Figure 6.

Proposed pheromone biosynthetic pathways for the European corn borer and Asian corn borer. The male and female pheromone components in the European corn borer (ECB) and the Asian corn borer (ACB) are biosynthesised de novo from the ubiquitous palmitic acid (16:Acid). The routes leading to the 14-carbon acetate components produced by females and to the 16-carbon acetate components used by males employ common key desaturation enzymes. The Δ14-desaturase appears to be common to female ACB and male ECB pathways, as well as the Δ11-desaturase that is shared in male and female ECB pathways. Note that the Δ9-desaturation leading to palmitoleic acid (Z9-16:Acid) also occurs in females of both species, but the reduction and acetylation of this substrate occur in males only. Pathways for male compounds postulated from the analysis of precursors and for female compounds adapted from [40] and references therein.