Olfactory sensitivity to food odor components in the short-tailed fruit bat, Carollia perspicillata (phyllostomatidae, chiroptera)

Abstract

The absolute olfactory sensitivity in a frui-teating bat, Carollia perspicillata, was investigated. Eighteen monomolecular food odor components from 3 substance classes were tested using a sniff rate analysis method. Detection thresholds (Table 1) ranged from 3.6 · 1013 to 2.7 · 1010 molecules/cm3 air. Interindividual variation (N = 4) for a substance did not exceed one order of magnitude. Significant correlations between olfactory performance and carbon chain length of the odor molecule were found for two substance classes: Sensitivity to the aliphatic iso-alcohols increased linearly from C2 to C5, and a nonlinear correlation was found for the acetic esters, with the C4- and C7-forms being clearly better perceived than the other homologues. In acetic esters, the sensitivity for the n-forms of the molecule was significantly higher than for the iso-forms. No such correlation between stereo-isomers and olfactory perception was found for the n- and iso-forms of carbon acids and aliphatic alcohols. Fruit-typical odor components like ethyl butyrate (5.4 · 1010), n-pentyl acetate (2.8 · 1010), or linalool (1.8 · 1011 molecules/cm3 air) were the most effective among all compounds tested, suggesting that the nutritional specialization of the bat may be associated with a specific spectrum of olfactory sensitivity.