Alarm pheromones are major communication signals in animals and major semiochemicalsin the colony organisation of social insects. We investigated the composition ofvenom in Vespa velutina, an invasive hornet species accidentally introduced into Europe adecade ago. Crushed venom glands were applied to seven wild V. velutina nests and inducedaggressive responses of workers in all the colonies tested. Then, solvent extracts or headspaceSolid Phase Micro Extraction (SPME) were analysed and quantified by gas chromatographycoupled with either flame ionization detector or a mass spectrometer, and checked retentiontimes to Kovats indices and Linear retention indices (LRI). We compared our results to thoseobtained in the same species from its native area in a previous study. Nonan-2-one and the 4,8-dimethylnon-7-en-2-one were found in large amount in the venom gland. Five other moleculesincluding the heptan-2-one, non-8-en-2-one, undecan-2-one and two unknown moleculeswere also found. Similar compounds were globally found, however, one unknown compoundwas present in our European population but absent in native area ones and should be identify.Although pheromones are thought to be species-specific, our results suggest that their compositionmay vary within species due to population history, thus questioning its value as a taxonomictool. Although our results are preliminary, we also recommend carefully considering theorigin of the Vespa velutina individuals chosen to develop pheromone-based methods (attractantsor mating disruption) for pest management.< Réduire