Zimma B O, Ayasse M, Tengö J, Ibarra F, Schulz C, Francke W
Department of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2003 Oct;189(10):769-75. doi: 10.1007/s00359-003-0451-x. Epub 2003 Sep 3.
The bumblebee Bombus (Psithyrus) norvegicus Sp.-Schn. is an obligate social parasite of B. (Pyrobombus) hypnorum L. Behavioural observations indicated that nest-invading B. norvegicus females may use allomones to defend themselves against attacking host workers. However, so far no defensive chemicals used by social parasitic bumblebee females have been identified. We analysed volatile constituents of the cuticular lipid profile of B. norvegicus females. Furthermore, we performed electrophysiological studies and behavioural experiments in order to identify possible chemical weapons. Coupled gas chromatography-electroantennography showed 15 compounds to trigger responses in antennae of the host workers. Using gas chromatography-mass spectrometry, the main compound among the cuticular volatiles of B. norvegicus females was found to be dodecyl acetate. A corresponding mixture of synthetic volatiles as well as pure dodecyl acetate showed a strong repellent effect on starved host workers. B. norvegicus females use dodecyl acetate to repel attacking B. hypnorum workers during nest usurpation and subsequently during colony development. Dodecyl acetate is the first repellent allomone identified in bumblebees.
挪威拟熊蜂（Bombus (Psithyrus) norvegicus Sp.-Schn.）是催眠熊蜂（B. (Pyrobombus) hypnorum L.）的专性社会性寄生蜂。行为观察表明，入侵巢穴的挪威拟熊蜂雌蜂可能利用异种信息素保护自己免受寄主工蜂的攻击。然而，迄今为止，尚未鉴定出社会性寄生熊蜂雌蜂使用的防御性化学物质。我们分析了挪威拟熊蜂雌蜂表皮脂质谱中的挥发性成分。此外，我们进行了电生理研究和行为实验，以确定可能的化学武器。气相色谱-电触角图联用显示有15种化合物能引发寄主工蜂触角的反应。通过气相色谱-质谱联用，发现挪威拟熊蜂雌蜂表皮挥发物中的主要化合物是乙酸十二酯。相应的合成挥发物混合物以及纯乙酸十二酯对饥饿的寄主工蜂表现出强烈的驱避作用。在巢穴侵占期间以及随后的群体发育过程中，挪威拟熊蜂雌蜂利用乙酸十二酯击退攻击的催眠熊蜂工蜂。乙酸十二酯是在熊蜂中鉴定出的第一种驱避性异种信息素。
