The ability to sequester the alkaloid epibatidine is widespread among dendrobatid poison frogs

Dendrobatid poison frogs sequester alkaloids from an arthropod diet and use them in chemical defense. Alkaloid defenses vary considerably within and among species, with important consequences for the protection they can and do provide against microorganisms and predators. Most of this variation is attributed to differences in frog diet and prey availability, but emerging evidence also suggests that frogs differ in their physiological ability to sequester alkaloids. Epibatidines are one of the most geographically and phylogenetically restricted alkaloid classes in poison frogs, having been found naturally only in two genera of dendrobatids ( Epipedobates and Ameerega ) from Ecuador and northern Peru. To test the hypothesis that the ability to sequester epibatidine is confined to the lineages Epipedobates and Ameerega , we experimentally administered epibatidine to individuals of five species, representing three different lineages of dendrobatid poison frogs, including those known to possess ( Epipedobates anthonyi ) and lack ( Ranitomeya variabilis , Ranitomeya imitator , Phyllobates vittatus , Dendrobates tinctorius ) epibatidines in nature. All five species sequestered epibatidine; however, the percentage sequestered varied significantly across species with Epipedobates and Ranitomeya accumulating about 2.4× more than Phyllobates or Dendrobates . Our results suggest that the absence of epibatidine in certain dendrobatids is not due to the inability of these frogs to sequester epibatidine, but may instead result from differences in prey availability and/or dietary preference. Our finding of differences in the percentage of epibatidine sequestered among species points to the importance that physiological differences in sequestration play in explaining some of the alkaloid variation (including epibatidine) observed among dendrobatid poison frogs.