Spatiotemporal Aspects of Alkaloid Distribution in Dendrobates auratus and Microsympatric Arthropods from Oahu, Hawaii
Poison frogs represent an interesting case of acquired toxicity and selection. The majority of alkaloids found in the skins of these frogs are of dietary origin, arising from arthropod forage, most commonly ants and mites. We have examined three collections of D. auratus, a species introduced to Oahu, HI in the 1930 s. Collections from Oahu and Panama indicate spatial and temporal changes as well as microsympatric individual variation in frogs, correlated with arthropods in leaf litter. Pumiliotoxins (PTXs) and decahydroquinoline (DHQ) dimers were observed along with hydroxylated metabolites, which this species is known to produce. Hydroxylated PTXs were observed in frogs but not arthropod forage, supporting frogs as the unique producer of these metabolites. Unsaturated precursors of DHQ dimers were also observed, lending credence to the proposed Diels-Alder pathway for their formation.