Sex pheromone biosynthesis in the red-banded leafroller moth, studied by mass-labeling with stable isotopes and analysis with mass spectrometry.

A technique for mass-labeling was developed to study sex pheromone biosynthesis in the red-banded leafroller moth,Argyrotaenia velutinana. With this technique, the pheromone components and all fatty acyl groups in the pheromone gland were analyzed for incorporation of label in the same analytic ran with gas chromatography-mass spectrometry, using chemical ionization and selected ion monitoring (GC-SIM-CI-MS). Sex pheromone glands were incubated with fatty acids or triacylglycerols labeled with at least three deuterium atoms or carbon-13 atoms. The results of these incubations support an interpretation in which hexadecanoate is chain shortened to tetradecanoate, which is desaturated to produce (E)- and (Z)-11-tetradecenoate precursors for the sex pheromone components (E)- and (Z)-11-tetradecen-1-yl acetate. Labeled (E)- and (Z)-11-tetradecenoyl groups in synthetic triacylglycerols were not incorporated into the sex pheromone components, perhaps indicating that this lipid class is not a donor of the immediate fatty acyl precursors in sex pheromone biosynthesis.