Will concupiscence be the tomb of the Asian hornet? The idea of trapping the males of this invasive species by attracting them using the sex pheromones produced by the females is gaining ground. A Franco-Chinese study published on February 7 in General Entomology thus suggests that a new molecular cocktail would be more effective in luring the male representatives of Vespa velutina.
Since its first detection in France in 2005, the hymenoptera has colonized Europe. Voracious, it attacks wild pollinators, but also wreaks havoc in the ranks ofApis mellifera, the honey bee – when it does not sting, sometimes fatally, humans. Beekeepers try to deal with the intruder with various traps and baits, but these lack efficiency and specificity: out of 100 insects trapped, it is estimated that 95 are not Asian hornets.
Eric Darrouzet (CNRS, University of Tours) and his Chinese colleagues have therefore embarked on the trail of sex pheromones specific to this species, produced by breeding females to attract males. In 2017, two promising molecules had already been identified, following taking samples from glands located between the sternites, the plates that divide the abdomen. In the present study, a third compound, produced in smaller quantities by the animal, was detected using a conventional method of gas phase chromatography coupled with a mass spectrometer.
The team then tested the effectiveness of several combinations representing various proportions of these three molecules, and identified the most effective during tests in nature, in France as in China, with slightly different populations of the insect. The mixture was placed on a blotter near a dead hornet which acted as a kind of “caller”, as in duck hunting. The study shows that the pheromone effect is maximal with one molecule more than the two previously identified. “And it is the mixture of the three, with a precise ratio, which makes it possible to attract males”summarizes Eric Darrouzet.
Aim for the founding queen of a nest
It now remains to take advantage of this attraction. The molecules, which are easy to reproduce chemically, cannot be patented, but the researcher has been contacted by a company, with which a partnership will be set up “to carry out new tests and develop the trap”. “She will then market it”he says.
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