Bees, Flowers and Polarization.

Abstract

Event Abstract Back to Event Bees, Flowers and Polarization. James Foster1*, Camilla R. Sharkey1, Heather M. Whitney1, Nicholas W. Roberts1 and Julian C. Partridge1 1 University of Bristol, School of Biological Sciences, United Kingdom The flowers of angiosperm plants use uni-modal and multi-modal signals to attract pollinators (1-3). The modalities of such signals are wide-ranging, from reflected ultraviolet light (4) or iridescence (5), to microscopic differences in petal texture (6). The benefit of adding extra information to a signal, particularly from another modality, is an increase in the accuracy of decision-making (7). Pollinating insects can also perceive the polarization of light, and whilst work has demonstrated that this sensory ability is used for terrestrial navigation (8-11) and water detection (12-13), little has been done to investigate whether insect polarization vision plays a role in signal detection. In this study, we investigate the ability of a bumblebee species, Bombus terrestris, to discriminate between rewarding and aversive artificial flowers that differed by a contrast in the angle of polarization and when viewed across the ultraviolet-visible range. Bees were able to learn the rewarding flowers using these polarization signals, with foraging experience leading to greater proportion of rewarding flowers being chosen. Furthermore, this capacity relies on the viewing direction; polarization patterns were only learned for downwards facing flowers and not for upwards facing ones. This agrees with how polarization sensitivity in bees is restricted to the upwards-looking region of the eye, -the dorsal rim area (DRA) (14). These results are presented alongside images of polarization patterns in downwards facing flowers, revealing that polarized information exists in the natural environment. Investigation of such newly discovered components of natural flowers, and how they operate in multi-modal signal-receiver relationship may lead to broader comprehension of the interactions between bumblebees and bumblebee-pollinated plants, species that are of significant economic importance. Figure 1 Acknowledgements The authors would like to thank Jelena Ruscic, Ria Woodfield and Will Amos for their invaluable help in conducting these experiments.