Primates with three types of colour receptor in their eyes capture more insect prey than those whose eyes have two. But the latter are not without advantage — they are better at detecting and catching camouflaged prey.

The primates of mainland Africa and Asia all have three types of colour receptor, making them 'trichromats'. Some in the Americas can be trichromat or dichromat. Hannah Buchanan-Smith at the University of Stirling, UK, and her colleagues studied trichromatic and dichromatic tamarins (Saguinus spp.; pictured) in captivity and in the field.

Other research has shown that trichromacy may also assist primates in spotting ripe fruits and young leaves. The persistence of dichromacy may result from the advantage it provides in detecting concealed prey, the authors say.

Credit: J. DIEGMANN

Anim. Behav. http://dx.doi.org/10.1016/j.anbehav.2011.11.023 (2012)