Hunt for the harlequin – A UK survey for the world's most invasive ladybird
Britain's best-loved beetle, the ladybird, is under threat from the world's most invasive ladybird species - the harlequin ladybird
(Harmonia axyridis). To help the native ladybird, a national survey is taking place with the support of Cheshire Wildlife Trust.
Originally from Asia, the harlequin ladybird was first spotted in the UK in September 2004. Since then many sightings have been reported, but these have mainly been confined to the south east of Britain. Much more information is needed to discover the true extent of the threat to the native ladybird.
There are 46 species from the ladybird family (Coccinellidae) in Britain and the arrival of the harlequin ladybird is a potential threat to all of these. It is an extremely voracious predator that easily out competes native ladybirds for food. When their preferred food, of green fly and scale insects, is not available the harlequin readily preys on native ladybirds and other insects such as butterfly eggs, caterpillars and lacewing larvae.
Introduced from Asia into North America to control plant pests, the harlequin has spread across the states, becoming by far the commonest ladybird in less than 20 years.
It has been introduced into many countries as a biological control agent against aphid and scale infestations in greenhouses, crops and gardens. Populations have now established in north America, France, Germany, Luxembourg, Belgium, Holland, Greece and Egypt. In France, Belgium and Holland numbers are soaring annually.
They can disperse rapidly over long distances and so have the potential for rapid geographic expansion.
The survey is calling for all gardeners, farmers, wildlife enthusiasts and anyone with a love of ladybirds to examine trees, bushes and plants and record all ladybirds, including the harlequin, they find. Scientists from the University of Cambridge, Anglia Polytechnic University, the Biological Records Centre and the Natural History Museum will use the results of the survey to gauge how widely the harlequin has spread throughout Britain.
Chris Mahon, director of Cheshire Wildlife Trust, comments
“While the harlequin ladybird has not been spotted as far north as Cheshire, we should all be vigilant and report any sightings because of the potential threat this species presents to our own native ladybirds.”
How you can help
Monitoring the location of the harlequin is essential to understanding its impact upon not just our own ladybirds but other insects as well.
Dormant throughout the winter, ladybirds wake-up in March and April and begin looking for partners to mate with. Ladybirds are normally found wherever there is food for them. Any plant, shrub or tree with greenfly or scale insects may attract harlequins.
Surveyors are asked to report any sightings of the harlequin ladybird, including where it was found (where possible a grid reference or postcode), the date and how many ladybirds were there. A photograph of the ladybird would also help verification of each find.
How to recognise the harlequin ladybird
The harlequin ladybird is rounder in shape and slightly larger than most British species - measuring between 5-8mm.
Colour patterns vary greatly, but most harlequin ladybirds that have been found in Britain fall into three categories:
- Orange with between 15 and 20 spots
- Black with 2 orange or red spots
- Black with 4 orange or red spots
Just behind its head it has a white plate with a big black M' shaped marking on it.
For more information or to join the survey visit www.harlequin-survey.org or details can be sent to the UK Ladybird Survey, Biological Records Centre, Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Cambridgeshire, PE28 2LS.
To submit records of other ladybirds and for further information visit www.ladybird-survey.org.
The UK harlequin Ladybird Survey is a collaboration between the University of Cambridge, Anglia Polytechnic University and the Centre for Ecology and Hydrology. Sponsored by Defra and the Joint Nature Conservation Committee and supported by the National Biodiversity Network, the Natural History Museum, London/English Nature partnership and The Wildlife Trusts.