The Dufour gland, which is relatively large in (female) bees of the genus Andrena (Fabr.) secretes a mixture of volatile substances. We have examined the composition of the secretion emanating from this gland in 6 species. The secretion is thought to function as a behaviour-releasing, olfactory signal. The present study has been undertaken as a first step towards eluci-dating its function. The volatile compounds have been isolated through solvent extraction and by direct pre-column technique, followed by gas chromatographic/mass spectrometric analysis, as well as capillary gas chromatography with a splitter-free intake system. Chromatographic and spectrometric data of the components of the secretions have been compared with those of reference compounds. Thin-layer chromatography and infrared spectroscopy have also been employed in the analyses. All trans-farnesyl hexanoate was found to be the dominant compound in five of the species. In two of these, geranyl hexanoate is a relatively large component. Besides, isomers of farnesene, geraniol, all-trans-farnesol and five other esters of these terpene alcohols have been found, together with a few straight chain, saturated hydrocarbons. In A. helvola geranyl octanoate was found to be the dominating compound with an appreciable amount of farnesyl octanoate. Geranyl hexanoate, geranyl octanoate and geranyl decanoate as well as farnesyl hexanoate and farnesyl octanoate have been prepared with the help of N,N'-carbonyldiimidazole. The isoprenoid esters were obtained in very good yields and high purity by this method. None of these compounds seem to have been found earlier in natural sources nor synthesized.
Bergström, Gunnar and Tengö, Jan, "Studies on Natural Odoriferous Compounds IX" (1974). Ba. Paper 117.
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