You have been experiencing small, brown ants in your town house since the weather has turned cold. You can't tell where the are coming from but you see them on the floor and in the cupboards. You find them especially in the peanut butter and the cat's dry pet food.
QUESTIONS
1. What kind of ants are they?
They are pavement ants. They are about 1/8 inch long and reddish brown. Under magnification, you can distinguish pavement ants as they have two nodes on their petiole (the waist between the abdomen and the thorax), a pair of small spines on the back of their thorax, and a series of furrows on their head. Pavement ants prefer to feed on meats, cheeses, and greasy foods.
2. Where are they nesting?
Pavement ants nest in the soil, under objects, such as stones, bricks, sidewalks, and driveways. When they are found indoors during the winter, they almost always are nesting under the concrete slab construction of homes. The warmth from the buildings helps keep nests active during winter. Workers move up through cracks into the home to forage for food and water. Ironically, many people that see pavement ants during winter do not see them in the summer when the ants are more likely to forage for food outdoors.
3. Will they cause any damage to my home?
It is not unusual to see piles of soil and bits of concrete on the floor through the nest-building activities of pavement ants. This debris usually indicates the area where pavement ants are coming up through concrete. Despite this, pavement ants are not damaging your foundation or any other area of your home. They are also never in wood like carpenter ants. Their presence is a nuisance but not a structural threat to your home.
4. What is the best method to get rid of them?
If you can determine where the pavement ants are entering through the slab (look for small piles of dirt), you can try to seal the cracks in the concrete to prevent them from getting into your home. If this isn't possible, the best long-term control is to bait them. You can find baits anywhere that sells insecticides (e.g. hardware stores, home improvement stores, retail variety stores etc.). Buy one that is effective against grease-feeding ants. You can also hire a professional pest control service. They have the experience and access to effective baits to successfully eliminate pavement ants. If there is a large enough crack, they may also dust through the opening to control them. Don't spray your pavement ants. You may kill a few foraging workers but it has no effect on the colony plus it interferes with any baiting you try.
