Side by side
- Black garden ant: workers roughly 3–5mm, dark brown to black and glossy
- Pharaoh ant: workers about 2mm, pale yellow to amber, often with a darker tip to the abdomen
- Black garden ant: nests outdoors in soil, under paving and at the foot of walls
- Pharaoh ant: nests indoors in warm, hidden places and cannot live outside through a British winter
- Black garden ant: a single queen in each colony
- Pharaoh ant: many queens, often spread across several nest sites
Size is easiest to judge against something familiar, such as a coin or a ruler marked in millimetres.
Where you will find each one
Garden ants come in from outside, mostly in spring and summer, and trail towards kitchens near the back door. Pharaoh ants can turn up anywhere warm indoors at any time of year: along heating pipes, behind kitchen units and bath panels, in wall voids, around light fittings and inside appliances. They are a known problem in heated buildings such as large blocks of flats and hospitals. In a house they are uncommon, but they can arrive with furniture, boxes or luggage from an affected building.
Spotting a Pharaoh ant
They are so small that a trail can look like a faint moving thread. Zoom in with a phone camera or a magnifying glass: the body is pale and slightly see-through rather than black. The shape is much the same as a garden ant, so colour and size are the quickest check. They go for sweet and fatty foods, and also for moisture around sinks, baths and plant saucers. Pharaoh ants mate inside the nest rather than in outdoor swarms, so a summer flight of winged ants points to a garden species.
Why spraying Pharaoh ants backfires
When a Pharaoh ant colony is disturbed, for example by repellent sprays, groups of workers carry brood away with one or more of the queens and set up new nests nearby. This is known as budding. One colony becomes several, often in neighbouring rooms or flats, and each is harder to reach than the original. So do not spray, dust or put repellents down for small pale ants.
Flats and heated blocks
Pharaoh ants travel through service ducts, pipe runs and wall voids that link the homes in a block. In large blocks, such as those in Wembley, one flat may be only part of the picture. Tell your landlord or managing agent, and neighbours if you can, and report sightings in communal areas such as bin rooms. Other insects move between flats in similar ways, as how cockroaches spread between flats shows.
Hygiene
Garden ants on a worktop are mainly a nuisance. Pharaoh ants are taken more seriously in hospitals because they can carry bacteria onto clean surfaces and into supplies. At home, throw away food they have got into and keep the rest sealed. If you have a health concern, speak to a pharmacist or GP.
Other tiny insects in the kitchen
Small brown insects that run fast and look flat, rather than having an ant's pinched waist, may be young cockroaches; compare with German vs Oriental cockroaches. Garden ants that seem to come out of a wall rather than the garden are covered in can ants nest inside walls.
What to do before anyone treats
- Do not spray or put down shop-bought ant products
- Take a close-up photo of an ant beside a coin or a ruler
- Note which rooms, what time of year, and whether the ants ever head outside
- Keep food in sealed containers in the meantime
If they are clearly black garden ants coming from the garden, finding the nest is the next step. Either way, book ant control and send your photo and notes. Ant control in Brent is £190 for a flat and £220 for a house.
