Production of verbenol pheromone by a bacterium isolated from bark beetles.

Abstract

THE aggregation pheromones of the bark beetle, Ips paraconfusus Lanier1 are expelled in the faecal pellets of male beetles feeding on the phloem of Pinus ponderosa2,3. These substances, cis-verbenol, ipsenol, and ipsdienol4, seem to originate in the hindgut5 but the precise site of their biosynthesis has not been determined. In various species of Ips a connection has been convincingly demonstrated between the production of these pheromones in the hindgut and either ingestion of phloem or exposure of the beetles to host plant oleoresin6. More specifically, exposure of individuals of certain species of Ips to myrcene can result in an increased production of ipsenol and ipsdienol7 and exposure of certain species of Dendroctonus to α–pinene results in an increased production of cis- and trans-verbenol8–10 in the hindgut. It seems therefore that a precursor–product relationship exists between certain host plant substances such as α-pinene and myrcene and the three aggregation pheromones mentioned above.