The Pollinating Activities of Bumble Bees and Honeybees in Relation to Temperature, Competing Forage Plants, and Competition from Other Foragers

Abstract

Observations on three species of bees showed that, in both red clover and lucerne, there was a significant positive correlation between the temperature and the number of honeybees foraging. The number of B. terrestris foraging was not significantly affected by temperature (11–33°C); on lucerne, there was a highly significant correlation between numbers of honeybees and of B. terrestris, the one robbing nectar and the other collecting pollen. On red clover, pollen foraging by B. ruderatus decreased with increasing temperature, because of increased competition from honeybees. Results are discussed in relation to the pollinating effectiveness of the different groups of foraging bees.