Abstract: Mating experience could not affect the production of sex pheromone in the female glands 24 h later, which meant that the beet armyworm females might call and mate again in next scotophase. This result explained the phenomenon why the beet armyworm could mate several times in their life under field conditions. On the contrary, ambient temperature greatly influenced the pheromone biosynthesis in the beet armyworm females. The optimal temperature for the biosynthesis of sex pheromone was between 15～25 ℃. Under the temperature beyond this range,the biosynthesis of the pheromone components was disturbed in terms of absolute titers,proportions,and their CVs. The biosynthesis of component Bwas suppressed under 35 ℃,and the proportion of Ato Bwas significantly higher. In contrast,under 10 ℃,the titer of Aand the proportions of Ato Bwere disturbed significantly,and the proportions of Ain ABand ADbinary blends changed significantly. Furthermore,the CVs of the ratios of Ato Band Ato Dbecame larger than10 % under 10 ℃.

Key words: Mating, Temperature, Spodoptera exigua, Sex pheromone