Flying ants in the house: is it an infestation?
Usually not. Flying ants are a mating flight that tends to be over within a day or two. What matters is whether they came in from outside or came out of a nest inside.
A room full of winged ants on a warm evening looks like an invasion, but it is almost always a mating flight. Winged ants leave their nest all at once, often on warm, humid days, to mate and start new nests elsewhere. The flight itself tends to be over within a day or two. The real question is where they came from.
In from outside, or out from inside?
- In from outside looks like this: they gather near open windows, doors and lights, and you can see plenty of flying ants outdoors on the same day. Annoying, but no nest indoors.
- Out from inside looks like this: they come out of one spot in the room, such as a gap in the skirting, a crack in the floor or around a fireplace, even with the windows shut. The nest is in the building, inside a wall or under the floor.
What to do tonight
- Close the windows and turn off lights near open doors. Lights draw them in.
- Vacuum them up. It is quicker than anything else and leaves nothing behind. Empty the bag or bin outside.
- Watch where they come from. If they keep appearing from one gap, mark it or take a photo.
- Skip the fly spray. It kills the ones in the air but does nothing to a nest, and it leaves residue on surfaces in the room.
- Wipe the spot with soapy water once the swarm has settled.
If they came out of the house
Watch the same spot over the next few days. If wingless worker ants start trailing from it to food, the nest is active and close by. That is when bait comes in: enclosed ant bait stations on the trail, so the workers carry it back to the nest. Our page on ants coming out of a skirting board has the plan. Follow the label and keep stations out of reach of children and pets.
One thing confuses a lot of people: bait clears the workers, but the winged ants ignore it. They are not looking for food, they are leaving to mate. So vacuum the winged ones and keep baiting the workers. If the ants walk past the bait too, see ants that ignore bait.
Once the spot has been quiet for a while, seal the gap. Our guide to sealing gaps shows how.
Ant or termite?
Termites swarm too, and in some parts of the world they do real damage to buildings. Catch one in a clear pot and look closely.
- Ant: a pinched, narrow waist, antennae bent like an elbow, front wings longer than the back ones.
- Termite: a thick waist with no pinch, straight antennae, all four wings about the same length.
Piles of dropped wings on a windowsill can come from either. If yours look like termites, or termites are known where you live, ask a professional to inspect. Do not break into walls to look yourself.
Kids and pets: vacuuming is the safest way to clear a swarm. If you use bait afterwards, choose enclosed stations, follow the label, and keep them up high or locked away from children and pets.
When it is worth a professional
- Swarms come out of the same indoor spot again and again.
- The wood near the spot is damp, soft or crumbling. See carpenter ants.
- They might be termites.
- Workers keep trailing after a few weeks of bait.
Everything else about ants, from trails to baits, is in the ant guide.
More questions
Will they go away on their own?
The flight usually does, within a day or two. If they came out of a nest inside, the nest stays, so watch for worker ants afterwards.
Do flying ants bite?
Some can nip, and some kinds sting. Vacuum them rather than handle them.
Why did they all appear on the same day?
Warm, humid weather sets off mating flights, so many nests in an area often fly at once.
They came from outside. Do I need to do anything else?
Keep windows shut or screened during the flight and vacuum the ones that got in. There is no nest indoors to treat.
If a product label ever says something different from this page, follow the label. Safety and labels