Control of pheromone production in the bark beetle, Ips cembrae

ABSTRACT. Exposure of newly emerged Ips cembrae adults to myrcene vapour resulted in the production of ipsenol and ipsdienol by males, in quantities comparable to those found during natural attack of larch trees. Treatment of male beetles with juvenile hormone analogue (JHA) triggered production of 3-mefhyl-3-buten-l-ol, the third component of the aggregation pheromone complex. The beetles are therefore capable of producing ipsenol and ipsdienol immediately upon contact with host resin, whereas methylbutenol production appears to be hormonally controlled upon the initiation of feeding. Beetles exposed to the enantiomers of ipsdienol apparently utilized only (R)-(—) ipsdienol to synthesize ipsenol, suggesting a high degree of chiral selectivity.