The Harlequin ladybird (Harmonia axyridis) is one of the most invasive species in the world. It took the Grey squirrel 100 years to spread throughout the UK – it has taken the Harlequin ladybird less than 5 years to do the same.
The Harlequin was introduced from Asia to North America in the 1980s to control aphids that were feeding on crops, however the ladybird quickly spread across the United States to become the most common ladybird there.
|Harlequin ladybirds (Harmonia axyridis) © Francis Rowland|
It takes its common name from the fact that over 100 different colour patterns have been recorded. Some specimens are reddish-orange with black dots, while others are black with red patches. This of course makes it difficult to identify.
Unlike most other ladybirds, the Harlequin doesn’t stick to one type of food. Once it has finished feeding on aphids in the crops it then turns its attention to other ladybird eggs and larvae and even the eggs and caterpillars of moths and butterflies. The main reason Harlequin ladybirds pose a threat to our native ladybirds is that they have such voracious appetites that they easily out-compete native ladybirds for food. This could mean that numbers of native species such as the Two-spot or Seven-spot ladybird are dramatically reduced, some species may even eventually be threatened with extinction here in the UK.
|Harlequin ladybird larvae eating an aphid © Francis Rowland|
The Harlequin has now spread across most of north-western Europe and in 2004 the first Harlequin was found in Britain. Since then it has spread northwards and in 2007 the first specimens were found in Scotland.
Although they are not dangerous to humans they do hibernate in large numbers in houses and other buildings. There are cases of tens of thousands of ladybirds being found in homes during the winter. In the spring the ladybirds become active again and look for a way out of the house.
Please get involved
This January the Harlequin Ladybird Survey is asking for your help. If you have either native Two-spot ladybirds or Harlequin ladybirds hibernating in your home they want you to count them and tell them how many there are. To find our more, and for more information on Harlequin ladybirds generally, click here.
If you would like to help Buglife work to protect our native bugs from invasive non-natives such as the Harlequin ladybird, please join us. It costs from just £18 per year. Please click here for further information and to join online.