Effect of tyramine (TA) and octopamine (OA) on insect behaviour such as sex-pheromone production, egg laying and metamorphosis is discussed in detail. TA inhibits pheromone production in vitro in a dose dependent manner and dopamine (DA) has a lower inhibitory activity than TA, whereas OA has no effect, suggesting that TA is a candidate for regulating pheromone production in the pheromone gland of Bombyx mori, although other factors could be responsible for the pheromonostatic function. The inhibition of progeny formation in Drosophila melanogaster could be due to inhibition of...