a) When Ponderosa Pine tree (Pinus ponderosa) is attacked by the Western pine beetle, it produces a terpene called myrcene. It acts synergistically with aggregation pheromones and lure more beetles to the tree. This is in contrast with the allomones which serve as feeding deterrents.
The kairomones serve as attractants, arrestants and oviposition or feeding stimulants. These are used to attract natural enemies and predators for the insect pests.
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