The European invader killing off our ladybirds

Britain's ladybirds are at risk of being wiped out by a killer European invader, scientists warned today.

They say this year could see numbers of the invading harlequin ladybirds overtake the native species for the first time.

They called on Londoners to watch out for the distinctive black insect and help track its progress.

The harlequin (Harmonia axyridis) was first spotted in Britain in 2004. It is a voracious predator that easily out-competes home bugs for food and also feasts on their eggs.

The insects are emerging from hibernation in record numbers.

"Numbers of the harlequin ladybird are rising rapidly across the UK and they are now even in Scotland," said Peter Brown of the Centre for Ecology and Hydrology, which is conducting a national survey. "I think we are going to see them overtake the indigenous ladybirds very soon. In London in particular there are huge numbers, as they love the trees in the capital's parks."

The insect has a huge appetite for greenfly, leaving little for the native species who then starve. The harlequin will also turn on other ladybirds if food resources diminish.

"They will also prey on other types of insects, eating butterfly eggs, caterpillars and lacewing larvae," said Mr Brown. "There is really very little we can do to stop them."

Originally from Asia, the harlequin was probably imported into the UK on plants from continental Europe. The insects have taken hold in many parts of London.

Daisy Barlass, nine, from Teddington, visited Marble Hill House last Sunday with her family. She said: "I saw lots of nasty looking, black ladybirds. There must have been dozens of them, so I avoided going near."

Mr Brown called on people to log sightings of the harlequin on a government-backed website, www.harlequin-survey.org.