Genetic structure of the bumble bee Bombus hypocrita sapporoensis, a potential domestic pollinator for crops in Japan

Abstract

The European bumble bee, Bombus terrestris, is an excellent commercial pollinator. In Japan, B. terrestris is categorized as an invasive alien species, and the use of the bee is restricted. In this study, we identify the native bumble bee Bombus hypocrita sapporoensis as a candidate commercial pollinator in Hokkaido Island. To evaluate the risk of disturbing the natural genetic structure if this bee is used as a commercial pollinator, we sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene to elucidate the phylogenetic relationship of B. h. sapporoensis in Hokkaido Island and the Asian continent. In addition, we analyzed six microsatellites to further investigate the population genetic structure in Hokkaido Island. The mitochondrial analyses revealed that there is little differentiation within Hokkaido Island; however, there is considerable differentiation between Hokkaido and the Asian continent. Microsatellite analyses using STRUCTURE showed that B. h. sapporoensis in Hokkaido was divided into two genetic groups. Individuals belonging to each group were distributed throughout Hokkaido Island, and no clear geographical differentiation was observed. These results indicate that there would be little risk of genetic disturbance if bees from Hokkaido Island were used. However, it would be advisable to avoid importing continental bees as a pollinating insect in Hokkaido Island.