Abstract
Terrestrial habitats exhibit a variety of light environments. If species exhibit evolutionary adaptations of their visual system or signals to habitat light conditions, then these conditions can directly influence the structure of communities. We evaluated habitat light characteristics and visual-signal design in a pair of sympatric species of lizards: Anolis cooki and Anolis cristatellus. We found that each species occupies a distinct microhabitat with respect to light intensity and spectral quality. We measured the relative retinal spectral sensitivity and found significant differences between the species that correlate with differences in habitat spectral quality. We measured the spectral reflectance of the dewlaps (colourful throat fans used in communication), and found that the A. cooki dewlap reflects little ultraviolet (UV), while that of A. cristatellus reflects strongly in the UV. For both species downwelling light (irradiance) is rich in UV. However the background light (radiance) is rich in UV for A. cooki, but low in UV for A. cristatellus. Thus, the dewlap of each species creates a high contrast with the background in the UV. Our findings strongly suggest that these two species are partitioning their habitat through specializations of the visual system and signal design to microhabitat light conditions.
Full Text
The Full Text of this article is available as a PDF (155.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Briscoe A. D., Chittka L. The evolution of color vision in insects. Annu Rev Entomol. 2001;46:471–510. doi: 10.1146/annurev.ento.46.1.471. [DOI] [PubMed] [Google Scholar]
- Chiao C. C., Vorobyev M., Cronin T. W., Osorio D. Spectral tuning of dichromats to natural scenes. Vision Res. 2000;40(23):3257–3271. doi: 10.1016/s0042-6989(00)00156-5. [DOI] [PubMed] [Google Scholar]
- Fleishman L. J., Persons M. The influence of stimulus and background colour on signal visibility in the lizard Anolis cristatellus. J Exp Biol. 2001 May;204(Pt 9):1559–1575. doi: 10.1242/jeb.204.9.1559. [DOI] [PubMed] [Google Scholar]
- Jacobs G. H., Neitz J., Krogh K. Electroretinogram flicker photometry and its applications. J Opt Soc Am A Opt Image Sci Vis. 1996 Mar;13(3):641–648. doi: 10.1364/josaa.13.000641. [DOI] [PubMed] [Google Scholar]
- LeBas N. R., Marshall N. J. The role of colour in signalling and male choice in the agamid lizard Ctenophorus ornatus. Proc Biol Sci. 2000 Mar 7;267(1442):445–452. doi: 10.1098/rspb.2000.1020. [DOI] [PMC free article] [PubMed] [Google Scholar]
- doi: 10.1098/rspb.1998.0315. [DOI] [PMC free article] [Google Scholar]
- Srinivasan M. V. Shouldn't directional movement detection necessarily be "colour-blind"? Vision Res. 1985;25(7):997–1000. doi: 10.1016/0042-6989(85)90210-x. [DOI] [PubMed] [Google Scholar]
- Thorpe R. S., Richard M. Evidence that ultraviolet markings are associated with patterns of molecular gene flow. Proc Natl Acad Sci U S A. 2001 Mar 20;98(7):3929–3934. doi: 10.1073/pnas.071576798. [DOI] [PMC free article] [PubMed] [Google Scholar]