Kairomone

A kairomone is a chemical substance produced and released by a living organism that benefits the receiver and disadvantages the donor. The kairomone improves the fitness of the recipient and in this respect differs from an allomone. An example of this can be found in the Ponderosa Pine tree (Pinus ponderosa), which produces a terpene called myrcene when it is damaged by the Western pine beetle. Instead of deterring the insect, it acts as a synergist with aggregation pheromones which in turn act to lure more beetles to the tree. The term is mostly used in the field of entomology.