Orientation to polarized light in tethered flying honeybees

Abstract

ABSTRACTBehavioral responses of honeybees to a zenithal polarized light stimulus were observed using a tethered animal in a flight simulator. Flight direction of the bee was recorded by monitoring the horizontal movement of its abdomen, which was strongly anti-correlated with its torque. When the e-vector orientation of the polarized light was rotated clockwise or counterclockwise, the bee responded with periodic right-and-left abdominal movements; however, the bee did not show any clear periodic movement under the static e-vector or depolarized stimulus. The steering frequency of the bee was well coordinated with the e-vector rotation frequency of the stimulus, indicating that the flying bee oriented itself to a certain e-vector orientation, i.e., exhibited polarotaxis. The percentage of bees exhibiting clear polarotaxis was much smaller under the fast stimulus (3.6 ° s-1) compared with that of the slow stimulus (0.9 or 1.8 ° s-1). The bee did not demonstrate any polarotactic behavior after the dorsal rim region of its eyes, which mediates insect polarization vision in general, was bilaterally covered with black paint. The bees demonstrated a high preference for e-vector orientations between 120 to 180°. Each bee exhibited similar e-vector preferences under clockwise and counterclockwise stimuli, indicating that each bee has its own e-vector preference, which probably depends on the bee’s previous foraging experience. Our results strongly suggest that the flying honeybees utilize the e-vector information from the skylight to deduce their heading orientation for navigation.Summary statementTethered flying bees exhibited polarotaxis under a zenithal rotating e-vector stimulus, in which their right-and-left abdominal movements were coincident with the rotation of the stimulus.