Colour Discrimination in the Black-Tufted-Ear Marmoset (Callithrix penicillata): Ecological Implications

Abstract

The dietary diversity of marmosets is substantial, which may reflect differences in their colour vision. This study examined the colour discrimination ability of a gummivore/insectivore callitrichid, Callithrix penicillata, which inhabits the Brazilian cerrado (bush savanna). A series of ecologically relevant tasks, involving a behavioural paradigm of discrimination learning in semi-natural conditions and the usage of ecologically relevant stimuli, was executed. Three marmosets, 2 males and a female, behaved like human dichromats, showing an impaired performance when orange and green stimuli had to be discriminated. In contrast, 2 females resembled human trichromats, discriminating those kinds of pairs. Our data suggest that Callithrix penicillata presents a polymorphic trichromacy, with dichromatic males and dichromatic or trichromatic females.

Behavioural Evidence of Sex-Linked Colour Vision Polymorphism in the Squirrel Monkey Saimiri ustus

“…The movable screen prevented the subjects from seeing the stimuli in between trials. An illustration of a similar version of this apparatus can be found in Pessoa et al [2005a]. Natural diffuse sunlight illuminated the equipment.…”

“…The monkeys are found in a wide range of habitats, including primary forests, sec-ondary forests, dry forests, dry land tropical forests and temporarily flooded forests, at altitudes varying from 0 to 2,000 m, which allows them such a vast geographical distribution [Hershkovitz, 1984]. This study's goal was to investigate the ability of S. ustus to discriminate ecologically relevant colours through a behavioural paradigm which has proved to be effective in revealing colour vision phenotypes in other New World monkey species [Gomes et al, 2002;Pessoa et al, 2003Pessoa et al, , 2005a.…”

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

“…Almost 65% of the fruits exploited by this marmoset have been categorized as cryptic and more than 40% are dark (Pessoa et al, 2005a), possibly not detectable by color . Based on these facts, this species seems to be a good model for studying the differential advantages enjoyed by each color vision phenotype under natural conditions.…”

Color vision in marmosets and tamarins: behavioral evidence

“…Recent studies successfully used stimuli in this same spectral reflectance range to assess the color vision of dichromatic and trichromatic primates [Caine & Mundy, 2000;Gomes et al, 2002;Pessoa et al, 2003Pessoa et al, , 2005aSmith et al, 2003]. Similarly to natural elements, Munsell color chips show wide and complex surface reflectance functions [Pessoa et al, 2003] and varying brightness levels.…”

“…A plexiglas version of the Wisconsin General Test Apparatus [Pessoa et al, 2005a] was used to assess the color perception of the callitrichids. The animals had to perform two choice discrimination tasks between a positive discriminative stimulus (SD1, the rewarded stimulus) and a negative discriminative stimulus (SD-, never rewarded).…”