On the hills above Cornol in the canton of Jura, scientists are testing unusual new defences in the fight against the invasive Asian hornet (Vespa velutina): electric harps and hive “muzzles.”

The Asian hornet first arrived in southwestern France in 2004 and has since spread across much of Europe, including Spain, Portugal, Italy, Germany, Belgium, the UK, the Netherlands, and Switzerland.

The species is feared to pose a major threat to honey production, pollination services, biodiversity, and native hornet, bee, and wasp populations.

How well these devices protect bees without harming native wildlife

The experiment is led by the Fondation Rurale Interjurassienne (FRI) and aims to measure how well these devices protect bees without harming native wildlife. It is part of a bigger project led by CABI, with the goal to protect pollinators against the invasive yellow-legged Asian hornet.

Nine beehives in Cornol are taking part in the trial. Three have been fitted with electric harps – frames strung with alternating positive and negative wires. Bees, which only touch one wire, pass safely through, but hornets attempting to breach the barrier receive a fatal shock.

Another three hives have been fitted with protective muzzles, wire fences that block hornets from hunting at the hive entrance, allowing bees to forage undisturbed. The final three hives have been left unprotected to serve as controls for comparison. The trial is repeated in nine locations in the Swiss canton of Jura.

First time such trials have been carried out in Switzerland

“This is the first time such trials have been carried out in Switzerland,” said Dr Lukas Seehausen, a research scientist based at CABI’s Swiss Centre in Delémont. “We want real quantitative and qualitative data to see which method, if any, is worth recommending.”

Dr Julie Hernandez, a honeybee specialist at FRI, adds: “We are using the honeybee colony structure evaluation for field surveys to determine if the health of bees attacked by the Asian hornet can be improved through judicial use of the devices.”

The tests will also examine whether the devices affect native species. Similar technology has already been used in France and Spain, where harps reportedly killed hundreds of Asian hornets per day in heavily infested areas. Dr Seehausen cautions that such results are unlikely in Jura, where hornet numbers are lower.

In Switzerland, CABI scientists first confronted the Asian hornet in 2020, tracking and destroying a nest in Le Noirmont using radio telemetry. That same year, Asian hornets were seen attacking local hives for the first time.

Sting can be dangerous for allergy sufferers

While no more aggressive to humans than the native European hornet, the Asian hornet is more numerous in areas it invades, and its sting can be dangerous for allergy sufferers.

For beekeepers, however, the threat lies in the hornet’s relentless predation on honeybees – something the team in Cornol hopes their electrified and fenced defences can stop.

Bees are vital for pollinating crops, and a decline in their numbers due to the Asian hornet predation could negatively affect food production.