Centrolenid frogs were found mainly in forests and Guadua, and Rhinella marina, Leptodactylus colombiensis, Lithobates catesbeianus, two species of snakes and a turtle, in open areas. Gastrointestinal contents showed that most of the species are carnivorous. This paper is the first report of the diet of these species in Colombia especially in agroecosystems, being important to compare differences due to habitat transformation.

Arboreal snakes have evolved for a life in the aboveground vegetation where they are faced with the challenge of movement through an unstable substratum. Many species have ridged bodies that allow them to bridge gaps in the forest, saving them from descending to the ground and back up another plant. I tested the cantilevering ability of five species of Panamanian snakes in the laboratory and made additional observations in the wild. Even among the most highly specialized arboreal snakes there are differences in mean and maximum cantilevering distance.

Very little is known on the ecological attributes of Neotropical salamanders. The aim of this study was to evaluate the effect of two abiotic factors on the temporal and spatial abundance of B. paraensis. Data were collected during four periods, in 23 plots of 250 m² distributed randomly in Gunma Ecological Park, in the Brazilian state of Para. In each plot, temperature and relative humidity of the air were measured during searches, and abundance of salamanders was determined by active nocturnal searches. The abundance of salamanders varied significantly during the course of the year. The highest abundance (0–18) was recorded in the mid wet season, followed by the late wet season (0–7), early dry season (0–9), and late dry season (0–6). Spatial abundance of salamanders was influenced by climatic conditions only in the late dry season. Temporal and spatial variation in the abundance of the salamanders is associated with relative humidity, which was highest in the mid wet season, and lowest in the late dry season, affecting their activity and consequently their detectability during the searches.

Among the numerous and varied reproductive modes observed in anurans, some of the most uncommon are found in hemiphractids. For example, the hemiphractid genus Stefania is one of the rare anuran taxa in which females brood their eggs openly upon their backs with the embryos undergoing direct development. Much remains to be learned about reproductive patterns in Stefania and other hemiphractids. Here, using museum specimens, literature records, and specimens recently collected by us, we present data on clutch size variation and the relationship between clutch size and female snout-vent length throughout Stefania. We found a statistically significant correlation between clutch size and female snout-vent length for Stefania (46 individuals, 8 of 19 species) and for three of the four species examined individually (S. evansi, S. ginesi, and S. satelles). Only one species, S. ayangannae, showed no correlation between these traits although this result may be due to low sampling rather than the correlation being absent.

Amphibians play an important role in the energy flux between aquatic and terrestrial environments, exerting a “topdown” control on leaf-litter invertebrates in many forested environments. In the present study, we investigated activity patterns and diet composition of Odontophrynus carvalhoi in a tropical rainforest within a semi-arid area in northeastern Brazil. There was a positive correlation between the number of recorded individuals and the amount of rainfall on the day of observations, and three and seven days prior to the observations. Coleoptera, Opiliones, Gastropoda, and Diplopoda were, numerically, the most important prey categories, while Coleoptera, Orthoptera, and Gastropoda were the most important volumetrically. According to the index of relative importance (IRI), Coleoptera, Gastropoda, and Opiliones were the most important prey. Our data suggest that O. carvalhoi has a generalist diet and is mainly active in the leaf-litter during the nocturnal period.