Origins of chemical defense in poison frogs

Over the last 50 million years, poison frogs (family Dendrobatidae) have evolved to sequester alkaloids from diminutive arthropod prey three independent times. Along with origins of chemical defense, these dendrobatids have undergone extensive changes in metabolism, skin morphology, diet, coloration, behavior, and neurophysiology. Thus, poison frogs present an excellent system for identifying mechanisms underlying the origins and diversification of complex novel phenotypes.

Why don't poison frogs poison themselves? Their chemical defenses target a variety of ion channel proteins in nervous systems that govern action potentials and neurotransmitter release. Any organism susceptible to these chemicals would not survive being covered in them. We study evolutionary changes in nervous system proteins and other physiological systems that are targeted by poison frog chemical defenses.

Currently funded by NIH NIGMS R35GM150574

Previously funded by NSF (GRFP, DBI-1556967, DUE-0942345, CHE-1531972, IOS-1556982), National Geographic Society (Young Explorer Grant #9468-14), Society of Systematic Biologists, North Carolina Herpetological Society, Society for the Study of Reptiles and Amphibians, Chicago Herpetological Society, Texas Herpetological Society

PUBLICATIONS

Tarvin et al. 2024. Passive accumulation of alkaloids in putatively non-toxic frogs challenges paradigms of the origins of acquired chemical defenses. bioRxiv DOI: 10.1101/2024.05.13.593697

Tarvin et al. 2017. Interacting amino acid replacements allow poison frogs to evolve epibatidine resistance. Science 357: 1261–1266. PDF • https://doi.org/10.1126/science.aan5061

Tarvin et al. 2016. Convergent substitutions in sodium channel suggest multiple origins of toxin resistance in poison frogs. Molecular Biology and Evolution 33:1068-1081. PDF • https://doi.org/10.1093/molbev/msv350

Santos et al. 2016. A review of chemical defense in poison frogs (Dendrobatidae): Ecology, pharmacokinetics and autoresistance. In: Schulte, BA, TE Goodwin, MH Ferkin, editors. Chemical Signals in Vertebrates 13. Switzerland: Springer International Publishing. p. 305-337. PDF • link