Robbing of Field Bean Flowers by the Short-Tongued Bumble BeeBombus TerrestrisL.

SummaryMost flowers produced during early flowering of autumn-sown field beans had small holes in the base of the corolla which indicated that they had been robbed by Bombus terrestris. The proportion of robbed flowers decreased as flowering continued. Slightly fewer flowers of spring-sown plants were robbed. There was no evidence of damage to the reproductive structures of 100 robbed flowers of the cultivar Maris Bead. Of the flowers sampled from the third, fourth and fifth flowering nodes of field bean plants growing near shelter at the paddock margin, 62% were robbed. Of the pods which subsequently formed at these nodes 59% were from flowers which had been robbed. This suggests that robbing of the flower by short-tongued bumble bees did not prejudice either pollination by other insects or pod development.