We test that male response to female-produced sex pheromone in a long-lived moth species, Caloptilia fraxinella (Ely), is plastic and depends on male physiological state. Experiments were conducted to examine how males that differed in physiological state responded to signals of varying quality and quantity produced by manipulating synthetic pheromone blends. Reproductively active males have a lower pheromone response threshold and exhibit an upper threshold as compared to males in reproductive diapause, which respond only to high pheromone doses with no upper threshold. The nature of pheromone response also varies depending on the male’s physiological state. Reproductively active males showed a more narrowly-tuned response than did males in diapause. Both behavioral and electrophysiological data will be presented.