A species of ladybug, that is new in Denmark, enjoys not only the outdoor life but also been found in Danish homes.

We all know it – the beetle with the cute name, red colour and black polka dots: the ladybug. Now it turns out that Denmark’s nature not only includes Danish ladybugs but also a new species that originally comes from East Asia.

Not only that – the Asian ladybug has been found winter snoozing in an apartment in Copenhagen. The Danish Pest Infestation Laboratory at the Faculty of Agricultural Sciences (DJF,) University of Aarhus, is following the spread of the little ladybug closely.

The six-legged immigrant from Asia, Harmonia axyridis, was first discovered outdoors in Denmark in 2006. The Asian ladybug has a great appetite for aphids in the summer – to the delight of gardeners and organic farmers.

- Unfortunately, it prefers to stay indoors in the winter as opposed to most other ladybug species, that overwinter under bark, stones and grass, explains senior scientist Tove Steenberg from the Danish Pest Infestation Laboratory.

- We received the first query about overwintering ladybugs in an apartment in Copenhagen in October. In the years to come we shall see if the Asian ladybug becomes a winter nuisance in Denmark, she says.

The Asian ladybug, which stems from East Asia, has established itself in the United States and since 2001 in wide parts of Europe. Besides being able to outcompete other species of ladybug, it has a reputation for invading houses in great numbers in the autumn, where it stays for the winter.

If there are many ladybugs, it can be quite a nuisance to share your house and home with the little beetle. Ladybugs excrete a stinky liquid when disturbed. They can also dirty curtains and rugs. Cases of allergic reactions to the Asian species of ladybug have been documented.

Often the same houses are selected for winter quarters year after year. You can try to fend off the ladybugs by filling in cracks to avoid that the bugs make their way into the house. If the ladybugs have already invaded the house in annoying quantities, then you can remove them using a vacuum cleaner.

The Danish Pest Infestation Laboratory, which works with pests in homes, among other tasks, has followed the spread of this invasive species of ladybug up through Northwestern Europe. In Europe it was first found in Belgium in 2001.

In order to follow the spread of this new member of the Danish fauna, the Danish Pest Infestation Laboratory is on the lookout for overwintering ladybugs in houses or other buildings.

For more information please contact: Senior scientist Tove Steenberg, Department of Integrated Pest Management, Danish Pest Infestation Laboratory, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 3938, e-mail: Tove.Steenberg@agrsci.dk

Text: Janne Hansen

Photo: Jørgen Christensen