Asian hornet in Luxembourg: nests and reporting

An operation followed by RTL shows how a nest is dealt with in practice. An established species, identification and reports: useful points for understanding the response in Luxembourg.

In the Grund, near the Pétrusse, a team from the Luxembourg City security service removed an Asian hornet nest in an operation followed by RTL. The operation illustrates a change in scale: the issue is no longer simply spotting a new species, but managing nests in a country where it is now established.

Carole Krier, from the security service, explains in the report that the aim is to contain its spread. The presence of a nest calls for a targeted response, depending on its surroundings and the risk to people. By itself, it does not make it possible to gauge the overall hornet population.

A professional operation, prepared for the morning cold

The team intervened early, with protective equipment and a device suited to the height of the nest. According to Carole Krier, temperatures close to three degrees made the insects less active than in warm weather. This observation describes the conditions chosen by the professionals; it does not make approaching the nest safe for a member of the public.

RTL reports that a pole connected to a steam device was used before the nest was removed. Preparation, protection for those carrying out the work and proper handling of the equipment are all part of the operation. Reproducing one element in isolation, using hot water or an improvised tool, would not replicate these safety measures.

The nest’s external size does not provide a count of its occupants. Carole Krier mentions the possibility of around two thousand hornets being in a nest at the same time in autumn, while clarifying that the number in this nest could not be established from the outside. This general reference should therefore not be turned into a tally for the Grund operation.

An established species that still needs monitoring

The Neobiota information sheet, which covers exotic species in Luxembourg, classifies Vespa velutina nigrithorax as established in the country. It dates the first confirmed observation in the wild to 2 September 2020. It also notes that a report in 2012 was based on confusion with the European hornet, Vespa crabro.

This precedent gives a practical reason to take care over identification. A large insect, unusual colouring or a quickly taken photograph is not always enough to identify the species. A documented report makes verification possible; it does not automatically confirm that the insect is an Asian hornet or that a nest is present.

Carole Krier says her team had received reports relating to 129 nests. This is a figure reported at the time of the report and is still provisional. It is neither the total number of nests across Luxembourg nor, without further clarification, the number of nests actually destroyed. Neobiota publishes other figures for different years and areas: adding them together would produce a misleading tally.

Effects on other insects

The Asian hornet is an insect predator. The scientific information sheet highlights in particular the pressure it can exert on bees and other pollinators. RTL also describes it foraging around ivy that is still in flower. The issue therefore goes beyond the mere presence of a large insect near homes.

Defending the nest is different from an individual being observed foraging. In the report, Carole Krier stresses this distinction: hornets can react aggressively when someone approaches their colony. Keeping your distance and avoiding disturbing the nest remain essential, even when activity seems low.

Neobiota advises against non-selective traps, including those intended for queens in spring, because of their effects on non-target species. An action presented as a way of controlling a predator can therefore catch other insects. Effectiveness and unintended effects must be considered together.

Report it according to the location, and do not intervene yourself

The recommended course of action given by Neobiota depends on the circumstances. An isolated sighting can be reported on a nature platform such as iNaturalist. For a nest on private property in a residential area that could pose a risk, the information sheet directs people to a specialist company. For a nest in a public place or on a public building, it refers them to the Nature and Forestry Administration. Problems involving beehives also come under the Luxembourg Veterinary and Food Administration.

Local monitoring therefore combines identification, assessment of the circumstances and intervention by the appropriate professionals. Removing the nest in the Grund resolves a specific problem; managing an established species, however, requires ongoing monitoring and responses that also protect other insects.