|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online October 5, 2007
Journal of Experimental Biology 210, 3624-3635 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.006932
Spectral and spatial properties of polarized light reflections from the arms of squid (Loligo pealeii) and cuttlefish (Sepia officinalis L.)
1 Department of Biological Sciences, University of Maryland, Baltimore
County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
2 Marine Resources Center, Marine Biological Laboratory, Woods Hole, MA
02543, USA
* Author for correspondence (e-mail: chiou1{at}umbc.edu)
Accepted 16 July 2007
On every arm of cuttlefish and squid there is a stripe of high-reflectance iridophores that reflects highly polarized light. Since cephalopods possess polarization vision, it has been hypothesized that these polarized stripes could serve an intraspecific communication function. We determined how polarization changes when these boneless arms move. By measuring the spectral and polarizing properties of the reflected light from samples at various angles of tilt and rotation, we found that the actual posture of the arm has little or no effect on partial polarization or the e-vector angle of the reflected light. However, when the illumination angle changed, the partial polarization of the reflected light also changed. The spectral reflections of the signals were also affected by the angle of illumination but not by the orientation of the sample. Electron microscope samples showed that these stripes are composed of several groups of multilayer platelets within the iridophores. The surface normal to each group is oriented at a different angle, which produces essentially constant reflection of polarized light over a range of viewing angles. These results demonstrate that cuttlefish and squid could send out reliable polarization signals to a receiver regardless of arm orientation.
Key words: cephalopod, polarized light, squid, cuttlefish, signal, iridophore, structural color
Related articles in JEB:
This article has been cited by other articles:
![]() |
L. Blackburn CONSTANT REFLECTIONS J. Exp. Biol., October 15, 2007; 210(20): iii - iii. [Full Text] [PDF] |
||||