Abstract: Electroantennograms were recorded from female Dendrolimus tabulaeformis Tsai et Liu to serial stimulus doses (50 μL, 100 μL, 400 μL, 800 μL, 1 600 μL, and 3 200 μL) of four monoterpene hydrocarbons (（+）-α-pinene, （-）-α- pinene, （-）-β- pinene, and （+）-β-pinene), and the saturating dose was tested. Dose-response curves constructed from the EAGs revealed that the saturating dose of （-）-α-pinene was 1 600 μL and that of the other three chemicals was 800 μL. The relative volume of the electroantennogram response was higher for （+）-α-pinene compared to （-）-α-pinene, suggesting that greater affinity to receptor molecules for （+）-α-pinene than (-)-α-pinene; on the contrary, response of the moth to the （-）form of the β-pinene was higher than that to the (+) form, suggesting that （+）-β-pinene does not bind as efficiently as （-）-β-pinene with the receptor molecules in many of the sensilla. Electroantennogram recording using mixtures of the enantiomers at saturating dose levels showed that the response to the mixture of α-pinene was almost equal to those of the two forms of α-pinene, suggesting that the two forms of α-pinene were detected by the same receptor neurons; and the same for the β-pinene. Discrimination between enantiomers by plant olfactory receptor neurons in the moth suggested that the enantiomeric ratios of volatile compounds might be important in host location of D. tabulaeformis.

Key words: Dendrolimus tabulaeformis, chiral monopene hydrocarbons, α-pinene, β-pinene, electroantennogram (EAG), dose response, saturating dose