Poor alkaloid sequestration by arrow poison frogs of the genus Phyllobates from Costa Rica

Frogs of the genus Phyllobates from Colombia are known to contain the highly toxic alkaloid batrachotoxin, but species from Central America exhibit only very low levels or are entirely free of this toxin. In the present study alcohol extracts from 101 specimens of Phyllobates lugubris and Phyllobates vittatus and 21 of three sympatric species (Dendrobates pumilio, Dendrobates auratus, Dendrobates granuliferus) from Costa Rica were analyzed by gas chromatography-mass spectrometry. Whereas the extracts of the Dendrobates species exhibited typical profiles of toxic alkaloids, those of the two Phyllobates species contained low levels of few alkaloids only, batrachotoxin was not detected. Although the feeding pattern of the Dendrobates and Phyllobates species are similar as revealed by examination of their stomach content (mainly ants and mites), the Phyllobates species are poorly sequestering alkaloids from their food source in contrast to the Dendrobates frogs.