A single Asian hornet sparked the species' fast and ongoing spread across Europe, researchers discovered. Scientists have revealed that all Asian hornets living in Europe likely descended from a single mated queen that landed in France in 2004.
The Asian hornet, or V. velutina, is thought to have arrived in Europe from China in 2004, and since then it has spread rapidly across the continent. The Asian hornets in Europe are all descendants of a single pedigree.
Discovering the genetic lineage of this hornet is evidence that single mated queens can rapidly re-colonise areas where hornets have been eradicated, such as by intensively destroying all nests in a location. It also shows alien insects could become invasive pests after just one gets accidentally imported.
However, finding that each Asian hornet in Europe is closely related could mean they could be eradicated by biological control. Dr Simon Harrison, who is part of the research team, said: “Our research has revealed the remarkable potential for population expansion of social insects in invaded areas, even when original genetic diversity is extremely low.”
In Europe the Asian or “Yellow-legged” hornet is a predator to honeybees, hoverflies and other wasps, and poses a serious risk to beekeeping, biodiversity and pollination services. The insect can measure up to 4cm in length and is capable of delivering a painful sting, but it is not aggressive by nature.
Currently, it remains controlled in Britiain but it is well established across mainland Europe and the Channel Islands. The research published in Journal of Hymenoptera began in April 2021, when the Irish National Parks and Wildlife Service confirmed one Asian hornet was found “alive but dying” in a private home in Dublin - marking the first Irish record of the species.
The specimen was deposited in the National Museum of Ireland. Scientists from the School of Biological Earth and Environmental Sciences (BEES), University College Cork, and partners at the EU Atlantic Positive Project began investigating whether the new hornet came from Europe, or was a new invasion from its native range in Southeast Asia.
Genetic analysis was performed and data was compared with specimens discovered in locations across Europe. Dr Eileen Dillane of BEES said: “Earlier work had demonstrated that Asian hornets in Europe apparently shared the same genetic lineage, based on studies of a single gene.
“We took this a step further and looked at two additional genes which would be more sensitive in detecting variation within the invasive population. Data from all three genetic markers confirmed that not only are Asian hornets in Europe of a single pedigree, but are likely descended from a single mated queen hornet that somehow arrived in France in 2004. Furthermore, this lineage has not yet been described within the native range."
Researchers insist it is unlikely this is the beginning of a large-scale Irish invasion because Asian hornets do not thrive in the climate and habitat of Ireland. The black and yellow beasts need higher summer temperatures and a larger supply of energy-rich food. However, the authors advised: “Nonetheless, climate change is likely to increase the threat of a successful invasion in the future, so vigilance against this species must be maintained.”
