Honeybees choose "incorrect" colors that are similar to target flowers in preference to novel colors

Abstract

How non-rewarding flowers are able to receive sufficient pollinator visits to enable successful reproduction is an intriguing question. This study investigates the psychophysics of honeybee perception when individual honeybees are presented with a choice of a known non-rewarding color that is perceptually similar to a previously rewarding (but not present) target color, or a novel color. In experiment one, bees were tested for color preferences to three different artificial blue flowers, two of which were very similar in color; there was no color preference for any of the stimuli. In a second experiment, bees were provided with absolute conditioning to one of the perceptually similar stimuli. In subsequent non-rewarded tests these bees could not discriminate between the similar colors but could discriminate the non-similar color. In a third experiment, bees provided with differential conditioning (target rewarded and distractor unrewarded) learned to reliably discriminate between the perceptually similar stimuli. Surprisingly, when these bees were presented with a task of choosing between the known non-rewarding flower and a novel flower, bees chose the non-rewarding flower. The finding reveals that there is a strong perceptual effect on bees to choose stimuli that are perceptually similar to known rewarding flowers. The results explain how non-rewarding floral mimics may gain sufficient pollinator visits to enable pollination.