SEX-PHEROMONE OF GLOSSINA TACHINOIDES - ISOLATION, IDENTIFICATION, AND SYNTHESIS

Study of lipids from male and female laboratory-reared flies led to th e demonstration of a potent contact sex stimulant in extracts and cuti cular hydrocarbons of the female tsetse fly Glossina tachinoides (West wood) against conspecific males. Thin-layer and column chromatography indicated that extracts contained hydrocarbons and saponifiable lipids . Biological activity was found in the alkanes from females, including prominent branched-chain alkanes that were detected by gas chromatogr aphy (GC). The alkanes were separated and collected by preparative gas chromatography (GC), and only the 37-carbon region showed biological activity. GC-mass spectrometry showed the major peak contained a mixtu re of isomeric 11,23-, 13,25- plus a minor amount of 11,21-dimethylhep tatriacontane. Two racemic isomers were synthesized, and bioassays sho wed that the greatest activity was possessed by the 11,23- isomer with somewhat less activity in 13,25-dimethyl heptatriacontane. Dose-respo nse data showed ED50 at 5 mu g per decoy with solvent-washed males, no nspecific females, or corks as decoys. These alkanes released sexual a ctivity in males that comprised most of the behaviors released by a fe male By of the same species.