Flying ants in the house: what they are and what to do

Why they suddenly appear

Once a colony is mature, it produces winged reproductive ants. They leave the nest together, often triggered by warm, humid, still weather, so that mating flights across a whole area line up. That's why they seem to arrive all at once and are gone within a day or two.

Winged ants are a sign of a healthy, established colony. They don't mean a new infestation has just started.

Flying ant or termite?

They look similar at a glance and the difference matters, because the treatments are completely different. Three features separate them:

• Waist: ants have a clearly pinched waist; termites are straight-sided
• Antennae: ants have elbowed antennae; termites' are straight and beaded
• Wings: ant wings are unequal, with the front pair longer; termite wings are four of equal size

What to do on the day

Vacuum them up and empty the vacuum outside. Spraying the swarm kills the few you can see and does nothing to the colony they came from.

Note where they're emerging from. Flying ants coming out of a window frame, skirting, light fitting or vent point to a nest in the wall cavity, ceiling or subfloor. A swarm rising from paving or lawn outside is far less of a concern.

When to get it looked at

If they keep appearing indoors over several days, are emerging from the same spot inside the building, or you aren't sure whether they're ants or termites, it's worth having them identified. Keep a few in a jar or take a clear photo - it saves a lot of guessing.