Other
Scientific paper
Aug 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005spie.5888..204c&link_type=abstract
Polarization Science and Remote Sensing II. Edited by Shaw, Joseph A.; Tyo, J. Scott. Proceedings of the SPIE, Volume 5888, pp
Other
3
Scientific paper
Although natural light sources produce depolarized light, patterns of partially linearly polarized light appear in the sky due to scattering from air molecules, dust, and aerosols. Many animals, including bees and ants, orient themselves to patterns of polarization that are present in daytime skies, when the intensity is high and skylight polarization is strong and predictable. The halicitid bee Megalopta genalis inhabits rainforests in Central America. Unlike typical bees, it forages before sunrise and after sunset, when light intensities under the forest canopy are very low, and must find its way to food sources and return to its nest in visually challenging circumstances. An important cue for the orientation could be patterns of polarization in the twilight sky. Therefore, we used a calibrated digital camera to image skylight polarization in an overhead patch of sky, 87.6° across, before dawn on Barro Colorado Island in Panama, where the bees are found. We simultaneously measured the spectral properties of polarized light in a cloudless patch of sky 15° across centered on the zenith. We also performed full-sky imaging of polarization before dawn and after dusk on Lizard Island in Australia, another tropical island. During twilight, celestial polarized light occurs in a wide band stretching perpendicular to the location of the hidden sun and reaching typical degrees of polarization near 80% at wavelengths >600 nm. This pattern appears about 45 minutes before local sunrise or disappears 45 minutes after local sunset (about 20 minutes after the onset of astronomical twilight at dawn, or before its end at dusk) and extends with little change through the entire twilight period. Such a strong and reliable orientation cue could be used for flight orientation by any animal with polarization sensitivity that navigates during twilight.
Cronin Thomas W.
Greiner Birgit
Warrant Eric J.
No associations
LandOfFree
Polarization patterns of the twilight sky does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Polarization patterns of the twilight sky, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polarization patterns of the twilight sky will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-799872