On the functional significance of juvenile hormone in the accessory sex glands of male Heliothis virescens.

The storage of large quantities of juvenile hormone (JH) in male abdomens is a phenomenon known from some species of moths. Juvenile hormone, stored in male accessory sex glands (ASG), may be transferred to the female during copulation, but the physiological significance of the JH transfer remains unclear. Here, using the moth Heliothis virescens as a model, we show that JH transferred from male to the promiscuous female promotes JH synthesis and egg development in the female. We propose that this explains the functional significance of JH transfer in species that exhibit last male sperm precedence, and that this hormone acts as a bioactive substance which the first male to mate uses for co-opting and regulating the female's gonadotropic mechanisms, thereby ensuring that despite last male sperm precedence he will sire a significant number of viable offspring.