Abstract # 5:

Scheduled for Thursday, August 18, 2005 10:30 AM-10:45 AM: Session 1 (Parliament Room) Oral Presentation

The effect of sex and colour vision status on prey capture by captive and wild tamarins (Saguinus spp.)

H. M. Buchanan-Smith1, A. C. Smith1,2, A. K. Surridge3, M. J. Prescott1,4, D. Osorio5 and N. I. Mundy6
1University of Stirling, Department of Psychology, Stirling, Scotland FK9 4LA, United Kingdom, 2Life Sciences, APU, East Road, Cambridge, CB1 1PT, England., 3School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, England., 4National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), 20 Park Crescent, London, W1B 1AL, England, 5Department of Biological Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, England, 6Department of Zoology, Downing St, University of Cambridge, Cambridge, CB2 3EJ, England.
     Most New World primates, and some strepsirhines, make excellent models to understand color vision as they are polymorphic. Trichromatic vision is achieved through the presence of multiple alleles at a single X-chromosome-linked opsin locus, and therefore only heterozygous females can be trichromatic; homozygous females and males are dichromatic. In such species, comparisons can be made of different color vision phenotypes, and within sexes avoiding potential sex difference confounds. Trichromacy has been shown to be advantageous over dichromacy for detecting and selecting certain foods, especially ripe fruits and young leaves amongst mature leaves. No previous study has examined how color vision affects prey capture. In an experiment with captive tamarins (Saguinus spp.), in which a locust was placed in their enclosure, females caught more prey than males (27 vs 14, binomial test, P < 0.05), and trichromats caught more than dichromats (38 vs 17, binomial test, P < 0.05). Similarly wild trichromatic tamarin females caught twice as many prey as their dichromatic counterparts; this could not be attributed to the higher energetic demands of breeding. However, the proportion of prey eaten with different defense class strategies was not the same for trichromats and dichromats. Camouflaged insects (leaf and bark mimics) made up 43% of the insect diet of dichromats, compared with only 13% for trichromats who had a greater proportion of green generalists and concealed insects in their diet. These findings support the maintenance of the color vision polymorphism through heterozygote advantage.