Tetramorium caespitum is widely known as the pavement ant, a name it earned from its common habit of nesting in and under cracks in paved surfaces. This ant species is one of the most frequently encountered in urban and suburban environments across North America and Europe. Its widespread presence makes it a familiar sight for many, often found foraging in yards, sidewalks, and even inside homes.
Identifying Pavement Ants
Pavement ants are relatively small insects, typically measuring about 2.5 to 4 millimeters in length. Their bodies range in color from dark brown to blackish, often with paler legs and antennae. A distinguishing physical feature is the presence of parallel grooves or lines along their head and thorax.
These ants primarily establish their nests in or beneath cracks in concrete and asphalt, such as sidewalks, driveways, and building foundations. They also construct nests under stones, logs, and even inside structures within walls or under floors. While native to Europe, Tetramorium caespitum has become a widespread invasive species across North America, adapting well to diverse temperate climates.
Pavement Ant Behavior and Diet
Pavement ants exhibit an omnivorous diet, consuming other insects, seeds, and honeydew, a sugary liquid produced by aphids. When foraging, they are also readily attracted to human foods, showing a particular preference for sweets, meats, and greasy items.
A notable behavioral characteristic of pavement ants is their territorial nature, which often manifests as large-scale “sidewalk wars.” These conflicts involve numerous ants from different colonies engaging in non-lethal battles for foraging territory.
During these skirmishes, ants grapple with each other in dense masses. Such battles can involve hundreds or even thousands of individuals, creating a swirling mass of combatants on the pavement surface. These engagements are a regular occurrence during warmer months, representing a significant aspect of their colony interactions and resource defense. The ants primarily use their mandibles to grapple, often dragging opponents away rather than causing fatal injuries.
Pavement Ants as Household Pests
While pavement ants possess a stinger, stings are rare and typically not medically significant. Their primary pest status arises from their tendency to forage for food inside residential and commercial buildings. They commonly enter structures through small cracks in foundations, gaps around windows, or other tiny openings.
Once inside, these ants often form visible trails as they move between their nest and discovered food sources, frequently leading to kitchens and pantries. Managing their presence indoors involves several non-chemical approaches. Sealing potential entry points around a building’s perimeter can help prevent their access. Maintaining a clean environment by promptly cleaning up food crumbs and spills also reduces attractive food sources. Wiping away existing pheromone trails with soapy water can disrupt their foraging routes, making it harder for other ants to follow.