Behavioral Ecology Advance Access originally published online on September 11, 2008
Behavioral Ecology 2009 20(1):1-12; doi:10.1093/beheco/arn106
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Seeing red: behavioral evidence of trichromatic color vision in strepsirrhine primates
a Department of Biology, Duke University, Durham, NC 27708, USA b Department of Animal Ecology and Tropical Biology, Julius-Maximilians-Universität, Würzburg 97074, Germany c Department of Evolutionary Anthropology, 129 Biological Sciences Building, Box 90383, Duke University, Durham, NC 27708, USA
Address correspondence to C.M. Drea. E-mail: cdrea{at}duke.edu.
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Abstract |
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Among primates, catarrhines (Old World monkeys and apes) and certain platyrrhines (New World monkeys) possess trichromatic color vision, which might confer important evolutionary advantages, particularly during foraging. Recently, a polymorphism has been shown to shift the spectral sensitivity of the X-linked opsin protein in certain strepsirrhines (e.g., Malagasy lemurs); however, its behavioral significance remains unknown. We assign genotypes at the X-linked variant to 45 lemurs, representing 4 species, and test if the genetic capacity for trichromacy impacts foraging performance, particularly under green camouflage conditions in which red detection can be advantageous. We confirm polymorphism at the critical site in sifakas and ruffed lemurs and fail to find this polymorphism in collared lemurs and ring-tailed lemurs. We show that this polymorphism may be linked to "behavioral trichromacy" in heterozygous ruffed lemurs but find no comparable evidence in a single heterozygous sifaka. Despite their putative dichromatic vision, female collared lemurs were surprisingly efficient at retrieving both red and green food items under camouflage conditions. Thus, species-specific feeding ecologies may be as important as trichromacy in influencing foraging behavior. Although the lemur opsin polymorphism produced measurable behavioral effects in at least one species, the ruffed lemur, these effects were modest, consistent with the modest shift in spectral sensitivity. Additionally, the magnitude of these effects varied across individuals of the same genotype, emphasizing the need for combined genetic and behavioral studies of trichromatic vision. We conclude that trichromacy may be only one of several routes toward increased foraging efficiency in visually complex environments.
Key words: dichromacy, feeding ecology, lemurs, opsin gene polymorphism, trichromacy.
* These authors contributed equally to this work
Received 27 December 2007; revised 16 July 2008; accepted 23 July 2008.