# Pavement ant (Tetramorium immigrans) > Small, dark brown ants that nest under pavement, sidewalks and foundations and commonly forage indoors for sweets and proteins. Source: https://insectscanner.com/species/pavement-ant/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Pavement ants do not have dangerous venom. Workers can pinch with their mandibles and have a tiny sting that rarely penetrates human skin, causing at most a brief, mild irritation for most people. Bites and stings are rarely medically significant. Clean the area if skin is broken and seek medical care if an allergic reaction occurs. **Pets:** Generally not dangerous to pets. Large numbers can annoy pets or occasionally get into pet food. If pets have allergic sensitivity, watch for itching or swelling; consult a veterinarian if severe. ## Quick facts - Scientific name: Tetramorium immigrans - Also called: Immigrant pavement ant - Order: Hymenoptera (Ants, bees, wasps) - Family: Formicidae (Ants) - Size: Workers 2.5-4 mm; queens 6-8 mm - Colours: Brown, Dark brown, Black - Habitat: Urban and suburban areas: cracks in pavement and sidewalks, under stones, curbs, building foundations, lawns and occasionally inside buildings. - Range: Native to Europe and parts of Asia; introduced and common across North America and other temperate regions worldwide. - Active: Spring through fall (most active during warm months); workers forage day and night depending on temperature. - Lifespan: Workers live months to about a year; queens can live several years (often multiple years in established colonies). - Effect on plants: Harmless - Pest: yes ## Overview Tetramorium immigrans, commonly called the pavement ant, is a small, ground‑nesting ant originally from Eurasia and now widespread in temperate urban and suburban areas worldwide. They build colonies in cracks in pavement, under stones, under building foundations and in lawns. Pavement ants forage widely for sugary and protein foods and are a frequent nuisance pest in homes, restaurants and other buildings. Colonies vary in size from a few hundred to many thousand workers; some populations form single‑queen (monogyne) colonies, while others can have multiple queens. They are most active in warm months and can be seen forming characteristic trails from nest entrances to food sources on sidewalks and along foundations. ## How to identify it Workers are small (about 2.5-4 mm), uniformly brown to dark brown with a slightly darker head and gaster (abdomen). The head and thorax have fine sculpturing (parallel ridges) and the mesosoma (middle section) has two short spines near the rear. The petiole (waist) has two distinct nodes. Antennae have 12 segments with a three‑segmented club. Queens are larger (6-8 mm) and winged or have wing scars if mated. - Small workers 2.5-4 mm, uniformly brown to dark brown with a slightly darker gaster. - Two petiole nodes (two-segmented waist) and two short spines on the rear of the mesosoma. - Head and thorax show fine parallel sculpturing; antennae with 12 segments and a 3-segmented club. - Nests in cracks in pavement, along foundations and under stones; look for worker trails at nest entrances. ## Lookalikes - **Tetramorium caespitum (old-world pavement ant)** (Tetramorium caespitum): Very similar and historically confused with T. immigrans; microscopic examination of sculpturing and genetic tests are used by specialists. In many regions T. immigrans is the introduced taxon. - **Little black ant** (Monomorium minimum): Smaller (about 1.5-2 mm), shiny jet black and smooth, lacking the ridged sculpturing and the pair of spines at the rear of the thorax seen in pavement ants. - **Yellow‑brown garden ant** (Lasius neoniger): Larger, smoother body with different petiole shape and lacking the two mesosoma spines; usually found in lawns rather than pavement cracks. ## Life cycle - **Egg:** Tiny, oval, white eggs laid by the queen; eggs hatch into larvae in about 1-2 weeks depending on temperature and colony nutrition. - **Larva:** Legless, grub‑like larvae that are fed and cared for by workers. Larval development takes days to weeks depending on resources and temperature. - **Pupa:** Pupae may be enclosed in a thin cocoon; during this stage the ant transforms into the adult form. - **Adult:** Workers (sterile females) forage, care for brood and nest; reproductives (winged males and queens) leave for mating flights, after which queens start new colonies or join existing ones. ## Diet and predators - Young eat: Fed by workers on regurgitated liquids, sugars and protein-rich prey or insect parts. - Adults eat: Omnivorous: collect sweets (nectar, honeydew, sugary foods), proteins (insects, meats), and oils; in buildings they forage for crumbs, spilled drinks and pet food. - Predators of the young: Predators include spiders, other ant species, small mammals and parasitoids. - Predators of adults: Birds, larger ants, spiders, centipedes and insectivorous mammals prey on workers. ## Effect on plants and gardens Pavement ants do not feed on living plants and are not major agricultural pests. They can tend aphids or other sap‑feeding insects, indirectly promoting plant pests in small cases. ### How to get rid of it Use a combination of sanitation (remove food sources, store food in sealed containers), exclusion (seal cracks and entry points around foundations and windows), and baits (sugar or protein baits with slow‑acting insecticides such as borax or commercial ant baits) placed along trails. For outdoor nests: pouring boiling water into visible nest cracks can kill some workers and queens but may not eliminate large colonies. For heavy or persistent infestations, consider a licensed pest control professional. Avoid spraying random contact insecticides indoors as they can repel workers and cause colonies to relocate. ## Where and when to find it Look for worker trails on sidewalks, curbs, driveways and along building foundations; nests in cracks in pavement, under stones, under concrete slabs and in lawns. Inside buildings they appear along baseboards, in kitchens and near food sources. - Best time: Spring through early fall; daytime in warm weather but may forage at night if hot. - Tips: Follow worker trails back to their entry point to locate nests or where to place baits. Photograph ants with a macro lens or phone close to the ground; use indirect light to show body sculpturing. ## Fun facts - Pavement ants often create long foraging trails between nest entrances and food sources that can be seen on sidewalks and curbs. - They commonly nest under pavement and can exploit tiny cracks—hence the common name. - Pavement ant colonies can be flexible in social structure: some populations have a single queen while others have multiple queens, which affects colony size and behavior. ## Frequently asked questions ### Do pavement ants bite? Workers can pinch with their mandibles and have a tiny sting that rarely penetrates skin. Any irritation is brief and not dangerous for most people. ### Are pavement ants harmful to my house? They are mostly a nuisance: they forage for food indoors and can contaminate food. They rarely damage structures but may nest in wall voids or insulation in some cases. ### Why are pavement ants in my house? They are attracted to accessible food (sugary and protein items), crumbs, spills and pet food. Indoor access is often through gaps around foundations, doors or utility lines. ### How can I get rid of pavement ants? Combine sanitation and exclusion with baits placed on trails. Use slow‑acting sugar or protein baits (borax or commercial ant baits) so workers carry poison back to the colony. For large infestations, hire a pest control professional. ### Will crushing a trail of pavement ants stop them? Crushing a few ants only removes workers and may scatter the trail pheromones. It does not remove the colony; baiting and nest treatment are more effective. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/569552), [Wikipedia](https://en.wikipedia.org/wiki/Tetramorium_immigrans). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.