1Department of Biochemistry, MS 330, University of Nevada-Reno, Reno, NV 89557-0014, USA. 2Department of Entomology, University of Minnesota, St Paul, MN 55108-6125, USA.
Male pine engraver beetles, Ips pini, produce most if not all of their acyclic pheromone components de novo. Feeding induces both Juvenile Hormone (JH) and pheromone production in male I. pini. JH treatment of unfed male insects induces ipsdienol production to the same level as feeding. Ipsdienol is formed via the isoprenoid pathway, in which 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R) is a key regulated enzyme. Topical treatment of male I. pini with JH increases both HMG-R activity and transcript levels in a dose and time dependent manner. In situ hybridization techniques were used to localize the tissue involved in pheromone production. The data are consistent with pheromone production being regulated by the feeding induced production of JH, which in turn induces transcript level and enzyme activity of HMG-R and perhaps other enzymes in the isoprenoid pathway leading to ipsdienol production.