Abstract: A method measuring EAG (electroantennogram) response in lamellate antennae of Holotrichia parallela Motschulsky was established in this study. A higher value of EAG was got when lamellae were separated from each other by insect pin. With the concentration of 30 ng·μL^-1, the EAG value of male antennae reached the maximum when the volume ratio of L-isoleucine methyl ester (LIME) to (R)-(-)-linalool was 7∶1, which was almost equal to the EAG value of the crude extracts from 25 sex glands. The male antennae were treated with different concentrations of stimulative reagent with the fixed volume ratio (7∶1) of LIME to (R)-(-)-linalool. The highest EAG value of male antennae was found when the concentration was 30 ng·μL^-1. The results of olfactory response further confirmed that male H. parallela was attracted with the selection efficiency of 93.3% when the volume ratio of  LIME  to (R)-(-)-linalool was 7∶1. So it can be deduced that the sex pheromone of Holotrichia parallela in Shandong province were the mixture of  LIME  and (R)-(-)-linalool with the ratio of 7∶1. The results may serve as basis for developing the techniques of sex pheromone attraction to control H. parallela.

Key words: Holotrichia parallela, sex pheromone, EAG, olfactory response, L-isoleucine methyl ester