Killer ladybird invasion takes hold in Scotland

KILLER alien ladybirds are breeding in Scotland for the first time, experts have discovered.

A larva of a Chinese harlequin ladybird (Harmonia axyridis) has been spotted in Glasgow – providing the first evidence that the species is breeding in this country.

Previously, only a handful of the insects have been seen in Scotland, meaning there was hope they would not take hold.

Now experts say there may be little that can be done to stop their spread.

Harlequin ladybirds, introduced from China to control aphids, are larger than our native insects.

They eat native ladybirds, butterfly eggs and other insects, and have caused havoc in other European countries and the south of England.

They spread rapidly, putting other species at risk.

Craig McAdam, conservation officer (Scotland) for Buglife, the invertebrate conservation trust, said the discovery was bad news.

"The possibility that there is now a breeding population of the harlequin ladybird in Scotland is extremely worrying," he said.

"Buglife believes that the issue of invasive species such as the harlequin ladybird should be taken very seriously.

"The consequences of inaction on this issue are potentially highly damaging and costly to reverse."

The harlequin larva was discovered by RSPB Scotland employee and entomologist Norman Storie.

He had been challenged to find another, rare type of ladybird in the city by a friend.

Instead of finding the species he was looking for, a 14-spot, he discovered the 6mm-long baby harlequin.

It was crawling around on top of an electricity street lighting box near Kelvingrove Park in the West End in the sun.

Mr Storie kept the larva, in the hope that it would pupate and turn into a harlequin – so he could prove it was that species. However, it died before that happened.

But experts have been able to identify the species from the larva. The dead larva has been donated to the Hunterian Museum at the University of Glasgow.

A single ladybird can lay 1,000 eggs, meaning there are likely to be further baby harlequins in Glasgow.

The most common form of harlequins in the UK are either orange with 15-21 black spots or black with 2-4 red or orange spots. They were introduced to both America and Europe as a form of aphid pest control in the 20th century.

However, they spread very quickly and there are fears they put other species at risk.

Harlequins were first recorded in Britain in 2004, but are already now widespread in the south of England.

Paul Walton, Head of Habitats and Species for RSPB Scotland, said: "When people move animals and plants around the world and release them, resident wildlife sometimes cannot cope.

"The harlequin ladybird is a new predator introduced by people and might have a significant impact on other wild insects. Little can be done to slow its spread now, but we should see this as a wake-up call.

"We should all be vigilant to prevent the introduction of damaging species outside their natural range, particularly in lakes, rivers and islands."

Robin Payne, invasive species expert at Scottish Natural Heritage, agreed that the harlequin's breeding was very worrying. "It's a matter of serious concern," he said. "Sadly it seemed inevitable that we would find it becoming established in Scotland in time."

The Harlequin Ladybird Survey, which maps the spread of the species in the UK with the help of sightings from the public, describes it as "the most invasive ladybird on Earth".

It warns that the creature has the potential to jeopardise the future of many of the 46 species of ladybird resident in Britain.

Anyone who believes they have seen a harlequin can send a photo to the Harlequin Ladybird Survey for identification.