Back to Science

Pheromone is a substance, secreated by an animal, that is detected by others of the same species and produces a response in them.

Pheromones are found throughout the living world and are probably the most ancient form of animal communication. Insects regularly use pheromones to attract others of its kind for reproduction.

Traps baited with synthetic pheromones are now used to capture many such pest species. The sexual pheromone of other undesirable insects are sometimes sprayed over an infested area so as to disorient males seeking females of their species. Insects also use pheromones in more complex ways.

Female Douglas fir beetles locate a host tree by its odor (A pinny scent peculiar to female douglas fir beetles), bore a hole, and then broadcast their sexual pheromone. Males fly upwind, find the females, shut off their production of pheromone with an acoustic signal, and than themselves produce an odor that blocks the receptors for douglas fir in other beetles. When a tree has collected a critical number of mated females, this inhibition odor makes the tree invisible to the beetles sense of smell and prevents the tree form be overly parasitized.

Social insects--insects that live together in groups--usually have a repertoire of pheromonal messages. Ant, for example, usually have a pheromone for marking trails to food, another for eliciting attacks on enemies they have discovered, a third that signals the need to flee, and yet others taht identify their larvae in the darkness of the nest. Several species of invertebrates have broken the elaborate code of ants; for example, assassin bugs lay false odor trails and eat the ants that follow them, and a variety of parasitic or symbiotic beetles, millipedes, and arachnids produce the pheromones typical of larval ants and manage thereby to live undisturbed inside and nests, often feasting on eggs and larvae.