A 2-year field study has demonstrated that volatile compounds produced by plants when they are attacked by herbivores act as defenses by attracting predators to the herbivores and increasing the reproduction of the plants.

Both the frequency of sesquiterpene-emitting individuals and the defense capacity of individual plants determine the consequences of sesquiterpene volatile emission for individuals and their neighbors in populations of the wild tobacco Nicotiana attenuata.

The ability of Manduca moths to recognize changes in the profile of volatile compounds released by plants being attacked by Manduca caterpillars allows them to lay their eggs on plants that are less likely to be attacked by insects and other predators, and to avoid competing against other caterpillars of the same species for resources.