A species of bumblebee imported to Hokkaido as a pollinator for greenhouse vegetables is rapidly expanding its presence in the wild and threatens to disturb the prefecture's native ecosystem.

Buff-tailed bumblebees, which are 1 to 2 cm and characterized by their white-tipped abdomens, have settled only in Hokkaido so far as the climate is similar to that of the species' native Europe.

Experts say the infestation could threaten not only to eliminate native bees but also hamper pollination as it sometimes opens a hole in petals and collects nectar without touching the pistils or stamens and thus doesn't transport the pollen.