The influence of female moth/pheromone-trap competition in shaping temporal patterns of catches ofArgyrotaenia citranawas studied in a series of experiments conducted within a semienclosed courtyard on the campus of Oregon State University. Three distinct periods existed in relation to the catch of males in traps; the catch of males by caged female moths; and the estimated frequency of mating of females. In the first period, when male emergence precedes female emergence, few males were attracted to females, few females were mated, and the trap's catch efficiency was high. During the second period when emergence of males and females was more equal, the attraction of male moths to females increased and mating peaked. However, the pheromone trap's catch was similar or lower than during the first period. In the third period when male emergence was considerably less than female emergence, attraction of males to females and mating decreased sharply, while the trap's catch increased again and showed a small second peak. When high immigration rates of males were simulated results were similar, except that the second catch peak was much larger. Overall, competition between the pheromone trap and female moths appeared to be regulated by protandry and the cessation of calling by mated females, while mated males continued to respond to pheromone sources. Immigration and differential survivorship of males and females may account for the timing and magnitude of the second peak observed in the pheromone trap's catch.