Pest Control
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Wasps are a summer problem, so a wasp crawling across the bedroom windowsill in January can be a surprise. It is almost always a queen that was hibernating in the loft, a wall or a stack of stored boxes, and has been woken too early by the warmth of the house.
What happens to wasps in winter
A wasp colony lasts one season. In late summer it raises new queens and males, and the new queens mate. As the weather turns cold, the old queen, the workers and the males die, and the nest is abandoned for good.
The new queens survive by hibernating. Each one finds somewhere dry, sheltered and undisturbed: a loft, a shed, a garage, a wall cavity, a stack of timber, under loose bark or in the folds of stored curtains and cardboard. She stays there, inactive, until the weather warms up in spring.
Why queens turn up indoors
A queen hibernating in or near a house can be woken early by central heating, a warm spell or a light left on near where she is resting. Once awake, she heads for warmth and light, which usually means a window. She will often be slow and sluggish, because there is no food for her and it is too cold outside to forage.
If you see wasps indoors in January, February or early March, they will almost certainly be queens rather than workers.
How to recognise a queen
A queen looks like an ordinary yellow and black wasp, with the same narrow waist, but she is noticeably larger, around 2cm long compared with roughly 1.2 to 1.7cm for a worker. A large wasp on its own, early in the year, moving slowly, is a queen.
Do queen wasps sting?
They can. Only female wasps sting, and a queen is female. A queen woken from hibernation is not aggressive and has no nest to defend, but she will sting if she is handled, trapped against skin or stepped on. Do not pick her up with bare hands.
What to do
- Let her out. On a mild day, open the window and let her find her own way out.
- Or catch her. Place a glass over her, slide a piece of card underneath, and take her outside or to an unheated outbuilding.
- Do not swat. Swatting at any wasp makes a sting more likely.
- Check stored items. If several queens appear in the same room, look at what is stored nearby, such as boxes, curtains or the loft hatch above, as that is likely where they were sheltering.
Is there a nest in the loft?
Not an active one. Wasp nests are not active through the winter, and an old nest is never reused. Finding an empty papery nest in the loft in winter tells you wasps nested there last summer, and that the spot may suit another queen next year. It is not a problem in itself. Our guide to late and empty wasp nests explains when one is worth taking down.
Getting ahead of next season
The useful time to act is spring, when the surviving queens wake and choose a nest site. Each one builds a small nest on her own, and a nest found at that stage, around the size of a golf ball, is far easier to deal with than one found in August. In winter, while there is no activity, it is a good time to seal gaps under roof tiles, at the eaves and around pipes, and to fit mesh over air bricks.
Our guides to spotting queen wasps in spring and how a nest starts cover what to look out for.
When to call us
A single queen indoors in winter does not need a pest controller. Call us if wasps keep appearing in numbers, if you are not sure they are wasps, or, from spring onwards, if you see wasps flying regularly in and out of the same spot. Our wasp nest treatment page explains how we deal with nests.