An investigation of alkaloid sequestration by the poison frog Dendrobates auratus when fed the fire ant Solenopsis invicta

Abstract

Poison frogs are known for their bright coloration, parental care, and defensive toxins. Over 850 different alkaloids have been discovered in the skin of poison frogs. The alkaloid defenses are acquired from a specialized diet consisting primarily of ants and mites. The process by which those alkaloids are acquired is still primarily unknown. In this study we fed living Solenopsis invicta to the poison frog Dendrobates auratus in order to find new information about sequestration of alkaloid defenses. Our study also verified that populations of S. invicta found in North Carolina reflect GC-MS alkaloid profiles of 2,6 piperidines reported from other parts of the Americas. Dendrobates auratus ate S. invicta but there was no sequestration of any alkaloids. A novel method for administering alkaloid-containing arthropods in powder form was used to confirm the outcome of the live ant feeding study. These results have led to the formulation of a new “alkaloid specificity hypothesis” to explain variation in alkaloid selection between poison frog populations using a sequestration mechanism that is reliant on length of alkaloid side chains.