抄録
Between May and July 2007, eight queens of Bombus terrestris, which has been introduced as an agricultural pollinator and naturalized over a large area of Hokkaido, Northern Japan, were observed or captured in the Notsuke Peninsula. This area is the most important range of a rare native species, B. florilegus. In early June, we spent 20 hours investigating flower visits by introduced and native bumblebees in the Notsuke Peninsula. A total of 217 queens from seven native species were observed, including six B. florilegus and one B. terrestris queen. Despite the lack of detailed information, B. florilegus, which belongs to the same subgenus Bombus, may have similar ecological characteristics to B. terrestris; such characteristics may include flower use and nesting habitat selection. Therefore, B. terrestris has the potential to negatively affect B. florilegus and is likely to displace it through competition. In addition, these two species have similar hair color patterns, with two yellow bands on the thorax and a white tail. Therefore, the introduced bees should be carefully suppressed in this area.
