Tokai University reveals new facts about Asian parti-colored bat ecology

A research group led by Graduate Student Shumpei Kamiyama (at the time of research) from the Graduate School of Biology and Professor Kuniko Kawai from the Department of Biology, School of Biological Sciences at Tokai University announced on June 26 that their DNA analyses have revealed the migration ecology of the Asian parti-colored bat, which is widely distributed throughout the Japanese archipelago. They found that seasonal migration across the Tsugaru Strait by groups does not occur. Their results were published in Zoological Science, issued by the Zoological Society of Japan on April 25.

The Asian parti-colored bat (Vespertilio sinensis) is widely distributed from the Japanese archipelago through East Asia to the Russian Far East. It is known that females alone form colonies from spring to the end of summer for reproduction and child-rearing, but these colonies disperse in autumn and the bats hibernate in winter. Based on wing morphology, they are believed to have long-distance flight capabilities, and banding surveys have suggested the possibility of seasonal migration similar to bird migration. While information on bat migration is important from epidemiological and conservation perspectives, research has been insufficient.

Therefore, in this study, the group analyzed the base sequences of the mitochondrial DNA cytochrome-b gene of 273 individual Asian parti-colored bats from 11 populations distributed from Hokkaido to Kyoto Prefecture to investigate population genetic structure. They further examined the possibility of seasonal migration by comparing summer and winter populations.

As a result, clear genetic differentiation was observed between Hokkaido populations and Honshu populations, suggesting that the Tsugaru Strait functions as a geographic barrier to seasonal migration between the two regions.

When examining the relationship between geographic distance and genetic distance limited to Honshu populations, they observed a tendency for genetic distance between populations to increase with geographic separation (isolation by distance) during summer, but this pattern was not seen in winter.

This indicates that while individuals from diverse regions (genetic populations) gather at wintering sites, there is a tendency to return to birthplaces during summer. These migration patterns support the movement patterns shown by previous banding surveys. It became clear that this species may engage in seasonal migration between wintering sites and birthplaces.

In the future, the group plans to conduct detailed analyses using more genetic information and work toward elucidating the comprehensive migration ecology of the Asian parti-colored bat.

Kawai commented: "It was surprising that the Tsugaru Strait acted as a migration barrier for the Asian parti-colored bat, which is believed capable of long-distance flight. We are currently conducting more detailed analyses of the genetic structure of this species' populations using nuclear genomes, while also advancing phylogeographic research with the addition of continental populations. We hope to eventually reveal the complete history of how this species came to inhabit and expand its distribution throughout the Japanese archipelago."

Journal Information
Publication: Zoological Science
Title: Population Genetics of the Asian Parti-Colored Bat, Vespertilio sinensis: Insights into Seasonal Migration in the Japanese Archipelago
DOI: 10.2108/zs230119