ABSTRACT
Many insects exploit the partial plane polarization of skylight for visual compass orientation and/or navigation. In the present study, using a tethering system, we investigated how flying bees respond to polarized light stimuli. The behavioral responses of honeybees (Apis mellifera) 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 deg s−1) compared with that under a slow stimulus (0.9 or 1.8 deg s−1). Bees did not demonstrate any polarotactic behavior after the dorsal rim area of the eyes, which mediates insect polarization vision in general, was bilaterally covered with black paint. Preferred e-vector orientations under the clockwise stimulus varied among individuals and distributed throughout −90 to 90 deg. Some bees showed similar preferred e-vector orientations for clockwise and counterclockwise stimuli whereas others did not. Our results strongly suggest that flying honeybees utilize the e-vector information from the skylight to deduce their heading orientation for navigation.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: N.K., R.O., M.S.; Methodology: N.K., R.O., M.S.; Software: N.K., R.O.; Validation: N.K., R.O., M.S.; Formal analysis: N.K., R.O., M.S.; Investigation: N.K., R.O., M.S.; Data curation: R.O., M.S.; Writing - original draft: M.S.; Writing - review & editing: N.K., R.O., M.S.; Visualization: R.O., M.S.; Supervision: M.S.; Project administration: M.S.; Funding acquisition: R.O., M.S.
Funding
This work was supported by KAKENHI from the Japan Society for the Promotion of Science (15KT0106, 16K07439 and 17H05975 to M.S.; 16K07442 to R.O.) and a Bilateral Joint Research Project with the Australian Research Council from the Japan Society for the Promotion of Science (CH50427010 to M.S.).
Supplementary information
Supplementary information available online at https://jeb.biologists.org/lookup/doi/10.1242/jeb.228254.supplemental
- Received May 4, 2020.
- Accepted October 16, 2020.
- © 2020. Published by The Company of Biologists Ltd
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