Pavement Ant Control: Protect Your Home
Scientific Classification: Tetramorium caespitum
Known for nesting beside or underneath sidewalks, driveways and foundations, the pavement ant is a considerable pest found throughout the Mid-Atlantic region. One of most commonly encountered ant species in commercial buildings, pavement ants enter structures through expansion joints and cracks in the slab to search for readily available sources of food and heat. The insects are found in various soil types and prefer to nest in areas with little to no vegetation, making urban settings ideal. Pavement ants typically form large colonies of up to 10,000 workers.
What Do They Look Like?
Size: Worker ants range from 3 to 4 mm in length, while alates or winged fertile workers may be twice that size. The queen is typically 6 mm in length at minimum.
Color: Pavement ants typically appear light to dark brown in color. Some are even darker and almost black.
Characteristics: The body of the pavement ant consists of a head, a thorax and an abdomen. A pedicel connects the thorax to the abdomen and has two segments. The thorax features a pair of spines that project upwards and backwards, though male alates typically lack this physical characteristic. In the last abdominal segment, the ant species possesses a stinger. Pavement ants are also identifiable by the parallel furrows or lines present on both the head and thorax.
The pavement ant is found throughout the United States, as populations have been identified in New England, the Midwest, and as far west as California and Washington. As urban pests, pavement ants are also found throughout commercial and residential areas in the Mid-Atlantic states.
What Do They Eat?
Pavement ants are omnivorous insects that feed on various plants, dead and live arthropods, sugars, nectar and the syrup of most fruits. In human domiciles, the foraging insects seek out and feed on both sweet and greasy foods.
Male and female pavement ants each possess wings prior to mating. After the mating process completes, the female queens lose their wings while the males typically die. Queens lay up to 40 eggs per day. Fertilized eggs produce either workers or other queens, while unfertilized eggs become males. Grub-like larvae hatch from the eggs and undergo three larval instars before becoming adults. In pavement ant colonies, multiple queens typically take responsibility for all egg-laying, while workers tend to the young throughout the life cycle. With more than one queen, nests tend to grow rapidly. Workers may live for up to five years, while queens generally live much longer.
- Look for excavated soil outside of nest entrances near sidewalks, building foundations, patios, and driveways.
- May notice swarms of pavement ants indoors.
- Look for pavement around baseboards, expansion joints, and floor registers in office buildings.
Problems Caused by Pavement Ants
The most common problems caused by pavement ants stem from the nesting behaviors of the pests. Pavement ants typically build their nests under foundations, roads, and walkways, which may sink or resettle and cause structural damage over time. The pests also forage and swarm in buildings and homes, causing large populations to grow if left unchecked. Additionally, the pavement ant may sting when handled or alarmed, although this is rare.
Signs of Infestation
When excavating nests, the pavement ant may leave piles of soil and dirt at the entrance, which creates identifiable mounds near sidewalks and other paved areas. Though nocturnal by nature, foraging pavement ants may leave trails to and from food sources. During mating season, the swarming insects become highly noticeable and often reveal the existence of a nearby pavement ant infestation.
To prevent pavement ant infestations, find and seal all areas of ingress around the home. Sealing gaps and cracks in exterior walls may help deter the insects from moving inside. Keeping the house clean and free of dropped food also proves beneficial. For outdoor protection, sweeping certain prescribed pest solutions into cracks and mounds may prevent nests from growing or ants from returning to the site.
Tips for Removal from Home
Traps and baits may be effective in controlling a pavement ant infestation. However, due to the large size of the typical pavement ant colony, some home baits may not work as effectively since the poison acts slowly and may not distribute efficiently. For large infestations of pavement ants, contacting a certified and trained pest control professional is the most effective way to remove the pests.
Outdoors, pavement ants are ground-nesting ants. In nature they nest under rocks and logs. In residential neighborhoods they make nests under sidewalks, driveways, and slabs of homes. They enter homes through cracks in walls and foundations.
When pavement ants move indoors, they often nest inside of walls. In cold weather they have been found nesting near water heaters and furnaces. The workers forage for food in trails that can extend 25 or 30 feet from the nest.
If pavement ants are becoming a problem, start by following the trail of workers. It is often possible to follow the trail back to the nest. If the trail leads outdoors, it may be possible to drench the nest with liquid insecticide and eliminate the colony. Follow the label directions for mixing and applying insecticide.
If the trail leads under a baseboard, it may be possible to drill tiny holes above the baseboard. Inject insecticide dust into the void inside the wall. Products that contain boric acid or diatomaceous earth may be slower acting than other products, but they will last the longest.
Ant bait is a very effective tool against pavement ants. Liquid or gel bait will be accepted quickly. Place the bait near the trail so the workers will find it. Make sure children and pets cannot reach the bait. Keep the bait station filled with fresh bait until all the ant activity has stopped.
An insecticide barrier around the outside perimeter of the home can help prevent pavement ants from invading the home. Because of sunshine and rain, the barrier will have to be re-applied periodically. Ant control takes time and requires patience. Many homeowners find it easier to let a pest control professional take care of these pests.