A pheromone, trans-9-keto-2-decenoic acid, that is secreted by the mandibular salivary glands of a queen honeybee and inhibits the development of ovaries in the worker bees in the colony. The queen substance also affects the behaviour of the workers, preventing them from maintaining special brood cells for larvae that develop into new queens, and is a sexual attractant for drones during the queen’s mating flights. As the queen ages, the secretion of queen substance diminishes: the workers then construct brood cells for future queens, which they feed exclusively with royal jelly.