In 2004, Vespa velutina was first seen in
France. Since then, this fierce honey bee predator
spread across many countries, giving rise to one of the
most phenomenal insect invasions in Europe. An early
study in France showed a genetically depauperate
population, originating from a single multi-mated
queen introduced from China. Here, we further unveil
V. velutina invasion genetics in Europe by surveying
the Iberian and Italian peninsulas using cytonuclear
markers. Our results show that the French population
acted as the colonists’ source in Spain, Portugal and
Italy, leading to rejecting the hypothesis of multiple
introductions from the native range. While Spain and
Italy were colonized predominantly by leading-edge
expansions from the French core population, in
Portugal the invasion started from long-distance jump.
Both processes were accompanied by a significant
reduction in genetic diversity, with stronger losses for
Portugal (Ar = 17.4%; uHe = 42.3%) than for Spain
(Ar = 9.0%; uHe = 20.6%) or Italy (Ar = 16.3%;
uHe = 26.8%). Signatures of differentiation and population
structure, associated to the founding event in
Portugal, enabled detection of secondary contact
between the front derived from the primary propagule
introduced in France and the front derived from the
secondary propagule introduced in Portugal. Detection
of first-generation migrants in the three countries
suggests continuous gene flow that is bringing in new
alleles, and this effect is stronger in Portugal, as
reflected by a 20.3% increase in allelic richness.
Overall, this study provides further insights into the
invasion genetics of V. velutina in Europe, which can aid developing strategies to manage this major threat
to beekeeping.
This research was funded by the program POSEUR-
03-2215-FC-000008, through the project ‘‘GesVespa:
Estratégias de gestão sustentável da Vespa velutina no Norte
de Portugal’’. Fundação para a Ciência e a Tecnologia provided
financial support by national funds (FCT/MCTES) to CIMO
(UIDB/00690/2020).
