For several years, specialists have been watching with concern the expansion of the Asian hornet in Europe, which is particularly dangerous for honey bees and biodiversity. The occurrence of these insects has been confirmed in Spain, Belgium and Northern Ireland, among others. Based on genetic analyses, Irish scientists have determined that the European hornet invasion was initiated by a single queen that appeared in France 18 years ago. According to the researchers, their findings are both good and bad news.
Asian hornet (Vespa velutina) naturally occurs in China, India and Southeast Asia. At the beginning of the 21st century, however, its expansion to other regions of Asia, and finally to Europe, began to be observed. It appeared on our continent around 2004, probably along with the transport of porcelain. Its occurrence has already been confirmed in Spain, Italy, France, Portugal and Belgium, among others. In April last year, it was confirmed that it had also reached Ireland. A single specimen, now dying, was found in a private flat in Dublin, the first Irish record of the species’ presence.
The circumstances in which the hornet came to this area are not known. Meanwhile, scientists emphasize that gaining this knowledge is important. ‘We are particularly interested in determining whether the first individual was already from Europe or from its native South-East Asia, as the latter would indicate a potential new source of invasion,’ write Irish researchers from the University of Cork in the Journal of Hymenoptera Research”.
“We’ve gone one step further”
The specimen found in a Dublin apartment was deposited at the National Museum of Ireland and identified by Dr Aidan O’Hanlon. The scientist suggested conducting a genetic analysis to determine the origin of the hornet. In collaboration with biologists at University College Cork, he then compared the genetic data with samples collected at several other locations.
‘Previous work suggested that all Asian hornets in Europe share the same genetic lineage, but this conclusion was based on a single gene study,’ explained co-author Dr Eileen Dillane. “We went a step further and looked at two additional genes that are much more sensitive to detect variation in the invasive population,” he explains.
Analysis of all three genes confirmed that Asian hornets in Europe not only share a common lineage, but are likely descended from a single queen that somehow reached France in 2004. As the authors point out, “our study confirmed the extraordinary invasive potential of this species on infested areas”.
Good and bad news
According to the researchers, their findings are both good and bad news when it comes to combating the Asian hornet in Europe.
Bad because, according to the results obtained, solitary hornet queens can quickly and easily recolonize areas from which they were previously exterminated (for example, after destroying all nests in a given area). Good, because such close kinship of all individuals gives hope for the development of effective control methods based on biological control.
Scientists: Climate change could cause expansion
As the researchers conclude, ‘at this point in time, in an Irish context, it is unlikely to be the beginning of a larger-scale invasion.’
“The climate and habitat landscape of Ireland do not seem to be optimal for the development of this species. The Asian hornet requires higher temperatures in the summer and access to more nutritious food. Nevertheless, due to the ongoing climate change, the expansion of the hornet will probably become a fact in the near future. Therefore, we should be very vigilant towards this species.”
Asian hornets. Where do they come from
Experts report that the Asian hornet is not aggressive towards humans, but shows a lot of aggression towards other insects. In the areas it occupies, it eliminates honey bees, wasps and hoverflies. It is a huge threat to beekeeping and biodiversity.
One of the Asian hornets is a species with a scientific name Vespa mandarin. It is the largest hornet in the world, sometimes referred to as the “killer hornet”. It comes from East Asia and is widespread in countries such as India, Laos, China, Japan, and can also be found in some parts of Russia. In 2019, the presence of these hornets was also discovered in North America. They were probably there on a container ship moored in one of Washington’s ports.
These insects pose a great threat to bees. They attack the hives by luring other bees with pheromones and quickly killing the workers to get to the tasty bee larvae and honey. A small group of hornets is capable of killing an entire honey bee swarm in a matter of hours. They attack people if they feel provoked or threatened. The sting of this species is longer than that of bees and wasps, and their venom is more toxic. This year, this hornet species has received a new name.
PAP, tvnmeteo.pl, ncipmc.org
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