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Abstract  Females of the European beewolf, Philanthus triangulum, possess a large glove-shaped gland in the head, the postpharyngeal gland (PPG). They apply the content of the PPG to their prey, paralyzed honeybees, where it delays fungal infestation. Here, we describe the chemical composition of the gland by using combined GC-MS, GC-FTIR, and derivatization. The PPG of beewolves contains mainly long-chain unsaturated hydrocarbons (C23–C33), lower amounts of saturated hydrocarbons (C14–C33), and minor amounts of methyl-branched hydrocarbons (C17–C31). Additionally, the hexane-soluble gland content is comprised of small amounts of an unsaturated C25 alcohol, an unknown sesquiterpene, an octadecenylmethylester, and several long-chain saturated (C25, C27) and unsaturated (C23–C27) ketones, some of which have not yet been reported as natural products. Surprisingly, we found a dimorphism with regard to the major component of the PPG with some females having (Z)-9-pentacosene, whereas others have (Z)-9-heptacosene as their predominant component. The biological relevance of the compounds for the prevention of fungal growth on the prey and the significance of the chemical dimorphism are discussed. [ABSTRACT FROM AUTHOR]

Abstract??Ground-nesting animals share their habitat with countless microorganisms that can play important roles as pathogens or competitors for food resources. Thus, species that store food in the soil, either for themselves or for their progeny, must protect these resources against microbial degradation. Females of the European beewolf,Philanthus triangulum, hunt honeybees as provisions for their brood and store the paralyzed prey in their subterranean nests. A previous study had shown that females lick the surface of prey before oviposition and that this licking treatment delays mold growth. Here, we showed that females apply large amounts of a secretion from their postpharyngeal glands onto the surface of their prey during the licking behavior. Inhibition-zone assays showed that comparatively large amounts of the gland secretion had no direct antimycotic effect. We discuss our findings with regard to other possible mechanisms of the postpharyngeal gland secretion against fungal growth. [ABSTRACT FROM AUTHOR]

The chemical composition and functional significance of pheromones of solitary Hymenoptera is much less well known compared to social species. Males of the genus Philanthus (Sphecidae) are territorial and scent mark their territories to attract females. Because of inconsistent results of earlier studies, we reanalyzed the content of the cephalic glands of male European bee- wolves, Philanthus triangulum F. Besides a variety of alkanes and alkenes, four major compounds were found. Two of these, (Z)-11-eicosen-1-oI and (Z)-10- nonadecen-2-one, had been previously described as constituents of the cephalic glands. We identified 1-octadecanol as a new component of the cephalic gland, and a fourth compound, enantiopure (S)-2,3-dihydrofarnesoic acid, was identified for the first time in nature. Structural elucidation and enantiomeric analysis were performed by HRGC-MS and HRGC-FTLR as well as enantioselective gas chromatography and by means of authentic reference compounds. Occurrence and function of the four compounds in insect chemistry are discussed. [ABSTRACT FROM AUTHOR]