A chemical substance or a blend of substances, usually a glandular secretion, which is used in communication within a species: One individual releases a pheromone as a signal and another responds after tasting or smelling it.

Primer pheromones alter the physiology of individuals and prepare them for new behavioral repertories. Releaser pheromones evoke responses directly.

A chemical substance exchanged among members of the same species that induces a state of alertness or alarm in the face of a common threat: Jeff read about thealarm pheromone referring to the release or ejection of a certain substance to alert the others of the same species of an oncoming danger, threat, or attack.

A pheromone with an active space restricted so close to the body of the sending organism that direct contact, or something approaching it, must be made with the body in order to perceive the pheromone; A surface pheromone with a chemical secretion, can attract a member of the opposite sex only by the means of the outside part or surface of the sending organism.

A substance deposited on or around the nest that is specific to a colony or species: Territorial pheromones aids in the exclusion of alien colonies.

A substance laid down in the form of a trail by one animal: A trail pheromone is important so that another member of the same species.can follow the path successfully.