Mate-finding communication in many moths is mediated by the sex pheromones produced by females.Since differentiation of sex pheromones is often associated with speciation,it is intriguing to know how the changes in female sex pheromone have been tracked by the pheromone recognition system of the males.Moths of the genus Ostrinia, which show distinct differentiation in female sex pheromones, are good materials for studying the evolution of pheromone communication system.To detect the sex pheromones emitted by the conspecifie females, males should have a system that can discriminate pheromone components and their ratios.In this system, odorant receptors (ORs) in the olfactory sensilla of male moths should play an important role in the specific recognition of pheromone molecules.We cloned seven OR genes (OscaOR1, OscaOR3-8) and an Or83b homologue (OscaOR2), which is essential for the function of ORs, from the antennae of male Ostrinia moths.The results of functional assay of these ORs to pheromone components utilized in the genus Ostrinia will be reported.The response patterns will be discussed in terms of the evolution of sex pheromone production system in this genus.