Fig. 8

Postulated biosynthetic steps to account for the typical pheromone components found in the Tortricidae. Fatty acid biosynthetic routes for sex pheromone components of Tortricinae (a) and Olethreutinae (b) are illustrated. Starting from palmitic acyl (C₁₆), the pheromone precursors are produced via a combination of chain-shortening (by limited beta-oxidation) and desaturation steps. Genes encoding the fatty acyl desaturases with the postulated activities have been characterized in this study or previously, with the exception of the enzyme(s) involved in the synthesis of ∆8 monoenes in Olethreutinae