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Asian ladybirds in France: how to keep them out of your home
The insects can gather by the hundreds or even thousands inside homes as they seek shelter from the cold
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As autumn settles in and temperatures begin to drop, Asian ladybirds can gather outside homes, looking for shelter before winter.
The insects, known as Asian ladybirds or lady beetles (Harmonia axyridis), were brought into France in 1982 and can now be found throughout the country.
However, although they may look pretty, they can cause quite a nuisance in autumn as they can gather “by hundreds or even thousands” inside homes, according to the Forêt d’Orient Regional Natural Park biodiversity observatory.
Asian ladybirds were also reported in large numbers in France last autumn, with residents in several departments finding them inside their homes.
This is because as winter approaches, they are looking for somewhere to protect themselves from the cold and can get inside homes through very small cracks and gaps.
The large numbers are not considered dangerous, however. The observatory describes them as harmless to humans, while the CPIE des Pays de l’Oise, an environmental non-profit organisation, advises homeowners to focus on preventing them from getting inside rather than using insecticides.
They can, however, become a nuisance when present in large numbers.
Even though they do not damage homes, they can leave yellowy orange stains behind if crushed and can also release a defensive substance with an unpleasant smell when disturbed.
They may often be mistaken for native ladybirds because their colouring varies considerably. The Asian species can have different numbers of spots and colours, but a distinctive feature is often the pale marking behind the head, which can resemble the letter M.
The species can also compete with France’s native ladybirds. Asian ladybirds eat large numbers of aphids, but they can also eat the young of other ladybird species, according to the Forêt d'Orient biodiversity observatory.
How to prevent them from getting inside
To reduce the chances of Asian ladybirds getting inside, experts recommend sealing potential entry points, including cracks and gaps around windows and doors.
The CPIE des Pays de l'Oise also recommends installing draught excluders around doors and sealing other spaces through which the insects could enter.
If a few do make it inside, they can be gently captured and released outside. However they are largely inactive during wintering and leave again in spring.
Insecticides are also not recommended as Asian ladybirds are relatively insensitive to them, making prevention a better option.
