Production of Pheromone Components, Chalcogran and Methyl (e, 2)-2,4-decadienoate, in the Spruce Engraver Pityogenes Chalcographus

4apillary gas chromatography and mass spectrometry were used to quantify the amounts of Eand Zchalcogran and methyl (E,Z)-2,4-decadienoate (E,Z-MD), pheromone synergists of the bark beetle Pitygenes chalcographus (Coleoptera: Scolytidae). Males were exposed or not to vapours of host (Norway spruce, Picea abies) oleoresin or allowed to feed in host logs prior to extraction of body parts and hindguts for pheromone synergists. E,Z-MD and chalcogran were produced sex-specifically in males, and only after feeding on host-plant tissue. The pheromone synergists were not produced during exposure to oleoresin vapours. Several oxygenated monoterpenes (including trans-verbenol, myrtenol, and transmyrtanol) were found in feeding males. The amounts of the pheromone synergists in unmated feeding males remained relatively constant over a 3.5 day period. In contrast to many other pheromone components of bark beetles, including chalcogran, E,Z-MD was found primarily in the male's body (head and thorax) with less in the hindgut (abdomen). The probable acetogenic origins of both pheromone components indicate that the species has evolved control over production and is thus not dependent on host precursors as expected in many other bark beetles. Key Word Index: Pheromone; Pityogenes chalcographus; Coleoptera; Scolytidae; methyl (E,Z)-2,Cdecadienoate; chalcogran; Picea abies; synergist; sex-specific