title: Bumblebees learn polarization patterns.
abstract: Foraging insect pollinators such as bees must find and identify flowers in a complex visual environment. Bees use skylight polarization patterns for navigation, a capacity mediated by the polarization-sensitive dorsal rim area (DRA) of their eye. While other insects use polarization sensitivity to identify appropriate habitats, oviposition sites, and food sources, to date no nonnavigational functions of polarization vision have been identified in bees. Here we investigated the ability of bumblebees (Bombus terrestris) to learn polarization patterns on artificial "flowers" in order to obtain a food reward. We show that foraging bumblebees can learn to discriminate between two differently polarized targets, but only when the target artificial "flower" is viewed from below. A context for these results is provided by polarization imaging of bee-pollinated flowers, revealing the potential for polarization patterns in real flowers. Bees may therefore have the ability to use polarization vision, possibly mediated by their polarization-sensitive DRA, both for navigation and to learn polarization patterns on flowers, the latter being the first nonnavigational function for bee polarization vision to be identified.
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
authors.forename: James J
authors.initials: JJ
authors.lastname: Foster
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
authors.forename: Camilla R
authors.initials: CR
authors.lastname: Sharkey
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
authors.forename: Alicia V A
authors.initials: AVA
authors.lastname: Gaworska
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Roberts
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Whitney
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK; School of Animal Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. Electronic address: j.c.partridge@bristol.ac.uk.
authors.forename: Julian C
authors.initials: JC
authors.lastname: Partridge
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D035264:Flowers; D007858:Learning; D008027:Light; D054817:Pollination; D014796:Visual Perception