Non-random association of opsin alleles in wild groups of red-bellied tamarins ( Saguinus labiatus ) and maintenance of the colour vision polymorphism

Abstract

The remarkable X-linked colour vision polymorphism observed in many New World primates is thought to be maintained by balancing selection. Behavioural tests support a hypothesis of heterozygote advantage, as heterozygous females (with trichromatic vision) exhibit foraging benefits over homozygous females and males (with dichromatic vision) when detecting ripe fruit on a background of leaves. Whilst most studies to date have examined the functional relevance of polymorphic colour vision in the context of foraging behaviour, alternative hypotheses proposed to explain the polymorphism have remained unexplored. In this study we examine colour vision polymorphism, social group composition and breeding success in wild red-bellied tamarins Saguinus labiatus . We find that the association of males and females within tamarin social groups is non-random with respect to colour vision genotype, with identified mating partners having the greatest allelic diversity. The observed distribution of alleles may be driven by inbreeding avoidance and implies an important new mechanism for maintaining colour vision polymorphism. This study also provides the first preliminary evidence that wild trichromatic females may have increased fitness compared with dichromatic counterparts, as measured by breeding success and longevity.

Spotting Fruit versus Picking Fruit as the Selective Advantage of Human Colour Vision

“…Because trichromacy arises from heterozygosity, rather than from possessing a single advantageous allele, it cannot be simply passed on to offspring. In fact, there is about equal chance of a dichromatic or trichromatic mother having a trichromatic daughter (in-breeding avoidance can complicate this, and possibly make dichromats more likely to have trichromatic daughters; Surridge, Suarez, Buchanan-Smith, & Mundy, 2005). …”

Polymorphism of visual pigment genes in the muriqui (Primates, Atelidae)

“…The absence of uniform trichromatic vision in Brachyteles, a seasonal folivore possessing a suite of morphological characteristics associated with leaf eating, obscures the adaptive importance of trichromatic vision for any particular food item (cf. Cropp et al 2002;Surridge et al 2005). Instead, trichromatic colour vision may allow for a range of visual advantages that could potentially serve to maintain the adaptation.…”

The Genetic and Evolutionary Drives behind Primate Color Vision

“…Color modeling studies have predicted that trichromats should outperform dichromats when discriminating socio-sexual signals (Sumner and Mollon, 2003;Changizi et al, 2006) and predators (Pessoa et al, 2014). The influence of color vision on sexual selection and social dynamics have been studied in Old World primates (Waitt et al, 2003;Changizi et al, 2006;Setchell et al, 2009;Gerald et al, 2010) and, to a lesser extent, in prosimians (Clough et al, 2009) and New World primates Surridge et al, 2005;Moreira et al, 2015). However, many studies may have overestimated animal color variation, by using subjective human perception when investigating other primate socio-reproductive signals (Higham et al, 2010).…”