Invasive yellow-legged hornet establishes first nest in Poland, near Kraków

A nest in Wielka Wieś

A beekeeper found a fully developed nest of the yellow-legged hornet (Vespa velutina) in Wielka Wieś, near Kraków, which Super Express reports is the first such nest in Poland. Individual hornets were later also seen at the AGH University apiary in Kraków, but no nest has been found there so far. Two sites have been confirmed to date, and experts expect there are more.

The species was first recorded in Europe in 2004, when it was found in France. It spread over the following years to neighbouring countries, including Germany and the Czech Republic. Researchers had expected it to reach Poland from the Silesian Voivodeship, since the nearest previously documented site was in Opava on the Polish-Czech border, so the Małopolska find came as a surprise.

A threat to honeybees

Dr Łukasz Nicewicz of the University of Silesia in Katowice, who is working with a group of scientists and beekeepers on the case, says the hornet is especially dangerous to honeybees. It hunts right at the hive entrance, which can greatly restrict bee traffic in an apiary, and colonies can starve because foragers stop returning to a hive where food is stored.

Nicewicz also pointed to the season in which adults were observed. He said the timing worries him because of what happens next in the hornet's life cycle.

In autumn the queens mate and burrow into the ground, waiting there for spring when they start building their own nests.

Where the hornets came from

Scientists plan genetic tests on a dozen or so individuals to find out how the insects arrived. Nicewicz outlined two possibilities: either a new population spread from a place such as Germany, France or Slovenia, or the hornets were brought in accidentally, for example through transport. Super Express reports that experts are preparing to remove the nests together with beekeepers and are asking the public to report suspicious sightings, including through the iNaturalist app.

How to recognise it

The insect is about 2.5 centimetres long. Its thorax and most of its abdomen are black, and the last three segments of its legs are yellow. Only the tip of the abdomen carries a yellow-orange band, and the outermost leg segments are bright yellow. Nicewicz said the captured specimens measured about 2.5 cm.