Convergence of gut microbiota in myrmecophagous amphibians

Abstract

The gut microbiome composition of terrestrial vertebrates is known to converge in response to common specialized dietary strategies, like leaf-eating(folivory) or ant- and termite-eating (myrmecophagy). To date, such convergence has been studied in mammals and birds, but has been neglected inamphibians. Here, we analysed 15 anuran species (frogs and toads) representing five Neotropical families and demonstrated the compositionalconvergence of the gut microbiomes of distantly related myrmecophagousspecies. Specifically, we found that the gut microbial communities of bufonids and microhylids, which have independently evolved myrmecophagy,were significantly more similar than expected based on their hosts’evolutionary divergence. Conversely, we found that gut microbiome composition was significantly associated with host evolutionary history in somecases. For instance, the microbiome composition of Xenohyla truncata, oneof the few known amphibians that eat fruits, was not different from thoseof closely related tree frogs with an arthropod generalist diet. Bacterialtaxa overrepresented in myrmecophagous species relative to other hostfamilies include Paludibacter, Treponema, and Rikenellaceae, suggestingdiet-mediated selection and prey-to-predator transmission likely drivingthe observed compositional convergence. This study provides a basis forexamining the roles of the gut microbiome in host tolerance and sequestrationof toxic alkaloids from ants and termites.