Pheromone

n. chemical substance produced in the body that excites a response in the opposite sex

A pheromone is a chemical that triggers a natural behavioral response in another member of the same species. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Their use among insects has been particularly well documented, although many vertebrates and plants also communicate using pheromones.
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Pheromone /pher·o·mone/ a substance secreted to the outside of the body and perceived by other individuals of the same species, releasing specific [more]Pheromone - Community and Resources

Noun
1. a chemical substance secreted externally by some animals (especially insects) that influences the physiology or behavior of other animals of the same species
(hypernym) secretion

n. pheromone, chemical substance produced in the body that excites a response in the opposite sex