Harlequin ladybird threat

A new ladybird has arrived in Britain. But not just any ladybird: this is the harlequin ladybird, the most invasive ladybird on Earth. It has invaded much of north-western Europe and arrived in Britain in summer 2004, spreading at a rate of 100 km a year.

There are 46 species of ladybird resident in Britain and the recent arrival of the Harlequin has the potential to affect many of these. The Harlequin is an example of a problematic invasive non-native species, a species which is not native to an area and causes problems either for native species, ecosystems or for people. These species may be introduced (such as the rabbit into Australia, or the harlequin into Britain), or they may arrive on their own but then are only considered non-native if they are non-native to the region in which they arise from.  Harlequin ladybirds are considered an invasive non-native species because they are predicted to out-compete some native species and cause a nuisance to humans by clustering in large numbers in houses.

What should we do about invasive non-native species, though? Should we intervene to control them, or let nature take its course? These are tricky issues for conservationists and for society in general. What do you think?

Ladybird Parasite Survey
Scientists at the Centre for Ecology & Hydrology (CEH) and University of Cambridge are working together to better understand the natural enemies that attack ladybirds. They would like your help. Visit the BBC Breathing Places website to find out more.

 Extra information

• Learn about recent research on the spread of harlequins in Europe.
  
• The scientific name for the harlequin ladybird is Harmonia axyridis.
• The harlequin was introduced to North America in 1988, where it is now the most widespread ladybird species on the continent.
• A national Harlequin Ladybird Survey, which everyone can take part in, is monitoring its spread across Britain to assess its impact on native ladybirds.
• Read a blog by Dr Helen Roy, ladybird expert at the Centre for Ecology & Hydrology.
• Harlequin ladybirds are one of many problematic invasive alien species. Find out how an 'alien' moth is threatening conker trees.
• This map shows the spread of the harlequin ladybird in Britain up to July 2009:

(Note: Maps from the Harlequin Ladybird Survey website, where more up-to-date maps may be available)

Photo of harlequin ladybird copyright Scott Thompson

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