Like many other life forms, insects use chemical signals called pheromones to communicate alarm, to share information on location of food sources, and to attract the opposite sex. Understanding the role of pheromones in defense against predators, mate identification, and overcoming host resistance by mass attack allows us to develop control measures with low environmental impact.
Pheromones are also used to find out where pests are and how far they have spread. If pheromones are available, they provide a useful tool for detecting and delineating new infestations of invasive insects, such as long-horned beetles.
Bark beetles use attractant pheromones to summon others to help overcome the defenses of the host tree. Their attractant pheromones can be used to monitor population development. Anti-aggregants such as Verbenone are sometimes used to protect high value trees, such as those in campgrounds.
Lepidoptera are also good candidates for the use of pheromones. For example, pheromone traps identify new infestation spots at the leading edge of gypsy moth's inexorable spread, and by applying pesticides only to new outlying infestations, Forest Service scientists have shown we can slow the spread of gypsy moth by about 50%.