Ninja ladybugs enter houses en masse before winter. It’s an invasive species, but it has its advantages

Prof. Twardowski pointed out that the topic of Asian ladybugs (also called harlequin or ninja ladybugs) usually appears once a year – in autumn.

Then, looking for a place to hibernate, these insects sit on windows and sunny walls and try to get into our apartments. We then talk about a plague and multiply ways to get rid of it. But its discomfort lasts only a few days. For the rest of the year, no one talks about it, which is a pity, because it is very useful, eating e.g. aphids – said the head of the Entomology Department at the Wrocław University of Environmental and Life Sciences.

Asian ladybugs enter houses because they mistake them for crevices

The scientist emphasized that representatives of this species usually find shelter under stones and in rock crevices. – Here they hide in buildings, instinctively mistaking them for rocky hills. The cracks in the windows are one of their favorite places, he said. He added that in a week or two, when Asian ladybugs find a place to spend the winter, they will disappear from the sight of residents of Polish cities.

Prof. Twardowski also emphasized that the Asian ladybug – although it can be a nuisance – does not pose a direct threat to humans. It is true that an insect bite is unpleasant and may cause redness or itching, but it is not aggressive, like, for example, a wasp. – A ladybug will not attack us on its own, in order to bite it must be crushed, for example, and sometimes it bites when we catch it and hold it in our hand. It is also not dangerous for humans, although, for example, when a cat bites it, and we have had such cases, the toxins it secretes may irritate its esophagus – explained the scientist.

There are 76 species of ladybugs in Poland. The color of the Asian ladybug is yellow, orange to red, but it can also be black with red dots. it has a black M-shaped drawing just behind its head and a delicate hump on its back.

The Asian ladybug is invasive but beneficial

The Asian ladybug is an invasive species that displaces native ladybugs. – In practice, however, it is a beneficial insect – emphasized Prof. Twardowski.

The Asian ladybug was introduced to California in 1916 to protect crops from other insects. As a result, the insect has taken over almost all of North America, South America and Africa. In the 1980s, it was imported from Canada to , hoping that it would cope with the aphid plague. In Poland, the first individuals were observed in Poznań in 2006.

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