Pheromone

A pheromone is a chemical messenger that acts between individuals rather than inside one body, as a hormone does. An animal releases it into the air, onto a surface or into water, and other members of the same species detect it by smell or taste, often in astonishingly small amounts. The word was coined in 1959, the year chemists identified bombykol, the sex attractant of the female silkworm moth, as the first known pheromone.

Insects rely on pheromones for much of their communication. Female moths release sex pheromones that males can follow from far downwind. Ants lay trail pheromones that lead nestmates to food, bees and ants release alarm pheromones when disturbed, and bark beetles give off aggregation pheromones that draw others to the same tree. In social insects, queen pheromones help keep the colony organized. Many mammals also use chemical signals, often sensed by the vomeronasal organ in the nose, to mark territory or advertise readiness to mate; whether humans have true pheromones is still unsettled.

Because pheromones are specific to one species and work in tiny doses, synthetic copies are used in farming to monitor pest numbers in traps and to confuse males so they cannot find mates, a method called mating disruption that cuts insecticide use.