Learning constraints and floral choice behaviour in bumble bees

Abstract. Insects foraging on flowers tend to restrict their visits to a single species of plant while bypassing other equally rewarding species. This behaviour may result from perceptual limitations, the demands of energetic efficiency, or both. Perceptual limitations may be the product of underlying constraints on the processing of information by pollinators. Foraging simultaneously on several species can lower foraging efficiency through reduced ability to recognize the preferred species among others. This hypothesis was tested in laboratory experiments with bumble bees. Bumble bees learned to discriminate between one non-rewarding floral type and either one, two or three rewarding floral types that differed only in colour. Bees' learning rates were higher in experimental sessions with fewer numbers of rewarding floral types. The results suggest that when bees forage on an increasing number of floral types, their ability to discriminate between these and non-rewarding types is reduced considerably.