A member of the reproductive caste in semi-social or eusocial species.

The existence of the queen caste presupposes the existence also of a worker caste at some stage of the colony life cycle.

Queens may, or may not, be morphologically different from workers.

The inhibitory influence of the queen on the reproductive activities of the workers and other queens.

Originally, the set of pheromones by which the queen continuously attracts and controls the reproductive activities of the workers.