Abstract1. Mating and aggressive behaviour was observed in four species of dendrobatid frogs in Corcovado National Park, Costa Rica: Colostethus nubicola, Colostethus talamancae, Phyllobates vittatus and Dendrobates granuliferus. 2. Males of both species of Colostethus were more likely to respond to call playbacks than male P. vittatus or D. granuliferus. Male D. granuliferus were less likely to be found calling than males of the other species. Conspecific male-male aggression was observed in P. vittatus, but not in the other species. 3. Females were more active during courtship in P. vittatus. Female-female aggression was observed on one occasion in P. vittatus. Females were more likely to reject males than the reverse in all species. 4. These observations suggest that sexual conflict occurs in P. vittatus, but not in C. nubicola or C. talamancae.
