Limits...
A functional role of the sky's polarization pattern for orientation in the greater mouse-eared bat.

Greif S, Borissov I, Yovel Y, Holland RA - Nat Commun (2014)

Bottom Line: One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism.Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment.This renders bats the only mammal known so far to make use of the polarization pattern in the sky.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK [2] Sensory Ecology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany.

ABSTRACT
Animals can call on a multitude of sensory information to orient and navigate. One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism. Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment. This renders bats the only mammal known so far to make use of the polarization pattern in the sky. Although there is currently no clear understanding of how this cue is perceived in this taxon, our observation has general implications for the sensory biology of mammalian vision.

No MeSH data available.


Related in: MedlinePlus

Vanishing bearings of the bats.North (0°) is always at the top of the circles, except for a. The dashed circle depicts the Rayleigh significance threshold (P=0.05) and the arrows are the mean vector. The axial distribution of PS is shown by a double arrow. The triangle on the outside of the circles indicates the home direction. a is a 360° view of the sky with sunset and the experimental conditions. The dark bars represent the band of maximum polarization, mimicked by the filters. PN presents a natural polarization direction pattern, which is shifted 90° in PS. The bars on top of the experimental boxes symbolize the axis of vertical polarization in the windows. b are the control bats for RS1 (CC) that were untreated. c and d show the PN and PS data for release site 1 (RS1) and e and f for release site 2 (RS2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4109006&req=5

f1: Vanishing bearings of the bats.North (0°) is always at the top of the circles, except for a. The dashed circle depicts the Rayleigh significance threshold (P=0.05) and the arrows are the mean vector. The axial distribution of PS is shown by a double arrow. The triangle on the outside of the circles indicates the home direction. a is a 360° view of the sky with sunset and the experimental conditions. The dark bars represent the band of maximum polarization, mimicked by the filters. PN presents a natural polarization direction pattern, which is shifted 90° in PS. The bars on top of the experimental boxes symbolize the axis of vertical polarization in the windows. b are the control bats for RS1 (CC) that were untreated. c and d show the PN and PS data for release site 1 (RS1) and e and f for release site 2 (RS2).

Mentions: Bats use echolocation to orient and navigate. However, this sensory system is only sufficient for a short range of 5–50 m1213. For longer range navigation bats must use different sensory input such as vision1415. Furthermore, it has been demonstrated that bats can use the Earth’s magnetic field to orient and calibrate it against cues obtained at sunset1617. These could be the position of the sun, or as used in birds, the pattern of polarized light. The polarization pattern is strongest at dusk and dawn. At this time a band of maximum polarization stretches 90° east from the position of the sun over the zenith to 90° west of the sun and gets weaker towards and away from the sun) (see natural polarization direction (PN) in Fig. 1a). On the horizon this band is aligned vertically, as is the e-vector of polarization210. To test the hypothesis that bats calibrate a magnetic compass with polarized light cues we conducted translocation experiments with 70 adult female greater mouse-eared bats (Myotis myotis). Prior to release, the bats could observe the sky at sunset in experimental boxes with different manipulations of the polarization pattern (natural (PN) versus 90° shifted polarization directions (PS) orientation of the band of maximum polarization).


A functional role of the sky's polarization pattern for orientation in the greater mouse-eared bat.

Greif S, Borissov I, Yovel Y, Holland RA - Nat Commun (2014)

Vanishing bearings of the bats.North (0°) is always at the top of the circles, except for a. The dashed circle depicts the Rayleigh significance threshold (P=0.05) and the arrows are the mean vector. The axial distribution of PS is shown by a double arrow. The triangle on the outside of the circles indicates the home direction. a is a 360° view of the sky with sunset and the experimental conditions. The dark bars represent the band of maximum polarization, mimicked by the filters. PN presents a natural polarization direction pattern, which is shifted 90° in PS. The bars on top of the experimental boxes symbolize the axis of vertical polarization in the windows. b are the control bats for RS1 (CC) that were untreated. c and d show the PN and PS data for release site 1 (RS1) and e and f for release site 2 (RS2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109006&req=5

f1: Vanishing bearings of the bats.North (0°) is always at the top of the circles, except for a. The dashed circle depicts the Rayleigh significance threshold (P=0.05) and the arrows are the mean vector. The axial distribution of PS is shown by a double arrow. The triangle on the outside of the circles indicates the home direction. a is a 360° view of the sky with sunset and the experimental conditions. The dark bars represent the band of maximum polarization, mimicked by the filters. PN presents a natural polarization direction pattern, which is shifted 90° in PS. The bars on top of the experimental boxes symbolize the axis of vertical polarization in the windows. b are the control bats for RS1 (CC) that were untreated. c and d show the PN and PS data for release site 1 (RS1) and e and f for release site 2 (RS2).
Mentions: Bats use echolocation to orient and navigate. However, this sensory system is only sufficient for a short range of 5–50 m1213. For longer range navigation bats must use different sensory input such as vision1415. Furthermore, it has been demonstrated that bats can use the Earth’s magnetic field to orient and calibrate it against cues obtained at sunset1617. These could be the position of the sun, or as used in birds, the pattern of polarized light. The polarization pattern is strongest at dusk and dawn. At this time a band of maximum polarization stretches 90° east from the position of the sun over the zenith to 90° west of the sun and gets weaker towards and away from the sun) (see natural polarization direction (PN) in Fig. 1a). On the horizon this band is aligned vertically, as is the e-vector of polarization210. To test the hypothesis that bats calibrate a magnetic compass with polarized light cues we conducted translocation experiments with 70 adult female greater mouse-eared bats (Myotis myotis). Prior to release, the bats could observe the sky at sunset in experimental boxes with different manipulations of the polarization pattern (natural (PN) versus 90° shifted polarization directions (PS) orientation of the band of maximum polarization).

Bottom Line: One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism.Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment.This renders bats the only mammal known so far to make use of the polarization pattern in the sky.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK [2] Sensory Ecology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany.

ABSTRACT
Animals can call on a multitude of sensory information to orient and navigate. One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism. Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment. This renders bats the only mammal known so far to make use of the polarization pattern in the sky. Although there is currently no clear understanding of how this cue is perceived in this taxon, our observation has general implications for the sensory biology of mammalian vision.

No MeSH data available.


Related in: MedlinePlus