EAGER: Poison Frogs and Toxic Arthropods – Diversification and parallel evolution of frog predators with their alkaloid-bearing prey

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Poison frogs have venomous substances in their skins, but they do not produce these chemicals on their own. Instead, they harvest these venoms from their arthropod diet: ants and mites. More than 800 different chemicals were found in these frogs. However, the diversity of ants and mites is so vast that understanding how poison frogs gain toxins from their arthropod food remains a mystery. This project will examine the connection between frog predators and toxic arthropods, which are valued more by the toxins they contain than by their nutritional value. This project will examine the diversity, genetics and evolution of toxic arthropods and their poison frog predators. The relevance of this project resides on the discovery of new knowledge that can then be shared with the community to advance our understanding of megadiverse regions like the South American rain forest. This basic research will provide insights into how the recycling of toxins occurs in natural ecosystems. The research team (St. John’s University, European and Latin-American partners) will provide learning experiences to underrepresented groups in STEM with workshops for students and open lectures for the public in NYC and beyond. SJU is an institution in the heart of the most ethnographically diverse county in the US with a large concentration of minority students. This work will involve training these scholars in tropical ecology, genomics and bioinformatics.Chemical defenses in poison frogs have a well-documented dietary origin. Yet little is known about the functional, phylogenomic biodiversity and ecological processes that connect the toxic arthropod base with their poison frog consumers. The movement of such defenses in trophic chains requires an intricate ecosystem of connections among interacting species. To answer this question, this project examines a model system centered on a section of the trophic chain that includes poison frogs and their alkaloid-bearing arthropod diet. The project addresses two major evolutionary and ecological dimensions: (1) phylogenomic and alkaloid diversities across poison frogs and their dietary ants and mites and (2) transcriptomics, physiological adaptations and evolutionary parallelisms evidenced by differential gene expression among the origins of alkaloid sequestration in poison frogs and their toxic arthropod diet. These goals will address how parallelisms, coevolution/codiversification and convergence evolved in poison frogs and their toxic arthropod under the context of bioaccumulation, differential gene expression and gene diversification. Such comparisons will contribute to a new level of understanding of the cycling of defensive toxins across biodiverse Neotropical communities. The proposed research will use predator-prey dynamics involving chemical defenses in some of the most threatened ecosystems, the Chocoan and Amazonian tropical forests, where biodiversity is being lost daily.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.