Influência de pistas de forma e cor no forrageio de machos e fêmeas de saguis (Callithrixjacchus) cativos

Abstract

Primates use a variety of important sensory modalities in the extraction of environmental information. Olfaction, audition, touch, taste and vision are clearly present sensory channels. The sensory modality of vision is widely used in primates; the visual signal is directed to the visual córtex using functional parallelism. Color and shape information is decoded in different visual pathways that eventually converge, creating a competition during this processing. In primates is possible to notice a very trichromacy uniform, with the presence of three different photoreceptor cells in the single locus on the X chromosome gives dichromat and trichromat females and dichromat males. Behavior and field studies about genetics, electrophysiology and visual modeling suggest evolutionary hypotheses about the emergence of color vision. A classic hypothesis is related to foraging, suggesting an advantage to trichromats in detecting conspicuous targets, while dichromats have advantages in breach of camouflaged targets. Other hypotheses involve social behavior, mate choice, group dynamics, and avoidance of predators. These studies also suggest alternatives to the advantages of remaining this polymorphic condition in the population. None of the alternative proposals are fully accepted; although a gradual increase of the studies with color vision, it is still a relatively new area which requires further studies with different approaches. The present study aims to examine the importance of color and shape cues in foraging for food targets in male and female captive marmosets, Callithrix jacchus. Different situations were presented to animais in which food with spherical or cubic shape and green, orange or blue color were distributed on a green or camouflage background. The results showed a different pattern for males and females retina. New World primates exhibit a polymorphic condition whose the presence of a particular pattern depending on the type of color vision. Old World primates have a viii .Females were better at detecting targets orange, while males performed better when the target was hidden. This fact suggests a balance between the advantages and disadvantages of different visual phenotypes, which could explain the maintenance of visual polymorphism in primate species.