spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online April 18, 2006
Journal of Experimental Biology 209, 1612-1616 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02196
This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tuthill, J. C.
Right arrow Articles by Johnsen, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tuthill, J. C.
Right arrow Articles by Johnsen, S.

Polarization sensitivity in the red swamp crayfish Procambarus clarkii enhances the detection of moving transparent objects

John C. Tuthill1 and Sönke Johnsen2,*

1 Biology Department, Swarthmore College, Swarthmore, PA 19081, USA
2 Biology Department, Duke University, Durham, NC 27708, USA


Figure 1
View larger version (27K):

[in a new window]
  		Fig. 1. Schematic diagram of the experimental apparatus used in the study. The PVC half-section of pipe is transparent in this figure to show the inside of the device. In the actual setup the polarizer/diffuser sheets were sandwiched together against the side of the tank.

 

Figure 2
View larger version (33K):

[in a new window]
  		Fig. 2. The target was constructed of clear acrylic covered with colorless, polarization-active Mylar. (A) Unmodified photograph of the transparent target viewed under polarized light. (B) Polarization contrast image of the target (trans-illuminated by vertically polarized light) generated by taking two photographs through a polarizing filter that was rotated by 90° between exposures. Each pixel brightness is equal to 255[(Iv–Ih)/(Iv+Ih)], where Iv and Ih are the pixel values when the transilluminated target is viewed through a vertical and horizontal polarizer respectively. (C) Same as in B but with wax-paper diffuser depolarizing the light. Because the neural responses of P. clarkii to changing e-vector depend on the rate of change (Glantz, 2001Go), and possibly on color, it is impossible to simulate how the moving target appears under each condition. Thus B and C are probably only an approximate indication of the contrast of the target under polarizing and non-polarizing conditions, respectively. The bar on right shows the contrast scale.

 

Figure 3
View larger version (13K):

[in a new window]
  		Fig. 3. Spectral irradiance inside the crayfish chamber under both polarization conditions. The irradiance probe faced the light source.

 

Figure 4
View larger version (9K):

[in a new window]
  		Fig. 4. Response of Procambarus clarkii to the approach of the target under polarized and unpolarized conditions (N=20 for each treatment). Crayfish retreated from the target significantly more often in the polarized condition (P<0.00005).

 




© The Company of Biologists Ltd 2006