A "voracious predator" which is threatening native ladybird species is spreading across the UK just two years after its first sighting in Essex.
The harlequin ladybird, Harmonia axyridis, is clustered around the south-east of England, but it was also spotted in Wales in August.
It is aggressive, eats more, and can even turn on other ladybirds for food.
Experts have warned some of the UK's rarer ladybird species "will probably disappear in the next 10 years".
The harlequin, originally from Asia, was used as a bio-control agent to eat insects and stop them destroying crops.
But ladybird expert Dr Mike Majerus said: "In North America and north-western continental Europe, it's simply out-competing the native ladybirds.
"It eats all their food and if it runs out of the food it then starts to actually eat other species of ladybird - the larvae, the eggs, the pupae."
HOW TO SPOT A HARLEQUIN
Tends to be rounder in shape than most native UK species
Can reach up to 8mm in size, a little larger than common ladybirds
It has a white plate just behind the head with a big, black M-shaped marking on it
Sighted bugs can be red, orange or black with between 15 and 20 spots
Others may be black with between two to four orange or red spots
He said about half of the UK's 46 ladybird species were "really under threat".
Dr Majerus was on the case when the first harlequin was sighted in the gardens of a pub in Sible Hedingham, Essex, in October 2004.
"I'd actually been expecting it," he admitted.
"The thing's become, in the past three or four years, very common in Holland, Belgium and northern France, and we've just been waiting for it to come across the Channel."
Gardeners and horticulturalists have been helping to monitor the spread of the harlequin by reporting sightings to the UK Ladybird Survey.
Project officer Peter Brown said the invader was not only a nuisance to other insects, but humans as well.
"They come to houses in very large numbers at this time of year and they have stuff called reflex blood, which is yellow fluid which can stain furnishings and really cause quite a nuisance in the house."
Researchers at the Anglia Ruskin University in Cambridge are now trying to develop a chemical bait which would allow them to lure the ladybirds to "a place where we can remove them".
Latest figures show the harlequin has spread as far west as Cornwall and as far north as Yorkshire.