(Z)-3-Hexenyl (R)-3-hydroxybutanoate: A male specific compound in three North American decorator wasps Eucerceris rubripes, E-conata and E-tricolor

The males of the decorator wasps Eucerceris have been observed to display a bdomen-dragging behavior on plants surrounding their nest. It is thought th at this applies a territorial-marking sex pheromone that serves to alert fe males to the males' territory for courtship and mating. The extracts of thr ee species E. rubripes, E. conata, and E. tricolor have been analyzed by GC MS. The gas chromatograms revealed the presence, in large quantities, of on e common volatile compound in the male head extracts, By analogy with the c losely related bee wolves Philanthus. we believe the pheromone is produced in the mandibular glands. Utilizing mass spectrometry, microreactions, FT-I R, and H-1 and C-13 NMR spectroscopy the structure of the pheromone was pro posed to be (Z)-3-hexenyl 3-hydroxybutanoate, which was confirmed by synthe sis. The absolute configuration of the chiral center was determined to be R for the three species by preparing the Mosher esters of the insect samples and comparing their GC retention times with a synthetic sample of known ab solute configuration. In addition 2- and 3-hexenoic acid and some aromatic compounds were also found in varying quantities in both males and females a long with hydrocarbons and fatty acids, although no species-specific profil es emerged.