Bumblebees (Apidae

A survey of the insects visiting common buckwheat flowers and examination of the pollen attached to the insects captured at the field in Hokkaido was carried out in order to determine their role as pollinator. Two bumblebee species, Bombus ardens sakagamii and B. hypocrite sapporoensis, were captured as the predominant species (75.4%) and 97.6% of B. ardens sakagamii and 96.0% of B. hypocrite sapporoensis had tetraploid common buckwheat pollen attached to their body surface even though they were captured in a diploid common buckwheat field. From these results, these two bumblebee species were thought to be the main pollinators of common buckwheat in Hokkaido for the first time.