Flies expressing desat1Scer\UAS.cWTa under the control of Scer\GAL41407 show a small but significant increase in unsaturated hydrocarbons at the expense of saturated hydrocarbons. In females, total diene and pheromone levels are particularly enhanced (by 23-28%), while in males the pheromone level is increased from 8-12%, depending on the line used.