Color vision pigment frequencies in wild tamarins (Saguinusspp.)

Abstract

The adaptive importance of polymorphic color vision found in many New World and some prosimian primates has been discussed for many years. Polymorphism is probably maintained in part through a heterozygote advantage for trichromatic females, as such individuals are observed to have greater foraging success when selecting ripe fruits against a background of forest leaves. However, recent work also suggests there are some situations in which dichromatic individuals may have an advantage, and that variation in color vision among individuals possessing different alleles may also be significant. Alleles that confer a selective advantage to individuals are expected to occur at a higher frequency in populations than those that do not. Therefore, analyzing the frequencies of color vision alleles in wild populations can add to our understanding of the selective advantages of some color vision phenotypes over others. With this aim, we used molecular techniques to determine the frequencies of color vision alleles in 12 wild tamarin groups representing three species of the genus Saguinus. Our results show that allele frequencies are not equal, possibly reflecting different selective regimes operating on different color vision phenotypes.

Detection of fruit by theCerrado's marmoset (Callithrix penicillata): modeling color signals for different background scenarios and ambient light intensities

“…Based on information of Table 5, our predictions would be that phenotype advantage would follow both demands for widely spaced and longer M/L pigments in trichromats, with phenotype 543/562 nm enjoying the larger benefit, 543/556 nm being the least profitable phenotype and 556/562 nm presenting an intermediate advantage. In concurrence with that, allele 562 nm would be the most frequent, followed by allele 543 nm and allele 556 nm, just as described for living populations of callitrichids (Rowe and Jacobs, 2004;Surridge et al, 2005).…”

Food search through the eyes of a monkey: A functional substitution approach for assessing the ecology of primate color vision

“…By the same reasoning, among dichromats (males and homozygous females) the red allele is suggested to be the most favorable variant as it is the most spectrally separated from the S photopigment (420 nm) common to all individuals. Compellingly, the red-shifted allele is often found at the highest frequency in wild populations (Hiramatsu et al, 2005;Surridge & Mundy, 2002;Surridge et al, 2005), but see (Cropp, Boinski, & Li, 2002).…”

New World Monkeys and Color

“…In particular, the allele specifying the callitrichid 556 nm pigment (Table I) was significantly underrepresented, comprising <20% of the total. A subsequent analysis of opsin genes from additional wild populations of Saguinus supports the inequality of allelic representation (Surridge et al 2005b). The samples are relatively large and are from many different sources.…”

“…If the surveys are representative, this may be the case for the callitrichid monkeys, in which the proportion of heterozygous females is not maximized and, perhaps more important, there is predicted to be an altered representation of the various retinal pigment complements. Examination of the distributions of opsin alleles among breeding groups of red-bellied tamarins (Saguinus labiatus) suggests that between males and females the opsin allele types are nonrandomly distributed (Surridge et al 2005b), which may arise from an inbreeding avoidance mechanism and could serve to maintain opsin polymorphisms. All of the aforementioned facts raise questions about how well monkeys with different pigment complements are adapted to make particular kinds of visual discriminations.…”