Fig. 3.

Electrophysiological response of (A) male and (B) female antennae of D. pini to sex pheromone components. Acetate: (2S,3R,7R)-3,7-dimethyl-2-tridecanyl acetate. Propionate: (2S,3R,7R)-3,7-dimethyl-2-tridecanyl propionate. Data show the responses to 500 ng of each pheromone component tested separately (acetate, propionate), or to a blend of both components (acetate + propionate) with 500 ng of each component, that is, 1,000 ng of pheromone in total. Each test odor (acetate, propionate, or the blend) was offered to n = 8 antennae of each sex. Data show means + SE of responses normalized to responses to ambient air and hexane, which were set to value 1 (dashed line). The antennal response to air was almost the same as the one to hexane. Statistical difference of the response to the pheromone from the response to air/hexane was evaluated by the Wilcoxon matched pairs test (**P < 0.01) (compare SI Appendix, Table S8).