Population Genetics of the Asian Parti-Colored Bat, Vespertilio sinensis: Insights into Seasonal Migration in the Japanese Archipelago

Understanding bat movement patterns is essential for epidemiology and bat conservation. However, such information is lacking in East Asia, including the Japanese archipelago. It is also unclear whether the straits surrounding the Japanese archipelago affect bat movement. We conducted a population genetic analysis for the Asian parti-colored bat (<i>Vespertilio sinensis</i>), distributed in Far East Russia and East Asia, including Japan. Samples were collected from three colonies in Hokkaido and eight in Honshu and sequenced for a mtDNA Cytochrome-b region. The population structure of this species was examined using phylogenetic and molecular variance analyses, which revealed a genetic separation between Hokkaido and Honshu; this suggested that the Tsugaru Strait, located between Hokkaido and Honshu, is a geographic barrier. Our demographic analysis revealed that <i>V. sinensis</i> of Hokkaido and Honshu had different population expansion histories. The genetic divergence between Hokkaido and Honshu further suggests that two-way migration across the Tsugaru Strait did not occur with <i>V. sinensis</i>. However, in the Mantel test, which was restricted to the Honshu population, the response to isolation by distance differed in summer and winter. This seasonal difference in response may indicate higher fidelity to summer roost or habitat compared to wintering areas. When combined with the results of a previous banding study, which showed that females exhibited two-way movement and males exhibited one-way movement, our findings support the conclusion that <i>V. sinensis</i> is migratory. These results provide new insights into the movement patterns of bat species within the Japanese archipelago.