The adaptive value of primate color vision for predator detection

Abstract

The complex evolution of primate color vision has puzzled biologists for decades. Primates are the only eutherian mammals that evolved an enhanced capacity for discriminating colors in the green-red part of the spectrum (trichromatism). However, while Old World primates present three types of cone pigments and are routinely trichromatic, most New World primates exhibit a color vision polymorphism, characterized by the occurrence of trichromatic and dichromatic females and obligatory dichromatic males. Even though this has stimulated a prolific line of inquiry, the selective forces and relative benefits influencing color vision evolution in primates are still under debate, with current explanations focusing almost exclusively at the advantages in finding food and detecting socio-sexual signals. Here, we evaluate a previously untested possibility, the adaptive value of primate color vision for predator detection. By combining color vision modeling data on New World and Old World primates, as well as behavioral information from human subjects, we demonstrate that primates exhibiting better color discrimination (trichromats) excel those displaying poorer color visions (dichromats) at detecting carnivoran predators against the green foliage background. The distribution of color vision found in extant anthropoid primates agrees with our results, and may be explained by the advantages of trichromats and dichromats in detecting predators and insects, respectively.

The Genetic and Evolutionary Drives behind Primate Color Vision

“…On the other hand, the same yellow-coated predators may also contrast with the green foliage background, enabling their detection by chromatic information, favoring trichromats. Through color vision modeling and behavioral experiments, the only study to test the predator detection hypothesis to date demonstrated that trichromats excel over dichromats when searching for camouflaged predators (Pessoa et al, 2014). This study suggests that the diversity and distribution of color vision in extant anthropoid taxa could reflect the selective advantages of trichromats and dichromats in detecting predators (Pessoa et al, 2014) and cryptic insects (Melin et al, 2007), respectively.…”

“…Through color vision modeling and behavioral experiments, the only study to test the predator detection hypothesis to date demonstrated that trichromats excel over dichromats when searching for camouflaged predators (Pessoa et al, 2014). This study suggests that the diversity and distribution of color vision in extant anthropoid taxa could reflect the selective advantages of trichromats and dichromats in detecting predators (Pessoa et al, 2014) and cryptic insects (Melin et al, 2007), respectively. The color vision polymorphism of New World primates would be expected therefore to have developed in small anthropoids, since these small bodied primates tend to include more insects and fewer leaves in their diets (Fleagle, 1999).…”

“…In fact, a few studies suggest that color may not even play an essential role in primate short distance food detection (Hiramatsu et al, 2008Bompas et al, 2013), so other selective forces (e.g., detection of predators; sexual selection and social dynamics) should be examined. 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).…”

Platyrrhine color signals: New horizons to pursue

“…With few exceptions the entire body of work on platyrrhine color vision has assessed color vision variation through the lens of potential foraging adaptations. Although color vision has been linked to food detection and feeding efficiencies, without an assessment of possible roles of color in socio‐sexual signaling, it is challenging to thoroughly assess the relative importance of diet in influencing color vision evolution.…”

Howler monkey foraging ecology suggests convergent evolution of routine trichromacy as an adaptation for folivory

“…Chromaticity plots and calculations of just-noticeable differences (JNDs) are widely used in the study of primate visual ecology (Higham et al, 2010;Hiramatsu et al, 2009;Melin, Hiramatsu et al, 2014;Osorio, Smith, Vorobyev, Buchanan-Smith, & Ryan, 2004;Osorio & Vorobyev, 1996;Pessoa et al, 2014;Valenta et al, 2015). We calculated the quantum catch of photons by the LWS, MWS, and SWS cones following established methods, reported in detail elsewhere (Hiramatsu et al, 2008;Matsumoto et al, 2014).…”