The killer Asian hornet is "wreaking havoc through Europe" and Brits are urged to take action against the "dangerous" and "invasive" beasts.
The UK is nearing 'Asian hornet week', when the potentially lethal invaders are more like to be spotted.
One sting from the hornets can be fatal to a human if they enter anaphylactic shock - a rare but severe allergic reaction - and a large number of stings can lead to organ failure.
People have been hospitalised in France after suffering anaphylactic shock as a result of multiple stings.
Humans have been attacked after disturbing the hornets which charge in groups as soon as one feels a nest is threatened.
There is some suggestion their sting releases a pheromone which alerts other hornets to attack.
The winged assassins have a more serious sting due to their size and it can cause great pain, but deaths are rare and primarily from anaphylactic shock, as with any venom.
They are not to be confused with the Asian giant hornet - whose stings killed 41 people in Shaanxi in China in 2013.
Originating, as the name suggests, in Asia, they have been spotted across Europe, arriving in France from China in 2004.
And there are fears of them crossing the channel in large numbers and causing problems in the UK - where sightings were first reported in 2016.
On top of the fears of a nasty sting for humans, beekeepers are terrified that the invaders could could cost the economy millions of pounds, as they are thought to already be having a devastating impact on Britain's already dwindling honeybee population.
Now beekeepers are calling on people to help defend Britain by reporting sightings and using their smartphones to capture evidence of the yellow-legged insects, who can decimate native pollinators.
The warning comes ahead of Asian hornet week, between Monday, September 7 and Sunday, September 13, which is a key time to spot the Asian hornet.
Lynne Ingram, co-ordinator of Somerset’s Asian hornet action teams, said: "See it, snap it and send it!
"We need the public’s help to save our bees from the Asian hornet which has been wreaking havoc through Europe since 2004."
Mrs Ingram, a beekeeper with 30 honeybee colonies near the town of Bridgwater, added: "Now is the time to spot the hornets so that their nests can be destroyed before they multiply.
"If you see a hornet take a photo, send it to us and we’ll do the rest. Or use the official Asian hornet watch app and report it.
"The arrival of the hornet in Britain is especially bad news for bees - a favourite food source - and a single hornet can completely devastate a beehive, devouring up to 60 at a time."
A report by French scientists published this year in the journal NeoBiota, found the environmental destruction and cost of fighting the invasion could cost the equivalent of £7.6million pounds a year.
They have a negative impact on ecosystems, contributing to a global decline in pollination by targeting other insects and native bees.
Honey production can also be impacted.
The researchers estimated that the Asian hornet colonised most of France, advancing at a rate of 60 to 80 kilometres per year.
Spain was invaded in 2010, Portugal and Belgium in 2011, Italy in 2012 and Germany in 2014.
Experts will lay traps with bait to capture and kill the hornets, and will destroy nests when they are discovered.
But each year in France only 30 to 40 per cent of detected nests are destroyed, if they are too close to humans or beekeepers.
And fighting the invasion will be costly, with the price of nest destruction being £7.6million in the UK - and £10.5million in France.
rofessor Franck Courchamp said: "In 2006, only two years after the hornet was first observed in France, three departments were already invaded and the cost of nest destruction was estimated at 408,000 euros.
"Since then, the estimated yearly costs have been increasing by about 450,000 euros each year, as the hornet keeps spreading and invades new departments.
“Definitely more actions need to be taken in order to handle harmful invasive species - one of the greatest threats to biodiversity and ecosystem functioning."
In the autumn Asian hornets can be spotted on flowering ivy, fallen fruit and hawking honeybees outside their hives as well as catching other pollinators.
Asian hornets have been spotted in the UK and are rampant on the Channel Islands after they were accidentally introduced into southern France from China.
An Asian hornet is about twice the size of a honeybee, has an orange face and a dark abdomen with a yellow fourth segment.
Its thorax is entirely dark brown or black and velvety and the insect has bright yellow tips to its legs.
A single Asian hornet can kill 60 bees a day, with a nest containing up to 6,000 workers and up to 350 queens.
Nicola Spence, Chief Plant Health Officer, said: “By ensuring we are alerted to possible sightings as early as possible, we can take swift and effective action to stamp out the threat posed by Asian hornets.
“While the Asian hornet poses no greater risk to human health than a bee, we recognise the damage they can cause to honey bee colonies and other beneficial insects.
"Please continue to look out for any Asian hornets and if you think you’ve spotted one, report your sighting through the Asian hornet app or online.”
The University of Exeter is carrying out research into the impact Asian hornets are having on honeybees and other pollinators where they become established.
Research Fellow and behavioural ecologist Dr Peter Kennedy said: "Asian hornets are anticipated to be a significant mortality factor influencing a broad spectrum of insects, including honeybees, on top of existing stressors (habitat loss, disease, pollution, climate change, etc) that already impact our beleaguered native pollinator community.
"Worldwide, invasive non-native species are recognised as being a serious threat to biodiversity, and it is consequently important that we encourage the public to be informed, vigilant and proactive in reporting the presence of Asian hornets and other invasive species."
Sightings can Asian hornets are a notifiable invasive species and can be reported with a photo using the Asian Hornet Watch app, via email asianhornet@somersetbeekeepers.org.uk or at altertnonnative@ceh.ac.uk or at www.nonnativespecies.org/alerts/asianhornet.
