Aggregation pheromone characterization and comparison inDrosophila ananassae andDrosophila bipectinata

Abstract

(Z)-11-Octadecenyl acetate (Z11–18∶Ac) and (Z)-11-eicosenyl acetate (Z11–20∶Ac) were identified as the aggregation pheromones ofDrosophila ananassae, andZ11–20∶Ac was identified as the aggregation pheromone ofDrosophila bipectinata. Z11–18∶Ac andZ11–20∶Ac were not attractive alone; however, in combination with fermenting food odors, the acetates attracted flies of both sexes in a wind-tunnel olfactometer. The pheromones were present in the ejaculatory bulb of sexually mature male flies and transferred to the female during mating. MaleD. bipectinata released little if anyZ11–20∶Ac to the food; however, recently mated females releasedZ11–20∶Ac to the surrounding surfaces in just a few hours after mating.D. ananassae males, on the other hand, appeared to release moreZ11–18∶Ac andZ11–20∶Ac to the surroundings than mated females. AlthoughD. bipectinata males had noZ11–18∶Ac, flies were as attracted toZ11–18∶Ac as to an equal quantity ofZ11–20∶Ac.D. ananassae were attracted toZ11–18∶Ac but not toZ11–16∶Ac orZ11–20∶Ac. However,Z11–20∶Ac in combination withZ11–18∶Ac was significantly more attractive thanZ11–18∶Ac alone.