Vol. 51 No. 4, 2012

Feeding Ecology of Crossodactylus schmidti (Anura: Hylodidae) in Southern Brazil

Vinícius Matheus Caldart^1,*, Samanta Iop¹, Tiago Roberto Nunes Bertaso², and Sonia Zanini Cechin¹

¹Programa de Pós Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Univ. Federal de Santa Maria, Av. Roraima s/ n°, Camobi, CEP 97105-900, Santa Maria, Rio Grande do Sul, Brazil
²Graduação em Ciências Biológicas, Univ. Regional Integrada do Alto Uruguai e das Missões, Santo Ângelo, Rio Grande do Sul, Brazil

Vinícius Matheus Caldart, Samanta Iop, Tiago Roberto Nunes Bertaso, and Sonia Zanini Cechin (2012) The diet of the frog Crossodactylus schmidti was studied from Sept. 2009 to Mar. 2010 in the Turvo State Park, a locality of mesophytic semideciduous forest in southern Brazil, based on 93 stomach contents obtained by stomach-flushing (n = 80) and analysis of preserved specimens (n = 13). In addition to describing the diet, we determined the niche breadth on the basis of prey categories, and calculated electivities to evaluate the relation between the diet and prey availability in the environment. We also tested for differences in diets between sexes and between adults and juveniles. Crossodactylus schmidti consumed 19 categories of prey, of which ants, beetles, and dipterans had the highest importance values. Despite the varied diet, the niche breadth was narrow, with only a few prey categories being consumed predominantly. Ants, dipterans, and spiders were consumed in proportions similar to those estimated in the environment. There was no relationship between mouth width and length/volume of prey consumed, but there were significant sexual and age differences in the diet composition. Males consumed 18 prey categories, and females consumed 15; juveniles consumed 13 prey categories, and adults consumed 19. Despite differences in diet compositions between the sex and age groups, ants were the most important prey for all of them. Considering the varied diet and relationships between some of the most important items in the diet with their availability in the environment, C. schmidti can be characterized as an opportunistic feeder with feeding habits similar to those of other Crossodactylus species. Similarities in the importance of prey items such as ants, beetles, dipterans, and insect larvae in the diet of C. schmidti and other Hylodidae species are discussed.

Key words: Crossodactylus schmidti, Hylodidae, Diet, Niche breadth, Prey availability.

*Correspondence: E-mail:viniciuscaldart@yahoo.com.br