Diet, sexual dimorphism, and fertility aspects of Melanophryniscus fulvoguttatus (Mertens, 1937) from Central-East Brazil

Melanophryniscus fulvoguttatus is a small toad that inhabits the Cerrado, Atlantic Forest, and humid Chaco of South America. Due to its aposematic coloration and behavior, it is a species that may present chemical defenses such as alkaloids and a restricted diet similar to other species of the genus. Although it was described in the early 20th century, there is still little information on its natural history and ecology. Here, we described the diet, tested the sexual dimorphism, and calculated the fertility index of M. fulvoguttatus based on a sample of eight males and 21 females from a population within the Cerrado. Sexual dimorphism was assessed using 15 morphometric measures; diet was calculated as an index of relative importance by prey item and tested for sex differences; fertility was tested for relations between body size and the number of eggs; and we also estimated the reproductive investment. Our results demonstrate that this population’s diet consisted mostly of ant species, with Pheidole radoszkowskii being the most important, followed by Crematogaster sp. and Cyphomyrmex transversus. Regarding sexual dimorphism, we observed that females were significantly larger than males, with a positive relationship between female size and the number of eggs. We did not find significant differences in the diets of males and females. Although the diet and reproductive aspects of M. fulvoguttatus are similar to those of its congeneric species, further studies are needed in order to address the relationship between the species diet and its chemical defenses.