The UK has so far successfully fought off invasion by the Asian hornet – thanks to vigilant members of the public.
A new study has shown that although the UK has suitable climate and habitat for the yellow-legged hornet, also known as the Asian hornet, effective action has prevented this voracious predator of pollinators from establishing here.
The invasive non-native species, which can kill 50 bees a day, has devastated honeybee colonies in France and Italy.
It arrived in France in a container of pottery from China about 20 years ago, then spread rapidly across the continent, and was first seen in the UK in 2016.
There have been regular sightings in the UK including 44 confirmed so far this year, mostly in Kent and East Sussex, but the National Bee Unit responds rapidly to reports, destroying the insects and nests found.
The UK Centre for Ecology & Hydrology (UKCEH) has led a study to assess the environmental suitability of European countries for establishment and spread of the yellow-legged hornet (Vespa velutina).
This work was the first to consider the potential extent of invasion by this species that would have occurred in the UK, Germany and the Netherlands if rapid eradication had not taken place.
The EU-funded study, published in the Journal of Applied Ecology, found that over 1,500km2 in the UK would have been colonised by 2020 without action to tackle the invasive non-native species.
Asian hornets were first introduced to the UK in 2016 but began to spread far more aggressively in recent years. But experts say the UK has so far successfully fought off invasion by the Asian hornet – thanks to vigilant members of the public
An immediately identifiable feature of the Asian Hornet is its bright yellow leg tips compared to the European’s brown legs
Lead author Dr Richard Hassall of UKCEH explains: ‘No significant spread has yet been reported in UK.
‘While there has been recent establishment in Germany and the Netherlands, our predictions suggest that the attempts to tackle the yellow-legged hornet in these countries have so far been successful in limiting its spread.
‘This is due to the fantastic efforts by vigilant members of the public who report suspected sightings of yellow-legged hornets, then rapid action by the authorities to locate and eradicate the insects and nests found.
‘Significant resources have gone into monitoring and slowing the spread of this invasive non-native species in the UK and parts of Europe, so it is encouraging to find these efforts appear to have been effective.’
UKCEH oversees the alert system for Britain which enables people to report potential sightings of a number of priority invasive non-native species.
The yellow-legged hornet is one such species and there are various ways that people can submit their reports.
The Asian Hornet Watch app has received around 12,500 reports of sightings from the public in the UK so far this year.
But only a fraction of these are confirmed as yellow-legged hornet, with most observations actually of the native European hornet or hoverflies and other insects that look similar to the yellow-legged hornet.
Britons have been urged to be on the lookout for invasive Asian hornets (pictured) as 25 sightings have already been reported this year
The Asian hornet has recently been renamed the yellow-legged hornet in part to aid correct identification.
In addition to checking the guides on the app and online, the public is asked to submit a clear photograph with their recorded sightings to help experts quickly identify whether it is a yellow-legged hornet.
Professor Helen Roy of UKCEH and the University of Exeter, a co-author of the study, said: ‘We are grateful to everyone who is helping to track the spread of the yellow-legged hornet.
‘The contributions of volunteers to citizen science initiatives such as the Asian Hornet Watch app are inspiring.
‘The yellow-legged hornet is a voracious predator and has caused notable losses of honeybees in parts of Europe, and we predict there would be major impacts to wild pollinators in the UK if it establishes here.’
Yellow-legged hornets were first introduced to the UK in 2016 but began to spread far more aggressively in recent years.
The species’ activity has so far been largely in the South East of England, with Kent being the most affected.
However, they have also appeared in Sussex, Surrey, Hampshire and London, with isolated confirmed sightings across parts of South-West England and as far north as Yorkshire and Northumberland.
So far one hornet nest has already been identified and destroyed. Pictured, an Asian Hornet nest on a roadside cafe near Canterbury in May this year
Recent modelling shows that every part of the UK, with the exception of some areas in Scotland, has a habitable climate for these invasive insects.
That is particularly worrying since Asian hornets feed on our native pollinators like wasps and honey bees.
Each hornet nest can eat about 11 kilos of insects in a year and they prefer to predate social insects honey bees which have little defence against these fierce hunters.
The invasive species is often mistaken for the native and ecologically important European hornet.
‘One of the easiest ways to identify them is by looking at their legs,’ said Professor Helen Roy, an ecologist at UKCEH and the University of Exeter.
‘Yellow-legged hornets have yellow and brown on their legs, whereas European hornets’ legs are only brown.’
The Asian hornets are also smaller and more slender than their European counterparts and will appear orange when viewed from the front.
If you do see an insect you believe to be an Asian hornet, you are urged to report it via the Asian Hornet Watch app or online via UKCEH’s online reporting form.
All sightings reported on the app are double-checked by UKCEH, but ensuring you only report genuine sightings helps resources be used more effectively.
Professor Roy adds: ‘The vast amount of data we receive from citizen scientists is helping to develop the alert system and our experiences are proving useful for sharing with others in developing similar systems around the world.’
