Geographic variation of the diet of Melanophryniscus rubriventris (Anura: Bufonidae) in northwestern Argentina

BONANSEA, MARIA INES; VAIRA, MARCOS

JOURNAL OF HERPETOLOGY

Society for the Study of Amphibians and Reptiles

Lugar: Ohio; Año: 2007 vol. 41 p. 231 - 236

0022-1511

Increasing evidence shows that alkaloids in the skins of poisonous frogs are sequestered from a specialized diet of ants. It is considered likely that in the small aposematic bufonid genus Melanophryniscus, skin alkaloids are taken up via a similar system. However, quantitative aspects of the diet in this genus remain poorly studied. As a result, studies that correlate diet and skin alkaloids in these toads are precluded by the lack of extensive information on the diet of most species and populations within the genus. We describe diet composition of Melanophryniscus rubriventris with a particular focus on geographic variation over much of its range distribution in northwestern Argentina and compare the diet of this species with that of other members of the genus. The diet of M. rubriventris was composed of 17 arthropod prey categories. The species consumed primarily small, gregarious prey such as ants, mites, aphids, burrowing bugs, and beetles. Diet composition of the populations studied was similar in the number of prey categories, but we found noticeable interpopulation variation in the proportion of each prey itemconsumed. Earlier works had reported that ants, collembolans, and mites were prominent in the diet of other Melanophryniscus. Our study indicates that, although ants are common prey, they are not the main prey category in all populations.