After the arrival of the invasive yellow-legged hornet (Vespa velutina) in Spain, fear spread faster than the hornet itself. Researchers are working to balance awareness with evidence, and a new study finds no increase in deaths attributable to stinging insects since the hornet’s arrival, despite alarming headlines. (Photo by Bernard Noguès via iNaturalist, CC BY-NC 4.0)

By Carolyn Bernhardt

As climate change affects where insect species live and thrive, it reshapes human health risks. The spread of the yellow-legged hornet (Vespa velutina), represents one striking example. The insect’s recent arrival in Spain has sparked alarming headlines and growing public anxiety about deadly encounters.

Despite this mounting concern, scientists say we still don’t have a full picture of how dangerous this invasive hornet truly is at a national level—leaving a gap between perception and evidence that a team of researchers at the University of the Balearic Islands in Spain is racing to close.

The scientists published an article in March in the Journal of Medical Entomology on their study assessing the current situation and evaluating whether the expansion of V. velutina is associated with an increased risk of death.

Data Versus Drama

María del Mar Leza Salord, Ph.D.

Cayetano Herrera, Ph.D.

In their retrospective analysis, the team examined officially certified deaths attributed to contact with hornets, wasps, and bees in Spain between 1999 and 2023, spanning the establishment and spread of V. velutina—118 records in all.

They didn’t find evidence that deaths are increasing over time or happening more in certain months of the year. Men and women were affected at similar rates, and it didn’t seem to matter whether the sting happened indoors or outdoors. Even in areas where the invasive yellow-legged hornet is more established, there wasn’t a clear link to higher death rates. The only hint of a pattern was that older adults (ages 60–99) might be at slightly higher risk, but even that result wasn’t definitive.

“The most striking [thing about our] finding[s] was the contrast between our results and the prevailing media narrative,” says Cayetano Herrera, Ph.D., a postdoctoral researcher in the Department of Biology at the University of the Balearic Islands, co-author of the study with department colleague María del Mar Leza Salord, Ph.D. Herrera says public discourse frequently highlights the yellow-legged hornet as an emerging lethal threat, heightening the wider perception of danger.

“Logically, one might expect that a greater presence of an invasive species [that can sting] would lead to increased contact and, consequently, higher mortality,” he says, adding that even though the yellow-legged hornet is spreading quickly, deaths from stinging insects in the broader Hymenoptera group haven’t increased overall. In fact, across Europe, the hornet’s impact on human mortality appears similar to that of native bees and wasps when you account for how often people are exposed.

According to Herrera, these insects become dangerous through two primary mechanisms: severe allergic reactions and high venom levels from multiple stings. “The risk of severe anaphylaxis is significantly higher for individuals with pre-existing allergies, the elderly, or those with underlying health conditions.”

Herrera also says the biggest challenge with this study was messy, incomplete data—especially after a few highly publicized deaths in Spain in 2025. The team relied on national death records from the Spanish National Statistical Institute database, which lumps all stings from bees, wasps, and hornets into a single category, making it hard to parse the impact of the invasive yellow-legged hornet.

To work around this, the researchers compared death rates in areas where the hornet is present versus where it isn’t and pieced together its spread using a mix of scientific studies and regional reports to fill gaps in official data.

Smarter Surveillance

For the future, the scientists call for continued surveillance, clinical and ecological data integration, and accurate public communication. “It is crucial to inform the public that this is an invasive species capable of stinging and that it is colonizing new territories across multiple continents,” says Herrera. “However, the media should also acknowledge the current lack of scientific literature regarding its specific epidemiology.”

That doesn’t mean people should let their guard down. The hornet can still be dangerous, especially if its nest is disturbed. “We hope for coverage that differentiates perceived threats from documented epidemiological risks to avoid unnecessary social alarm while promoting safety,” says Herrera.

Population-level mortality is the most severe but least frequent clinical outcome of Hymenoptera exposure. “Literature suggests that more subtle clinical shifts may be occurring that do not result in death but still impact public health,” Herrera says. The scientists call on future research to focus on the insect’s impact on systemic allergic reactions and healthcare demand. They also suggest expanding the territory of these studies to identify regional variations in risk.

Herrera also notes established scientific evidence of the negative impacts of V. velutina on honey bees, apiculture, wild insect populations, and essential ecosystem services, such as pollination. “While we found no significant association between the presence of the species and mortality rates, this does not mean the situation is static,” he says. “Previous research by our group has also highlighted its detrimental effect on local biodiversity.”

Climate change models also predict an expansion of this species’ distribution, which could further alter its current risk profile. “Therefore,” Herrera says, “ongoing surveillance of other health parameters, such as allergic reactions, is essential.”

Carolyn Bernhardt, M.A., is a freelance science writer and editor based in Portland, Oregon. Email: [email protected].