AbstractMated females of the tropical warehouse moth,Ephestia cautella, start laying eggs shortly after adult emergence. All eggs are laid within 4 days and the adult's total life span is 5 to 6 days. If mating is prevented, egg laying is drastically delayed and the life span is extended to approximately 10 to 11 days. Virgin females lay fewer eggs than mated insects. If the juvenile hormone analogue methoprene is applied topically (100 ng/pupa) 2 to 3 days prior to adult emergence, the number of eggs per virgin female increases and the life span is reduced, as compared with nontreated virgins, and reaches values similar to control (mated) females. Changs in the ecdysteroid titer of females are related to egg laying. The concentrations increase and reach a maximum before most of the eggs are laid. Accordingly, the peak maximum is delayed in virgins as compared with mated females. This delay is prevented after application of methoprene. Mated and virgin females have lower ecdysteroid levels than treated virgins. In contrast to mated females, males have much lower ecdysteroid levels throughout their adult life.