The Effect of Feeder Location on Pollen Collection by Bumble Bees in a Tomato Greenhouse in Ontario, Canada

The foraging behavior of bumble bees (Bombus impatiens Cresson) was examined as a function of feeder location containing sugar solution in a commercial tomato greenhouse in Manotick, Ontario, Canada. The feeders were located within the nest-box (fed-close) or placed 1.5 m away (fed-far) and the placement of the two types of colonies was counterbalanced over time. No effect of feeder location was found in colony activity levels or in pollen load size. A foraging trade-off between sugar solution and pollen collection, however, was found: the proportion of foraging trips in which pollen was brought back was significantly reduced for fed-far colonies, which contrasts with our laboratory study in which the opposite effect was found. We interpret our findings as possibly reflecting a limitation in pollen supply in the greenhouse: an already possibly strained ability to find and bring back pollen to the colony was accentuated by increasing the task demands of collecting sugar solution.