title: Flying Drosophila orient to sky polarization.
abstract: Insects maintain a constant bearing across a wide range of spatial scales. Monarch butterflies and locusts traverse continents [1, 2], and foraging bees and ants travel hundreds of meters to return to their nests [1, 3, 4], whereas many other insects fly straight for only a few centimeters before changing direction. Despite this variation in spatial scale, the brain region thought to underlie long-distance navigation is remarkably conserved [5, 6], suggesting that the use of a celestial compass is a general and perhaps ancient capability of insects. Laboratory studies of Drosophila have identified a local search mode in which short, straight segments are interspersed with rapid turns [7, 8]. However, this flight mode is inconsistent with measured gene flow between geographically separated populations [9-11], and individual Drosophila can travel 10 km across desert terrain in a single night [9, 12, 13]-a feat that would be impossible without prolonged periods of straight flight. To directly examine orientation behavior under outdoor conditions, we built a portable flight arena in which a fly viewed the natural sky through a liquid crystal device that could experimentally rotate the polarization angle. Our findings indicate that Drosophila actively orient using the sky's natural polarization pattern.
authors.affiliation: Computation and Neural Systems, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Weir
authors.forename: Michael H
authors.initials: MH
authors.lastname: Dickinson
mesh_terms: D000818:Animals; D004330:Drosophila / Q000502:physiology*; D005426:Flight, Animal; D008027:Light; D009949:Orientation