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 October 31, 2008
Journal of Experimental Biology 211, 3536-3543 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.022277
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 Related articles in JEB
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 Lerner, A.
Right arrow Articles by Broza, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lerner, A.
Right arrow Articles by Broza, M.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Reflected polarization guides chironomid females to oviposition sites

Amit Lerner1,*, Nikolay Meltser2, Nir Sapir3, Carynelisa Erlick1, Nadav Shashar4 and Meir Broza2

1 Department of Atmospheric Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
2 Faculty of Science and Science Education, University of Haifa at Oranim, Tivon 36006, Israel
3 Department of Evolution, Systematics and Ecology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
4 Department of Life Sciences, Eilat Campus, Ben-Gurion University, Hatmarim St., Elat 88000, Israel


Figure 1
View larger version (198K):
[in this window]
[in a new window]

  		Fig. 1. An egg trap used in experiment 1. The trap consisted of a 30 cmx30 cmx30 cm wooden box, on the bottom of which was a 10 W bulb. Above the bulb there was a 10 cmx10 cm open hatch with a 15 cmx15 cm filter (black rectangle). The filter included diffusers and a plane polarizer that provided polarized/unpolarized illumination at two levels of intensity. A 15 cmx15 cmx10 cm glass aquarium filled with 2 cm (450 cm3) of tap water was placed on the filter.

 

Figure 2
View larger version (13K):
[in this window]
[in a new window]

  		Fig. 2. Intensity (solid lines) and percentage polarization (dashed lines) of radiation measured in the range 490—510 nm reflected from the egg traps in experiment 1. The light source was a 10 W bulb. PLIL, polarization low (unpolarized) intensity low [1 polarizing sheet (1p) + 15 diffusing sheets (15d)] ordered from light source to viewer; PLIH, polarization low intensity high (1p + 3d); PHIL, polarization high (polarized) intensity low (15d + 1p); PHIH, polarization high intensity high (3d + 1p).

 

Figure 3
View larger version (10K):
[in this window]
[in a new window]

  		Fig. 3. The spectrum of intensity (dashed grey line, measured without a polarizing filter), percentage polarization (black solid line) and e-vector orientation (grey solid line) reflected from the pond's surface, measured on 17 October 2007 at 16.23 h local time (UTC+2 h). The sun was obscured by the Carmel Ridge from 16.00 h and sunset time was 17.05 h. The sensor was directed 45 deg. from the nadir and 230 deg. from the north. The intensity, percentage polarization and e-vector orientation calculated from the readings integrated over the range 490—510 nm were 2.8x10—3 µEcm—2 s—1, 71.5%, and 4.4 deg., respectively (where 0 deg. represents horizontal alignment).

 

Figure 4
View larger version (25K):
[in this window]
[in a new window]

  		Fig. 4. Mean ± s.d. of the intensity (A) and percentage polarization (B), reflected from the four tubs in experiment 2, as a function of wavelength in the range 490—510 nm. WT, black tub painted white up to water level filled with tap water (N=10; 10 tubs, one measurement from each tub); WP, black tub painted white up to water level filled with pond water (N=10); BT, black tub filled with tap water (N=18); and BP, black tub filled with pond water (N=18). For the reflected intensity, only WT differed significantly from the other tubs (Kruskal—Wallis non-parametric ANOVA; P<0.05). For the reflected percentage polarization, only BT and BP did not differ significantly from each other (pair-wise comparisons, one-way ANOVA, P<0.001). None of the e-vector orientations reflected from the tubs differed significantly from 0 deg. (horizontal).

 

Figure 5
View larger version (9K):
[in this window]
[in a new window]

  		Fig. 5. Intensity (triangles), percentage polarization (circles), and e-vector orientation (diamonds) of the radiance reflected from the pond water surface during sunset, measured on December 10, 2007. Values were measured for the wavelength range 490—510 nm. The sun was obscured by the Carmel Ridge at 15.57 h local time (black vertical bar) and sunset time was 16.36 h (grey vertical bar). Complete darkness occurred at 17.01 h. The e-vector orientation did not differ from horizontal (0±4 deg.). Note that the light intensity decreased by 96%, while the percentage polarization remained stable at around 60%.

 

Figure 6
View larger version (87K):
[in this window]
[in a new window]

  		Fig. 6. Chironomid egg batch (EB) types and their relative contribution (%) to the total eggs laid in experiment 1. (A) An unidentified genus of chironomids (0.1%), (B) Kiefferulus sp. (6.3%), (C) Chironomus transvaalensis (83.5%), and (D) Polypedilum nubifer (10.1%). Note that in experiment 2 conducted outdoors, only C. transvaalensis eggs were found.

 

Figure 7
View larger version (3K):
[in this window]
[in a new window]

  		Fig. 7. Mean ± s.d. of percentages of egg batches (EB) laid in artificial egg traps in experiment 1 (total EB=10592; N=10 repeats). Planned comparison of means of PLIL vs PLIH, PLIL vs PHIL, PHIL vs PHIH, and PLIH vs PHIH were found significant in all four pairs (P<0.005). PLIL, polarization low (unpolarized) intensity low; PLIH, polarization low intensity high; PHIL, polarization high (polarized) intensity low; PHIH, polarization high intensity high.

 

Figure 8
View larger version (3K):
[in this window]
[in a new window]

  		Fig. 8. Mean ± s.d. of percentages of egg batches (EB) laid in the tubs in experiment 2 (total EB=3543; N=16 repeats). A Bonferroni post-hoc test revealed a significant difference between all treatments (P<0.05). Note that EB laid in WT (black tub painted white up to water level and filled with tap water) was not significantly different from 0%. WP, black tub painted white up to water level filled with pond water; BT, black tub filled with tap water; BP, black tub filled with pond water.

 

Figure 9
View larger version (10K):
[in this window]
[in a new window]

  		Fig. 9. Intensity (triangles), percentage polarization (circles), and e-vector orientation (diamonds) of the radiance reflected from a 70 l white barrel filled with 60 l of pond water versus the total organic carbon (TOC) concentration measured in the water. Values were measured for the wavelength range 490—510 nm. The e-vector orientation did not differ significantly from horizontal (—6±17 deg.). A value of TOC=0 mg l—1 was excluded, since the corresponding reflected radiance was almost unpolarized (percentage polarization=2.6%).

 

Figure 10
View larger version (75K):
[in this window]
[in a new window]

  		Fig. 10. (A) Transmission electron micrograph (TEM) of a transverse section of an ommatidium from the ventral part (white arrow in B) of the Chironomus transvaalensis female eye. The double-headed black arrows in A indicate the general alignment of the microvilli of rhabdomeres R1—R7. Note that the microvilli of R4 and R7 are orthogonal to the microvilli of R1 and R2, and both are aligned at 45 deg. with respect to R5,R6 and R3, providing the anatomical basis for linear polarization detection.

 

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?



© The Company of Biologists Ltd 2008