The honeybee queen maintains her dominance over her workers by producing pheromones which inhibit oogenesis in workers. In bumblebees the level of social organization changes during the lifetime of a colony, which is started by a solitary queen who is able to dominate the firsts of her offspring, but who loses her dominance after some time when many workers start laying eggs. After the queen was forced by the "elite group" to leave the comb, one worker emerged and took the queen's position in the hierarchy. The dominance mechanisms in a bumblebee colony are intermediate between dominance based on purely agonistic behaviour and dominance completely through pheromones: the queen produces pheromones and additionally displays agonistic behaviour. In the honeybee queen both functions are ascribed to the 9-oxo-decenoic acid produced in her mandibular glands.