REPLACEMENT OF BOMBUS-MUSCORUM BY BOMBUS-PASCUORUM IN NORTHERN BRITAIN

Records of bumble bees from four collecting trips (1977, 1978, 1988, a nd 1994) in northern Britain show apparent changes in the incidences o f two species. Until 1988, Bombus muscorum (Linnaeus) and Bombus pascu orum (Scopoli) were found in the counties of Cumbria, Durham, and Nort h Yorkshire. Only B. muscorum was found in the Orkney Islands in 1978. In 1994, however, B. pascuorum was found abundantly in all of these a reas, and in the Orkney Islands we could find only a single B. muscoru m. From these data, B. pascuorum appears to have been replacing B. mus corum in some parts of northern Britain.