The phenomenon whereby an animal shows different forms of behaviour at different ages. It is best known in colonies of social insects, where certain members of the colony may perform different tasks as they get older. For example, worker honeybees generally perform duties within the hive (such as brood care) up to the age of about 2–3 weeks and then switch to foraging outside the hive for nectar and pollen for the remaining weeks of their lives. The switch is controlled by social cues within the hive, such as pheromones, and is associated with an array of genetic, metabolic, and physiological changes in the insect.