Also called the two-node ants, pavement ants are small, measuring around 2.5 to 3 mm (1/8 inches), with blackish brown bodies and light brown legs, and have two segments (nodes) between the thorax and abdomen. Workers are wingless; queens and males are the only ones who have wings, although they lose them shortly after mating. Just like Pharaoh ants, pavement ants have antennae with 12 segments and 3-segmented clubs. Females have two small spines at the end of their thorax, while males have none on their back. A distinguished feature is the series of fine parallel grooves running from the front to the end of their bodies and two visible humps. Although they are equipped with a stinger, they cannot use it to penetrate the human skin, and so they pose no direct threat to people.
Pavement ant colonies are polygyne, meaning they can hold more than one queen. As a result of having more than one egg layer, each of which can produce between 4 and 50 eggs per day, colonies grow large very quickly. Pavement ants use chemical signals to communicate with each other, especially when they need help foraging. What they do is wipe their gasters (the bulbous posterior part of their bodies) on the ground as they travel to and fro, allowing other workers to follow the trail to the food and find their way back to the nest without getting lost. They also use polarized light to guide their paths.
Ants feed on subterranean termites, alive or dead insects in the soil, plant juices, and a wide variety of sugary foods and drinks, usually rich in carbohydrates and protein, such as baked goods, grease, butter, seeds, pet food, and meats. In fact, they are not picky and will literally feed on anything humans consume.
In nature, pavement ants will dwell in open fields under stones and debris. In urban settings, they can be found nesting under pavement tiles, sidewalks, driveways, under building foundations, as well as under patios. A colony doesn’t usually have more than one queen, and large nests can hold between 10,000 and 30,000 workers who live for several years.
Rarely are their nests located indoors, behind baseboards, in wall voids, under floors and insulation, and generally close to a heat and moisture source. Their colonies are usually located outdoors, and their preferred locations include:
When the nest is located outdoors, it can be easily identified by the mound of soil at the top. However, inside the house, there aren’t too many telltale signs that you are dealing with a pavement ant infestation – sometimes, months can go by without seeing one. As in the case of Pharaoh ants, the most obvious sign of a pavement ant infestation are the workers themselves out foraging – most likely found in the kitchen and pantry in large numbers – but other indicators may be:
Management and effective control of pavement ants are much simplified once you can identify ants’ access points, travel routes, and food and water sources. As with other species of house ants, there is no point in spraying pesticides on worker pavement ants – not only will this not have any impact on the nest, but new workers will immediately be sent to replace the dead ones. In fact, spraying insecticide will prompt ants to move the nest and avoid the treated area completely.
Before choosing an adequate treatment method, a thorough inspection must be carried out by pest professionals, both inside and outside the house, to identify all main and satellite nests. Finding and sealing their points of access will discourage ants from entering your property, followed by the proper use of ant baits that, once ingested and spread throughout the colony, will eliminate the queen and prevent immature ants from developing into adults.
Proper placement is key to obtaining control through the use of baits. Pest control professionals should place baits containing boric acid, hydramethylnon, and other toxicants in areas where intense foraging activity has been observed, but out of children’s and pets’ reach. These substances have a delayed effect, meaning that they don’t kill worker ants immediately, allowing them to return to the nest and share the baiting materials with the entire colony. Permanent solutions for pavement ant infestations require placing several bait stations with attractive bait to last for several weeks (fresh and plenty to satisfy the entire colony).
After a specialized pest control company applies chemical treatments and ant baits to eliminate current infestations, you can follow these tips to ensure pavement ants will not trespass on your property ever again: