Regulation of queen number by workers in colonies of social insects.

Experiments with fire ants suggest that queen pheromones act quantitatively in the regulation of queen number in colonies of social insects. Specific mechanisms probably include recognition by workers of unique quantitative blends of pheromones produced by queens, and quantitative effects of pheromones acting at the level of the colony on workers and at the level of the individual on queens. Several aspects of this quantitative hypothesis of pheromone action were tested.