- Pavement ants often attack termites living in the ground.
- Two colonies placed close together may often attack each other, and workers may be seen in the thousands battling on sidewalks and driveways during early spring.
- A single nest can hold up to 30,000 workers.
- Pavement ants use a chemical trail to a food source to recruit nest mates.
- During summer, ants dig up the sand between pavement tiles in order to vent their nests, which is where they get their name.
- They sometimes collect seeds from plants and accidentally bury them inside their nest.
- They capture insects called planthoppers and carry them inside their nests where they begin “milking” them for a substance these produce called honeydew.
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.
Diet, Behavior & Habits
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:
- In sidewalk cracks
- Under stones
- Under concrete slabs, logs, bricks, and boards
- Under mulch in landscaped beds
- Under driveways
- Close to building foundations
Signs of Infestation
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:
- Small piles of excavated material such as sand and soil found outside their nesting sites
- Dead bodies of pavement ant workers
- The presence of swarmers (winged pavement ants)
- The presence of a large number of workers in wall voids, beneath toilets, under insulation in attic and crawlspaces, above false ceilings, behind water heaters and pipes
Management & Control
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:
- Always practice good sanitation.
- Carry out the necessary repairs for leaking pipes and faucets and clear out any bodies of standing water.
- Trim vines, branches, shrubs, and other vegetation that touches the structure of your house and can be used as ant highways to get inside the house.
- You can significantly reduce the chances of an infestation by limiting food consumption to a particular area of the house that is regularly cleaned.
- Cover cracks, crevices, and holes in windows, door frames, windowsills, in the foundation of the building, along baseboards, and in any other areas that are used as access points by ants (caulk is a suitable material).
- If you have piled wood, stones, bricks, mulch, leaf litter, and debris lying on your property, chances for ants to see them as potential homes are high. Either remove them completely or take them as far from the house as possible.
- Keep food in containers with tight-fitting lids.
- Clean spills and crumbs regularly.