Abstract
Nocturnal animals are said to sacrifice colour vision in favour of increased absolute sensitivity. This is true for most vertebrates that possess a dual retina with a single type of rod for colour-blind night vision and multiple types of cone for diurnal colour vision. However, among the nocturnal vertebrates, geckos are unusual because they have no rods but three cone types. Here, we show that geckos use their cones for colour vision in dim light. Two specimens of the nocturnal helmet gecko Tarentola (formerly Geckonia) chazaliae were able to discriminate blue from grey patterns by colour alone. Experiments were performed at 0.002 cd m(-2), a light intensity similar to dim moonlight. We conclude that nocturnal geckos can use cone-based colour vision at very dim light levels when humans rely on colour-blind rod vision.
Full Text
The Full Text of this article is available as a PDF (107.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Kelber Almut, Balkenius Anna, Warrant Eric J. Scotopic colour vision in nocturnal hawkmoths. Nature. 2002 Oct 31;419(6910):922–925. doi: 10.1038/nature01065. [DOI] [PubMed] [Google Scholar]
- Kelber Almut, Vorobyev Misha, Osorio Daniel. Animal colour vision--behavioural tests and physiological concepts. Biol Rev Camb Philos Soc. 2003 Feb;78(1):81–118. doi: 10.1017/s1464793102005985. [DOI] [PubMed] [Google Scholar]
- Kröger R. H., Campbell M. C., Fernald R. D., Wagner H. J. Multifocal lenses compensate for chromatic defocus in vertebrate eyes. J Comp Physiol A. 1999 Apr;184(4):361–369. doi: 10.1007/s003590050335. [DOI] [PubMed] [Google Scholar]
- Liebman P. A., Entine G. Visual pigments of frog and tadpole (Rana pipiens). Vision Res. 1968 Jul;8(7):761–775. doi: 10.1016/0042-6989(68)90128-4. [DOI] [PubMed] [Google Scholar]
- Loew E. R., Govardovskii V. I., Röhlich P., Szél A. Microspectrophotometric and immunocytochemical identification of ultraviolet photoreceptors in geckos. Vis Neurosci. 1996 Mar-Apr;13(2):247–256. doi: 10.1017/s0952523800007483. [DOI] [PubMed] [Google Scholar]
- Osorio D., Vorobyev M., Jones C. D. Colour vision of domestic chicks. J Exp Biol. 1999 Nov;202(Pt 21):2951–2959. doi: 10.1242/jeb.202.21.2951. [DOI] [PubMed] [Google Scholar]
- Röll B. Gecko vision-visual cells, evolution, and ecological constraints. J Neurocytol. 2000 Jul;29(7):471–484. doi: 10.1023/a:1007293511912. [DOI] [PubMed] [Google Scholar]
- Stavenga D. G., Smits R. P., Hoenders B. J. Simple exponential functions describing the absorbance bands of visual pigment spectra. Vision Res. 1993 May;33(8):1011–1017. doi: 10.1016/0042-6989(93)90237-q. [DOI] [PubMed] [Google Scholar]