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Twilight orientation to polarised light in the crepuscular dung beetle Scarabaeus zambesianus

Dacke, Marie LU ; Nordstrom, P and Scholtz, CH (2003) In Journal of Experimental Biology 206(9). p.1535-1543
Abstract
The polarisation pattern of skylight offers many arthropods a reference for visual compass orientation. The dung beetle Scarabaeus zambesianus starts foraging at around sunset. After locating a source of fresh droppings, it forms a ball of dung and rolls it off at high speed to escape competition at and around the dung pile. Using behavioural experiments in the field and in the laboratory, we show that the beetle is able to roll along a straight path by using the polarised light pattern of evening skylight. The receptors used to detect this skylight cue can be found in the ommatidia of the dorsal rim area of the eye, whose structures differ from the regular ommatidia in the rest of the eye. The dorsal rim ommatidia are characterised by... (More)
The polarisation pattern of skylight offers many arthropods a reference for visual compass orientation. The dung beetle Scarabaeus zambesianus starts foraging at around sunset. After locating a source of fresh droppings, it forms a ball of dung and rolls it off at high speed to escape competition at and around the dung pile. Using behavioural experiments in the field and in the laboratory, we show that the beetle is able to roll along a straight path by using the polarised light pattern of evening skylight. The receptors used to detect this skylight cue can be found in the ommatidia of the dorsal rim area of the eye, whose structures differ from the regular ommatidia in the rest of the eye. The dorsal rim ommatidia are characterised by rhabdoms with microvilli oriented at only two orthogonal orientations. Together with the finding that the receptors do not twist along the length of the rhabdom, this indicates that the photoreceptors of the dorsal rim area are polarisation sensitive. Large rhabdoms, a reflecting tracheal sheath and a lack of screening pigments make this area of the eye well adapted for polarised light detection at low light levels. The fan-shaped arrangement of receptors over the dorsal rim area was previously believed to be an adaptation to polarised light analysis, but here we argue that it is simply a consequence of the way that the eye is built. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
rhabdom, Scarabaeus zambesianus, dung beetle, orientation, receptor, ommatidia, polarisation pattern, skylight
in
Journal of Experimental Biology
volume
206
issue
9
pages
1535 - 1543
publisher
The Company of Biologists Ltd
external identifiers
  • wos:000182804100020
  • pmid:12654892
  • scopus:0038735781
ISSN
1477-9145
DOI
10.1242/jeb.00289
language
English
LU publication?
yes
id
e96f4aef-293f-417e-a9fe-428a3a9c8d95 (old id 312031)
date added to LUP
2007-08-28 14:51:13
date last changed
2018-05-29 11:40:57
@article{e96f4aef-293f-417e-a9fe-428a3a9c8d95,
  abstract     = {The polarisation pattern of skylight offers many arthropods a reference for visual compass orientation. The dung beetle Scarabaeus zambesianus starts foraging at around sunset. After locating a source of fresh droppings, it forms a ball of dung and rolls it off at high speed to escape competition at and around the dung pile. Using behavioural experiments in the field and in the laboratory, we show that the beetle is able to roll along a straight path by using the polarised light pattern of evening skylight. The receptors used to detect this skylight cue can be found in the ommatidia of the dorsal rim area of the eye, whose structures differ from the regular ommatidia in the rest of the eye. The dorsal rim ommatidia are characterised by rhabdoms with microvilli oriented at only two orthogonal orientations. Together with the finding that the receptors do not twist along the length of the rhabdom, this indicates that the photoreceptors of the dorsal rim area are polarisation sensitive. Large rhabdoms, a reflecting tracheal sheath and a lack of screening pigments make this area of the eye well adapted for polarised light detection at low light levels. The fan-shaped arrangement of receptors over the dorsal rim area was previously believed to be an adaptation to polarised light analysis, but here we argue that it is simply a consequence of the way that the eye is built.},
  author       = {Dacke, Marie and Nordstrom, P and Scholtz, CH},
  issn         = {1477-9145},
  keyword      = {rhabdom,Scarabaeus zambesianus,dung beetle,orientation,receptor,ommatidia,polarisation pattern,skylight},
  language     = {eng},
  number       = {9},
  pages        = {1535--1543},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {Twilight orientation to polarised light in the crepuscular dung beetle Scarabaeus zambesianus},
  url          = {http://dx.doi.org/10.1242/jeb.00289},
  volume       = {206},
  year         = {2003},
}