Unsaturated cuticular hydrocarbons serve as pheromones in insects. In D. melanogaster, these hydrocarbons are sexually dimorphic in both their occurrence and their effects. 7(Z),11(Z)-Nonacosadiene is a cuticular pheromone in female fruit flies that stimulates male courtship behavior. The biosynthesis of this C29 diene appears to be mediated by an elongase with female-based expression.
Unsaturated, long-chain hydrocarbons are found on the cuticles of insects and can act as pheromones. In mature Drosophila melanogaster, certain cuticular hydrocarbons are sexually dimorphic: males synthesize 23- and 25-C monoenes and females produce 27- and 29-C dienes. Each of these lipids plays specific roles in regulating male sexual behavior, with dienes stimulating courtship. 7(Z),11(Z)-Pentacosadiene is a 25-C hydrocarbon that is found in low abundance on cuticles of mature Drosophila females. Depletion of a female-specific elongase (eloF), which leads to an increase in 7(Z),11(Z)-pentacosadiene along with a parallel decrease in 7,11-nonacosadiene, significantly reduces copulation in Drosophila. This raises the possibility that 7(Z),11(Z)-pentacosadiene may act as an anti-aphrodisiac.