Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/1996
Publication Date: N/A
Interpretive Summary: Aggregation pheromones were partially identified for three species of Drosophila fruit flies found in Europe. An aggregation pheromone is a natural chemical blend produced by a male fly when it is at the suitable feeding/breeding site; the pheromone attracts other individuals of that species to the site and fly reproduction occurs. This research was part of a larger project to study how a species of parasitic wasp locates its hosts, which are the larvae of the Drosophila flies (which live within decomposing vegetable matter). It has been discovered that the wasps cannot locate the fly larvae directly but instead locate the adult flies by their pheromone odor; once the site of fly reproduction has been found by the wasps, they simply wait until the fly larvae hatch from their eggs an then parasitize them. Thus the wasps use an indirect means of locating the host larvae in which the next generation of wasps will develop. The major pheromone chemical identified in this research is one which the wasps are known to be able to detect, providing a chemical explanation for the observed wasp biology.
Technical Abstract: Aggregation pheromones of Drosophila immigrans, D. phalerata and D. subobscura were demonstrated by testing hexane extracts of the flies in a windtunnel bioassay. Extracts of adult males of all species attracted conspecific males and females. However, D. subobscura flies were attracted only when the extract was applied on food. GC-MS analysis identified (Z)-11-octadecenyl acetate (cVA) in the extracts of adult male D. immigrans and D. phalerata. Both species were attracted to synthetic cVA. Male and female D. subobscura produced 5,9-pentacosadiene, 5-pentacosene, 2-methylhexacosene and 5,9-heptacosadien and minor amounts of cVA. Neither cVA nor (Z)-5-tricosene were attractive to the flies in windtunnel tests.