Endogenous suppression of pheromone production in virgin female moths

Sexual receptivity generally is reduced in moths after mating. We found that even in virgin Heliothis zea females the titer of pheromone declines after the third night of adult life, although the number of eggs laid increases. Reduction in pheromone titer is not due to reduced amounts of 'pheromone biosynthesis activating neuropeptide'. We have discovered that a substance present in the bursa, ovaries and hemolymph of senescing virgins suppresses pheromone production. A similar factor was found in 2-day-old mated females indicating that both virgin and mated females use this factor to suppress pheromone production.