Two decades ago Europe had never faced Asian hornets on its shores. Today, scientists and farmers describe the species as a troubling invasion that has nests detected in a dozen European nations. In Spain, this invasive group expanded across more than twenty provinces over the past decade, especially in the northern part of the Iberian Peninsula. Experts warn that these hornets are efficient predators of other insects, capable of altering ecosystems and posing risks to people. But how did this spread begin?
All evidence points to a single initial introduction: a fertilized queen that landed in 2004 in Bordeaux, France, aboard a commercial ship from Asia. Once she reached solid ground, she began building a nest and laying eggs, allowing the population to grow rapidly. Since that event, Asian hornets have been observed across Europe, a pattern highlighted by a recent study from University College Cork in Ireland. The researchers argue that the first queen’s migration set the stage for the later spread.
genetic testing
The study, published in the Journal of Hymenoptera Research, offers a detailed genetic analysis of an Asian hornet found in Ireland. To date, only a single genetic copy has been detected in the country. Its discovery in April 2021 surprised the scientific community and raised questions about how such an insect arrived in the Irish capital. Consequently, the specimen was sent to the National Museum of Ireland for comprehensive genetic testing to determine its origin.
After sequencing the insect’s DNA and comparing it with other Asian hornets identified in Europe, researchers concluded that all copies found in Europe share a common lineage. They trace back to the original Vespa velutina that reached Bordeaux almost two decades ago. Simon Harrison, a leading scientist on the project, notes that this case illustrates how an invasive species can become a pest even with very limited genetic diversity.
same pedigree
This is not the first time the scientific community has pointed to the same Asian hornet as the source of the European invasion. While only a handful of genetic studies exist, the hornets belong to the same lineage. Earlier research had traced the origin using a single gene; the new study adds two more genes, strengthening the conclusion that European hornets share a common genetic background. Eileen Dillane, a project lead, emphasizes that this finding helps explain the uniform spread and persistence of the species across different regions.
Experts describe the situation as a mixed bag. On the one hand, the shared lineage offers a clearer target for management strategies. On the other hand, the invasion remains stubborn because a single fertile queen can reestablish a nest after destruction, enabling hundreds of hornets to reappear. The researchers suggest that eradication methods based on biological control hold promise, provided they are carefully designed to protect other species and ecosystem processes.
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In any case, the evidence underscores how quickly an isolated introduction can evolve into a continental-scale challenge. Regional authorities are urged to monitor nests, deploy targeted control measures, and coordinate cross-border responses to curb the spread of Vespa velutina across North America and Europe alike.
Note: no direct contact details are provided in this article and no external links are included. All findings are supported by institutions and researchers cited in the study at University College Cork, the National Museum of Ireland, and the Journal of Hymenoptera Research.