Scientists in Spain are trying to find an underground nest belonging to the first southern giant hornets to be spotted in Europe.
The invasive insects, sometimes referred to as "murder hornets" because they are known to kill off beehives, can grow up to around 1.3 inches in length.
They are not to be confused with Asian hornets (Vespa velutina) which were confirmed to have survived a UK winter for the first time this year.
Both species are native to Asia and known to eat honeybees, but southern giant hornets (Vespa soror) are different because they build their nests underground.
They are also slightly larger than Asian hornets, which tend to be around an inch long.
There is no suggestion that southern giant hornets have been sighted in the UK.
However, scientist Omar Sanchez, lead author of a study into the sightings in Spain, said it was likely the species would be "detected again in other localities of Spain and probably Europe".
So far there have been two separate sightings of the insects in the northern city of Siero, in Spain's Asturias province, according to the study published in the Ecology and Evolution journal last month.
A pair of the hornets were spotted in March 2022 before another two were seen in October 2023.
'Bad effects'
Researchers believe they have a nest that dates back at least a year.
Mr Sanchez, a zoology professor at the University of Oviedo, and his study's co-authors found and captured the four hornets.
They then extracted DNA samples and conducted genetic testing and analysis to confirm the species.
The scientists believe the southern giant hornets likely first arrived in Spain on a cargo ship.
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Mr Sanchez said he expects the insects to impact the balance of the local ecosystem because they aggressively hunt native hornets, bees, butterflies, moths and flies.
He added: "A long-term decline in the bee population can affect the availability of honey and disrupt pollination processes on which many plants and crops rely."
Mr Sanchez also said that Asian hornets in Spain are already "causing serious damage to the beekeeping sector" and so the presence of southern giant hornets will "magnify the bad effects".
The scientist said researchers are therefore trying to find the nest so they can destroy it.
'Slaughter phase'
"It's a little bit tricky because this species makes their nest under the ground - more than 30 meters - so it is not easy to find. We are trying," Mr Sanchez said.
The insects are known to send out scouting teams to find beehives to prey on, according to research published in 2021.
The scouts then rub their bodies against the hive or nearby vegetation to signal others to join them, the study adds.
The southern giant hornets then enter a "slaughter phase" in which they can take out entire beehives in a matter of hours.
Mr Sanchez also said the insect's sting can be "very painful and long-lasting" for humans.