On a sunny autumn day, dozens of them appear on the outside wall or the window frame and, a few days later, you find ladybirds in the house: by the glass, on the windowsill or on the ceiling. Very often it’s the Asian harlequin ladybird, an invasive species that is already present in much of Europe and looks for a warm, dry place to spend the winter. It isn’t dangerous, but it is a nuisance. Here’s how to remove them without stains and stop them getting in.
Why do ladybirds come into the house?
The harlequin ladybird spends the winter in groups. From late September, and especially in October and November, it flies on sunny afternoons towards warm, highly visible buildings: light-coloured south- or west-facing walls, tall blocks of flats and houses next to parks or wooded areas. It squeezes in through gaps in window frames, the roller shutter box, air vents and the edge of the roof.
Wherever a group has spent the winter, a scent trail is left behind. That’s why they tend to return to the same spot year after year.
Harlequin or native ladybird?
The harlequin ladybird is slightly larger than most native species and comes in a wide range of colours: from yellow or orange with lots of spots to black with red markings. It can usually be recognised by its white pronotum (the area between the head and the wing cases) with a black M- or W-shaped pattern. The seven-spot ladybird, which is red with a black pronotum and two small white patches at the corners, almost always spends the winter outdoors, among dry leaves and tufts of grass.
Do they cause any harm?
To your home, very little: they don’t chew wood or fabric and they don’t breed indoors over the winter. But when they feel threatened, they release a strong-smelling yellow liquid that stains curtains, walls and furniture. Occasionally they give a small nip on the skin, like a slight prick. If you have a dog or a cat that eats anything that moves, keep an eye on them: ladybirds taste bitter and can irritate their mouth. If your pet drools, paws at its mouth or goes off its food after eating one, call the vet.
How to get ladybirds out of the house without stains
There’s no need for any insecticide: a vacuum cleaner and a little patience are all you need.
- Don’t squash them. A squashed ladybird leaves a yellow stain and a bad smell.
- Vacuum cleaner with a stocking. Put an old stocking over the tube, hold it in place with a rubber band and push the toe of the stocking a few centimetres into the tube. That way the ladybirds stay in the stocking and don’t reach the bag. Use the lowest power setting.
- Take them outside. Release them away from the house, for example under a hedge or among dry leaves, so they can spend the winter there.
- Only a few? Gently nudge them onto a piece of paper or trap them under a glass and take them outside.
- Already got stains? Dab them straight away with a cloth dampened with lukewarm water and a little washing-up liquid; test it first on an inconspicuous area.
Indoors, it’s best to avoid insecticide sprays: pets and children may end up coming into contact with them. And if you have a cat, don’t use essential oils such as tea tree or eucalyptus either: many are harmful to cats.
How to stop them coming back
- Seal gaps. Check the frames, the joint around the windowsill and the roller shutter box. Use draught-proofing strips or silicone on gaps around doors and windows.
- Insect screens. A fine-mesh insect screen keeps them out even when you air the room. The same screens also keep out stink bugs and spiders.
- Air vents. Don’t cover them with tape: the house still needs to be ventilated. A vent with an insect mesh does help, though.
- Clean where they gathered. Wipe the frames and the outside wall next to the window with a cloth, water and a little soap. This reduces the scent trail that can attract others the following year.
- Windows closed on sunny afternoons. They fly mainly around midday and in the afternoon, when the sun is shining on the wall. At those times, open the windows only as much as you need or air the room through a window with an insect screen.
When does it end?
When the temperature drops, they stay still and hidden. On mild winter days or in a heated room they may reappear, and in spring they’ll want to get out: open the window and let them go. If they come back in large numbers every year, it’s worth sealing the gaps properly or asking a pest control company for advice.
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