The sex pheromone glands of calling females (five females) were removed during the first 2 h of the scotophase and extracted in 20 L of hexane (Merck Ltd, Darmstadt, Germany) contained within a liquid-nitrogen-cooled 0.5-mL conical vial (Wheaton, Millville, NJ, USA) for 5-10 min. After all glands had been excised, the vial and its contents were brought to room temperature, and the liquid phase was transferred to a 1.1-mL conical glass vial (Alltech, Deerfield, IL, USA) for storage in the -80°C freezer before analysis. Females were collected from two locations in Canterbury (Lincoln and Little River) and analyzed separately.