Effects of Colonization, Geography and Environment on Genetic Divergence in the Intermediate Leaf-Nosed Bat, Hipposideros larvatus

SIMPLE SUMMARY: It is vitally important to unravel the evolutionary processes and potential drivers of genetic differentiation among populations in evolutionary biology. However, it remains unexplored how those drivers act on the genetic divergence among bat populations. In this study, we studied the genetic structure and evolutionary history of a bat species, Hipposideros larvatus from mainland China and Hainan Island. Using microsatellites and mtDNA to analyze genetic differentiation, we found an obvious genetic structure between the mainland and the island in H. larvatus. Integrating the genetic data, geography and climatic factors, we uncovered the combined effects including geography, environment and colonization history, on the genetic variation in H. larvatus. Our results are valuable in understanding the complex evolutionary processes among bat populations and provide implications for the conservation of island bat populations. ABSTRACT: Determining the evolutionary history and population drivers, such as past large-scale climatic oscillations, stochastic processes and ecological adaptations, represents one of the aims of evolutionary biology. Hipposideros larvatus is a common bat species in Southern China, including Hainan Island. We examined genetic variation in H. larvatus using mitochondrial DNA and nuclear microsatellites. We found a population structure on both markers with a geographic pattern that corresponds well with the structure on mainland China and Hainan Island. To understand the contributions of geography, the environment and colonization history to the observed population structure, we tested isolation by distance (IBD), isolation by adaptation (IBA) and isolation by colonization (IBC) using serial Mantel tests and RDA analysis. The results showed significant impacts of IBD, IBA and IBC on neutral genetic variation, suggesting that genetic variation in H. larvatus is greatly affected by neutral processes, environmental adaptation and colonization history. This study enriches our understanding of the complex evolutionary forces that shape the distribution of genetic variation in bats.