robert karl stonjek

Photoreceptor spectral sensitivities in terrestrial animals: adaptations for
luminance and colour vision

D. Osorio A1 and M. Vorobyev A2

A1 School of Life Sciences, University of Sus***, Brighton BN1 9QG, UK
A2 Vision, Touch and Hearing Research Centre, School of Biomedical Sciences,
University of Queensland, Brisbane, Queensland 4072, Australia

Abstract:

This review outlines how eyes of terrestrial vertebrates and insects meet
the competing requirements of coding both spatial and spectral information.
There is no unique solution to this problem. Thus, mammals and honeybees use
their long-wavelength receptors for both achromatic (luminance) and colour
vision, whereas flies and birds probably use separate sets of photoreceptors
for the two purposes. In particular, we look at spectral tuning and
diversification among 'long-wavelength' receptors (sensitivity maxima at
greater than 500nm), which play a primary role in luminance vision. Data on
spectral sensitivities and phylogeny of visual photopigments can be
incorporated into theoretical models to suggest how eyes are adapted to
coding natural stimuli. Models indicate, for example, that animal colour
vision-involving five or fewer broadly tuned receptors-is well matched to
most natural spectra. We can also predict that the particular objects of
interest and signal-to-noise ratios will affect the optimal eye design.
Nonetheless, it remains difficult to account for the adaptive significance
of features such as co-expression of photopigments in single receptors,
variation in spectral sensitivities of mammalian L-cone pigments and the
diversification of long-wavelength receptors that has occurred in several
terrestrial lineages.

Abstract and full text links at The Royal Society
http://tinyurl.com/a3uat

Posted by
Robert Karl Stonjek