The Frequency of Occurrence of Acyclic Monoterpene Alcohols in the Chemical Environment does not Determine Olfactory Sensitivity in Nonhuman Primates

Using a conditioning paradigm, the olfactory sensitivity of five spider monkeys, three squirrel monkeys, and three pigtail macaques for six acyclic monoterpene alcohols that differ markedly in their frequency of occurrence in plant odors was assessed. The results showed that: (1) all three primate species have a well-developed olfactory sensitivity for acyclic monoterpene alcohols; (2) squirrel monkeys are significantly more sensitive for members of this class of odorants than the other two species and are able to detect all six odorants at concentrations below 0.1 ppm; and (3) there is a lack of positive correlations between olfactory sensitivity and the abundance of the acyclic monoterpene alcohols in flower odors and etheric oils. The results lend support to the growing body of evidence that suggests between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance. The findings do not support the hypothesis that olfactory sensitivity for members of a chemical class may be related to the frequency of occurrence of such odorants in a species' chemical environment.