Several different types of ants are commonly seen around the home. Of the more than 12,000 different species, only a fairly small fraction poses problems for homeowners. These common species range from fairly large and destructive carpenter ants (Camponotus spp.) to the small and relatively innocuous pavement ants (Tetramorium spp,).
The pavement ant is one of the smaller ant species, at 1/10 to 1/6 inch long. It is one of the most common species in the United States, found in all 50 states. The pavement ant is brownish-black with pale-colored legs. With a magnifying glass or microscope, you can see that it has two spines between its body parts and tiny stiff hairs covering its body.
These are the ants you frequently see colonizing out of the cracks in sidewalks, but it's not uncommon to also see them crawling across the kitchen floor in search of grease spots, trailing across your picnic blanket, or following the smell of BBQ on your patio.
There is usually no reason to worry about outdoor colonies of pavement ants, but when this tiny ant decides to establish an indoor colony, it becomes a nuisance you'll need to deal with.
3 Ways to Get Rid of Pavement Ants
Keep Your Home Spotless
Ants will leave your home if there is no food for them to eat, and in the case of pavement ants, eliminating meat and grease scraps from floors, countertops, and garbage collection areas will usually remove their reason for being in your home. Even a single splatter of bacon grease on a kitchen floor provides pavement ants with a feast, so daily cleaning of all surfaces is the best way to chase pavement ants out of your home.
Use Ant Baits
Whether the colony is outdoors or hidden somewhere in your house, baiting ants is usually the most effective strategy. Placing bait stations along the observed trail where you see ants traveling will cause the workers to find the bait and carry it back to the nest, where the queen (or queens) will feed on it.
This will soon eliminate both the queens and future populations. Any number of effective chemical ant baits are available, but a safe homemade ant bait can be made by mixing household borax with honey or syrup.
Of the commercial ant baits, those containing methoprene and pyriproxyfen are regarded as relatively safe and low in toxicity in comparison to other chemicals, such as hydramethylnon, various neonicotinoids, avermectin, fipronil, metaflumizone, and fenoxycarb, some of which are considered probable carcinogens.
Use an Insecticide Spray
If you do happen to trace the ant trail back to an outdoor, below-ground nest, drenching the nest with an approved insecticide spray can also be effective at eliminating the population. But spraying individual pavement ants as you see them is rarely very effective because this kills only the workers you can see; more will quickly be sent out from the colony to forage.
What Causes Pavement Ants?
Like other species of ants, the Tetramorium species may enter homes in large numbers in search of food. They will eat almost anything that humans eat, and some things we don't, such as live and dead insects. But for these species, the real preference is for meats and grease, and pavement ants will very likely find a way into any home where this food source is present on floors, countertops, or garbage collection areas.
How to Prevent Pavement Ants
Keeping food sources sealed and kitchens spotlessly clean is one of the best ways to discourage infestations from any ant species, including the pavement ant. Sealing cracks and gaps in siding and foundations may help deny ants entry points into the home, but pavement ants are so tiny that unless you also maintain scrupulous cleanliness, they will probably find a way in.
Ants vs. Termites
In the spring and early summer, swarms of winged pavement ants will fly to mate and reproduce. These winged ants can be confused with termites because termites also swarm at this time of the year. But ants can be distinguished from termites by several characteristics:
Wings: The pavement ant's front wings are longer than its back wings; termite wings are of equal length.
Body: Ants have a narrow waist; the termite's thick waist makes it look like it has only one body part.
Antennae: Ants' antennae are elbowed; termites' are straight.
Pavement Ants vs. Grease Ants
Another common indoor ant is the grease ant (Solenopsis spp.) which is so named because of its fondness for meat greases. These ants are also very small, at 1/32 to 1/8 inch long, but are distinguished from pavement ants by their yellow or light brown color. By contrast, pavement ants are usually slightly larger and are dark brown or black in color.
Grease ants are harder to control than pavement ants since they are not typically attracted to the sweet baits used to control other ants. However, you can effectively bait grease ants by mixing borax with meat grease and placing it along ant trails.
How Do I Identify an Outdoor Colony of Pavement Ants?
When a pavement ant colony is outdoors, it can be easily identified by the small cone-shaped mound of soil that usually sits atop the nest. This ant often builds its colony beneath concrete cracks in driveways and sidewalks, and beneath rocks and logs. It tunnels into the soil to dig out space for its colony, pushing the dirt up through the top of its nest, creating the trademark sandhill-like mounds. The only real problem this causes is that paved surfaces can sometimes be undermined. A sand-set patio, for example, may settle and sink when ants remove enough sand from beneath the brick pavers. Resetting loose-set pavers, though, is usually rather easy.
A typical colony will have 3,000 to 5,000 ants, although there can be as many as 30,000 ants in a single colony. There can be more than one queen in each colony, and since it is the queen that produces all the offspring, there can be a lot of baby ants in one pavement colony.
Although you may see pavement ants during the day, they are most active at night. If you happen to have more than one colony on your property or another one nearby in the neighborhood—and you happen to be watching at the right time—you just might witness the unique event of an ant battle or its aftermath. Pavement ant colonies will fight for territory, and these battles can leave hundreds of dead ants on the battlefield.
How Do Pavement Ants Get Into a Home?
Because of their small size, pavement ants can easily get into homes and buildings through tiny cracks, around doors and windows, and beneath spaces under the siding. One of their most common entry points is beneath sliding doors. Like other species, pavement ants can sometimes set up colonies within walls or under flooring, and in woodwork, masonry, or insulation. Although pavement ants do not destroy wood or other building materials, they can be a definite nuisance when large numbers infiltrate a home.
Do Pavement Ants Bite or Sting?
The pavement ant is rarely aggressive, but it can sting when disturbed. Though its sting is generally too weak to penetrate human skin, it can cause allergic reactions or rash in people who are sensitive to the bite.
Do Pavement Ants Carry or Spread Diseases?
Pavement ants (or other ant species, for that matter) are not direct carriers of disease pathogens, in the way that mosquitoes or ticks are. But ants can spread food-borne illnesses on their feet as they move through rotting food material. The risk of this kind of transmission from ants, however, is much less than from mice and other rodents—or even from the common housefly.
Risk Assessment for Carcinogenic Effects. United State Environmental Protection Agency.
Pavement Ant. Penn State Extension.