Predation by the Grapsid Crab, Armasesangustum (smith, 1870), on Tadpolesof the Green Poison Frog,

On Taboga Island, Republic of Panama, a grapsid crab, Armases angustum (Smith, 1870), was found in one of the treeholes of a buttress tree that was used heavily by Dendrobates auratus Girard, 1855 for breeding. The crab ate tadpoles in captivity and thus is a new potential predator of D. auratus. D. auratus is a species of terrestrial frog with parental care. After a lengthy courtship, females deposit up to 6 eggs under a leaf where the male fertilizes them. When the tadpoles emerge, the male transports them on his back, usually one at a time, either to small ephemeral pools, such as those in fallen leaves and fruit husks, or to larger, more permanent pools, such as those in treeholes. Both environments pose risks for tadpoles. Small pools frequently dry up before tadpoles complete metamorphosis and permanent water sources may be easily exploited by predators as a predictable source of prey. Although adult D. auratus have potent skin toxins (Myers & Daly, 1983), these toxins are diet derived, so the palatable tadpoles are vulnerable to predators (Daly et al. 1994a, b). The use of ephemeral pools and difŽ cult to observe treeholes means that the complete range of dendrobatid tadpole predators is unknown.As the nontoxic stages are the most vulnerable to predation, the main sources of dendrobatid mortality may be overlooked. The most studied cause of mortality to D. auratus tadpoles is cannibalism (Summers, 1990; Caldwell & De Araújo, 1998).D. auratus tadpoles not only consume each other, but also any other tadpole or larval invertebrates living in the same waterpool (Summers, 1990; Caldwell & De Araújo, 1998). On Taboga, a large pool which held water even during dry periods, was heavily used by D. auratus for tadpole deposition. This treehole was near the base of a tree