1Department of Anthropology, University of Texas at Austin, 2Population Research Center, University of Texas at Austin
Friday 3:45-4:00, Ballroom C
While polymorphic trichromacy is well-documented in platyrrhines, recent work suggests it is also common among lemurs. In this form of color vision, allelic variation at the X-chromosome M/L opsin locus results in separate green- and red-sensitive cones in heterozygous females (trichromacy) but a single M/L cone type in homozygous females and males (dichromacy). Although polymorphic trichromacy is thought to be selectively advantageous in foraging, platyrrhine field studies have generally failed to identify any significant effect of color vision phenotype on foraging behavior. However, these studies have focused on insectivorous-frugivorous species. We examined the influence of color vision phenotype on foraging in a folivorous diurnal lemur, Verreaux’s sifaka (Propithecus verreauxi). Previous work identified a polymorphism in Propithecus causing either “green-sensitive” (543 nm) or “red-sensitive” (558 nm) alleles. We collected genomic DNA from 50 individuals (28 females, 22 males) across 8 social groups at Kirindy Mitea National Park, a dry, deciduous forest in Madagascar. Using a custom assay, we performed real-time polymerase chain reactions to genotype each individual. Approximately 540 hours of foraging data were collected over 12 months on 10 focal individuals.
We detected evidence of polymorphic trichromacy in this population. Six (~21%) females were heterozygous for green- and red-sensitive alleles. The red-sensitive allele had the highest frequency (84% of 71 chromosomes). However, preliminary analyses of foraging behavior did not identify a significant relationship between color vision phenotype and plant parts consumed in Propithecus. The evolutionary significance of polymorphic trichromacy therefore remains uncertain, but may benefit from further studies of strepsirrhines.