Figure 1. Simplified biosynthetic pathway of the Heliothis subflexa sex pheromone, modified from (Groot et al., 2009b) with permission. Desaturation and β-oxidation produce mono-unsaturated acyl-CoA precursors from 18 or 16 carbon acyl CoA derivatives, which are then modified to form acetate esters, alcohols, and aldehydes through specific enzymatic conversions. The ∆9 and ∆11 desaturases create a double bond between the 9th and 10th or 11th and 12th carbon of the 18- or 16-carbon acyl-CoA derivatives, respectively. β-oxidation shortens the chain length from 18 to 16 carbons. Note that (Z)9-16 acyl-CoA can be formed through two alternative routes. The compounds present in the pheromone glands of H. subflexa are in grey boxes.