Molecular Analysis of Hybridization in Two North Florida Cricket Frogs, Acris creptians and Acris gryllus

Hybridization is the process in which evolutionarily distinct individuals come into contact with each other and interbreed. Hybridization can be evaluated using phenotypic traits from each species. Levels of gene transfer can also be utilized. Hybridization is a universal process and most commonly occurs between closely related species. Cricket frogs (genus: Acris) are an anuran species distributed throughout the southeastern U.S. This genus is split into three individual species, Acris crepitans, Acris gryllus, and Acris blanchardi. We aimed to test the levels of hybridization between A. gryllus and A. crepitans within the Big Bend region of northern Florida where the two species interact in sympatry. We sampled frogs from 10 different sites with 67 samples total. To assess hybridization, we extracted and sequenced DNA for thousands of loci and conducted several population generic and hybridization analyses. We hypothesized that there can be one of three possible outcomes: 1) there are strong species boundaries between Acris crepitans and Acris gryllus, 2) that there is unidirectional gene flow between Acris crepitans to Acris gryllus or vice versa, and that the other species has little to no gene flow, or 3) there is equal gene flow between the two species. Overall, we found little support for hybridization where the two species cooccur, suggesting strong reproductive boundaries between A. crepitans and A. gryllus.