Production of Early Diploid Males by European Colonies of the Invasive Hornet Vespa velutina nigrithorax
Résumé
The invasive yellow-legged hornet Vespa velutina nigrithorax was accidentally introduced in
Europe in the early 2000s. As is the case in colonies of other wasp and hornet species, V.
velutina colonies are known to produce sexuals (males and new queens) at the end of the
summer. We show that early-stage colonies in French populations frequently produce
males well before the usual reproductive period. The vast majority of the males produced
are diploid, which is consistent with the loss of genetic diversity previously reported in introduced
populations in France. Since males do not participate in colony activities, the production
of early diploid males at the expense of workers is expected to hamper colony growth
and, ultimately, decrease the expansion of the species in its invasive range in Europe.