Essential oil components as pheromones. A review

Studies regarding pheromes consisting of essential oil components of various plants and released by insects and arachnids (pests) were compiled for this review. For example, verbenol and verbenone were found to be an essential part of the bark beetle's aggregation pheromone, released with the intent to round up its conspecifics. Concerning plant lice, aphids use (E)-beta-farnesene as an alarm pheromone. Furthermore, nepetalactol and nepetalactone, two essential oil components of the cat mint (Lamiaceae), occur as an aphid-released sex pheromone, emitted to induce mating behaviour. On the other hand, some bees imitate a linalool-containing orchid odour as their sex pheromone and thus attract their mating partners. The sand fly, responsible for the American visceral leishmaniasis, uses derivatives of either alpha-himachalene, germacrene D or cembrene as a sex pheromone. Studies about termites reveal a large amount of different presumable pheromone compounds that also appear as essential oil components, e. g. neocembrene as a part of the trail pheromone, (E,E)-alpha-farnesene as an alarm pheromone and other terpenes, such as for example. gamma-cadinene as primer pheromone, enforcing the effect of the juvenile hormone and therefore determining about caste development. Concerning the pest insects, management strategies, conducted with pheromone traps, are presented or compared. Regarding arachnids, studies about spider pheromones are rare, whereas more information is available about mites, which release neral and geranial as an alarm pheromone. Copyright (C) 2011 John Wiley & Sons, Ltd.