The flower-visiting behaviour of bumble bees: floral complexity and learning

Abstract

Videotape records of flower-visiting behaviour of bumble bees (Bombus spp.) without previous foraging experience were compared with records of experienced foragers on flowers of six plant species representing a range of morphological complexity. Although the behaviour of experienced bees was relatively consistent, those without previous experience made many types of "errors" on their first flower visits. These included landing on inappropriate areas of flowers, assuming incorrect positions, and probing into areas of flowers other than in the vicinity of the nectary. The proportion of inexperienced foragers achieving a success criterion, defined as three sequential "errorless" visits, differed significantly among plant species. The time spent in trial and error learning before the criterion was obtained was significantly greater for flowers of high structural complexity than for those of intermediate and low complexity.The initial probing response of inexperienced bumble bees is mainly instinctive behaviour. However, exploitation of flowers also involves a learning component during which initial responses are modified according to the location of rewards in flowers of different plant species.f