Genetic evidence for female-biased dispersal in the bullfrog, Rana catesbeiana (Ranidae)

Sex-biased dispersal is an important but unexplored area of amphibian ecology. We predicted female-biased dispersal in the bullfrog (Rana catesbeiana) based on aspects of their mating system and tested this prediction using data from seven polymorphic DNA microsatellite loci. Allelic (F-statistics) and genotypic [assignment index, (AIc)] frequencies from nine Ontario populations support our prediction, although significant sex differences in inbreeding and variance of AIc were not detected. The diversity of mating systems found in amphibians represents an important avenue for investigating the relationship between reproductive systems, dispersal and phylogeny.