Polymorphic Color Vision in Primates: Evolutionary Considerations

Abstract

Color provides a reliable cue for object detection and identification during various behaviors such as foraging, mate choice, predator avoidance, and navigation. The total number of colors that a visual system can discriminate is largely dependent on the number of different spectral types of cone opsins present in the retina and the spectral separations among them. Thus, opsins provide an excellent model system to study evolutionary interconnections at genetic, phenotypic, and behavioral levels. Primates have evolved a unique ability for three-dimensional color vision (trichromacy) from the two-dimensional color vision (dichromacy) present in the majority of other mammals. This development was accomplished via allelic differentiation (e.g., most New World monkeys) or gene duplication (e.g., Old World primates) of the middle to long wavelength-sensitive (M/LWS, or red–green) opsin gene. However, questions remain regarding the behavioral adaptations of primate trichromacy. Allelic differentiation of the M/LWS opsins results in extensive color vision variability in New World monkeys, where trichromats and dichromats are found in the same breeding population, enabling us to directly compare visual performances among different color vision phenotypes. Thus, New World monkeys can serve as an excellent model to understand and evaluate the adaptive significance of primate trichromacy in a behavioral context. In this chapter, we summarize recent findings on color vision evolution in primates and other vertebrates and introduce our genetic and behavioral study of vision–behavior interrelationships in free-ranging sympatric capuchin and spider monkey populations in Costa Rica.KeywordsColor VisionWorld MonkeySpider MonkeyCapuchin MonkeyHowler MonkeyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.