Abstract: 【Aim】 Insect pheromones are the chemical molecules for communication between individuals of insects. To better understand their neurological mechanisms and make better application, it is important to study the effect of sex pheromone on the expression of olfactory genes. 【Methods】 The quantitative realtime PCR (qRT-PCR) was used to study the changes in the expression levels of olfactory genes abp, pbp and or  in  Spodoptera litura male moths after exposure to synthetic sex pheromone. A newly developed pheromone-based electronic counting system was adopted to monitor the population dynamics of S. litura by sex pheromone trapping. 【Results】 The expression of abp, pbp and or  showed circadian rhythm in the antennae of male moths of S. litura. The expression levels of abp, pbp and or  and their circadian rhythm were significantly affected by the exposure to synthetic sex pheromone (Z9, Z11-14:OAc+Z9, Z12-14:OAc). The population dynamics of S. litura male moths monitored by sex pheromone trapping also showed clear circadian rhythm. 【Conclusion】 The circadian rhythm of the gene expression was correlated with that of the male mating behavior. Our results provided the first evidence to elucidate the enhancement of peripheral and central neuronal sensitivity of olfactory system of S. litura moths stimulated by sex pheromone at the gene expression level by the exposure of pheromone compounds. These results would be helpful to our understanding of the molecular mechanisms of pheromone recognition, the application of insect pheromone by mating disruption and pest forecasting and control by mass trapping with sex pheromone.

Key words: Spodoptera litura , sex pheromone, pheromone binding protein, olfactory receptor, circadian rhythm, gene expression