Pheromonal and enzyme genetic characteristics of the Bombus lucorum species complex in northern Europe

Spatial and temporal distribution of the species in the Bombus lucorum species complex, B. lucorum (L.), B. cryptarum (Fabricius) and B. magnus Vogt, were studied in Finland. Morphological distinction between the species is not as clear as in Central Europe, but B. lucorum can be distinguished from the other two with the help of enzyme genetic markers. B. lucorum is the most common of the three species in most of Finland, and B. cryptarum is abundant in the southwestern coastal area and in northern Lapland. B. magnus was only rarely found among the spring queens in southwestern Finland, and its range possibly restricts to southern and central parts of Finland. A comparison of the chemical composition of the male labial glands and enzyme genotypes shows that males produce species-specific marking pheromones

Multicomponent Mandibular Gland Secretions in Three Species of Andrena Bees (Hym., Apoidea)

Bees of the species-rich genus Andrena (Hymenoptera, Apoidea) emit, when handled, a strong odour which is easily perceived by humans. As proved in the 11 species investigated so far, the compositions of the volatile multicomponent secretions are species specific [1 -3], while the odour bouquets of males and females strongly resemble each other

Linalool in Mandibular Gland Secretion of Colletes Bees (Hymenoptera: Apoidea)

Linalool was identified as the main component of the mandibular gland secretion in females and males of four species of Colletes bees, viz., C. cunicularius, C. daviesanus, C. impunctatus and C. succinctus. It was also shown to be the dominant volatile compound in the same gland in male C. floralis (the female of this species has not yet been investigated). Further, in another species, C. similis, linalool is present in the mandibular gland secretions of females and males, but the dominant volatile component in these secretions is geranial, together with neral. Females of the species C. fodiens seem to lack monoterpenes altogether; nonadecane is the dominant volatile compound of the cephalic secretion (based on analysis of a single individual). When linalool is put out in the area of nest aggregation of C. cunicularius, where the males are patrolling , a distinct increase in flight activity is noted. The function of linalool is discussed on the basis of field observations

Studies on Natural Odoriferous Compounds IX

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\u27-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