Types of ants: identify the ant you found

Common household ants

Argentine Ant Linepithema humile The Argentine ant is the most common ant in and around homes in California; its nests are linked into huge multi-queen supercolonies. It is native to Argentina and Brazil. Texas A&M says it was discovered in New Orleans in 1891, is now established in many places in the southern United States, and has been found in Arizona, California, Illinois, Maryland, Missouri, Oregon, Texas and Washington. Odorous House Ant Tapinoma sessile The odorous house ant is a small native ant found across most of the United States that trails into homes for sweets and gives off a strong, rotten odor when crushed. Texas A&M says it ranges from Canada to Mexico but is rarely found in the southwestern deserts. Pavement Ant Tetramorium immigrans The pavement ant is an introduced, soil-nesting ant that lives under sidewalks, slabs and stones. Penn State calls it one of the most commonly encountered house-infesting ants in Pennsylvania and says its range runs from New England to the Midwest and south through the Mid-Atlantic states to Tennessee, with populations in parts of California and Washington. Pharaoh Ant Monomorium pharaonis The Pharaoh ant is a tiny, yellowish ant that nests inside heated buildings and is a serious pest in hospitals, apartments, hotels and food businesses. Texas A&M says it occurs throughout the United States but generally only in heated buildings, because it usually can't survive outdoors all year; it does nest outside in subtropical areas such as Hawaii, Florida and southern Texas. Carpenter Ants Camponotus species Carpenter ants don't eat wood the way termites do; they excavate it to nest, usually starting where wood is damp or decayed, and indoor nests are often satellites of a parent colony outdoors. Minnesota and Clemson extension both stress that they don't eat wood; they tunnel into it to make a nest. Red Imported Fire Ant Solenopsis invicta The red imported fire ant is an aggressive stinging ant that infests most of the southern United States and parts of California, building mounds in open, sunny areas such as lawns, parks and roadsides. USDA APHIS says imported fire ants came from South America, probably in soil on cargo ships, and now infest more than 367 million acres in Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia and Puerto Rico. Acrobat Ants Crematogaster species (e.g., C. lineolata) Acrobat ants are small ants named for the way workers lift their heart-shaped abdomen up and over the rest of the body. Outdoors they live in trees, logs, firewood and under rocks, preferring wood softened by decay or fungi; indoors they favor framing that moisture or earlier insects have already damaged. Tawny Crazy Ant Nylanderia fulva The tawny crazy ant, first called the Rasberry crazy ant, is an invasive ant from South America. It was first reported as a pest near Houston, Texas, in 2002 and is now established in six southern states. Its interconnected nests form huge supercolonies that cover yards and get into electrical equipment. Ghost Ant Tapinoma melanocephalum The ghost ant is a tiny tropical tramp ant whose pale abdomen and legs make it hard to see. It nests indoors and out, forages on set trails and favors sweets, and because each colony is spread over many nests it is hard to eliminate. Little Black Ant Monomorium minimum (iNaturalist files it under Monomorium carbonarium) The little black ant is a tiny native ant that nests outdoors in lawns and under stones, and indoors in woodwork, wall voids and masonry. It is most noticeable when long foraging trails reach food cabinets and pantries. Bigheaded Ant Pheidole megacephala Bigheaded ants are named for the oversized, two-lobed head of their major workers, or soldiers. The invasive Pheidole megacephala is one of the world's 100 worst invasive species and a household and agricultural pest throughout the tropics; the Mississippi Entomological Museum lists it from Florida as an occasional household pest that competes with native ants. Asian Needle Ant Brachyponera chinensis (formerly Pachycondyla chinensis) The Asian needle ant is an introduced stinging ant from Asia, first reported in the United States in the 1930s but recognized as a pest only since 2006. It nests in both disturbed yards and natural forests. Longhorn Crazy Ant Paratrechina longicornis The longhorn crazy ant is a dark, long-legged invasive ant known for fast, erratic running. In a lab comparison of six pest ants, it and the tawny crazy ant swung farthest off marked trails and moved about three times faster than the slowest species. Thief Ant Solenopsis molesta The thief ant is a tiny native ant named for nesting near larger ants and stealing their food, larvae and pupae. Also called the grease ant, it trails indoors to greasy and protein-rich foods and is small enough to get into packaged food. White-Footed Ant Technomyrmex difficilis The white-footed ant is an invasive ant that is now a pest in several parts of the world, including Florida, Hawaii and, since 2019, Texas. It forms huge colonies, forages inside and outside buildings, and is rated among the hardest structure-infesting ants to control. Dark Rover Ant Brachymyrmex patagonicus The dark rover ant is a tiny ant native to Argentina and Paraguay that has become widespread in the southeastern United States and keeps expanding its range. Foraging workers and winged swarmers enter buildings, and colonies sometimes nest inside them. Citronella Ants Lasius species: L. interjectus (larger yellow ant) and L. claviger (smaller yellow ant) Citronella ants are yellow, underground ants named for the lemon or citronella smell they give off when threatened or crushed. They are rarely seen until winged swarmers come up through basement or slab cracks, which often sends homeowners looking for termites. Field Ants Formica species (e.g., F. subsericea, F. integra, F. exsectoides) Field ants are medium to large ants in the genus Formica, among the most common ants in yards. They nest in soil, and in Wisconsin their mounds can reach three to four feet wide, spoiling lawns and making mowing difficult. Pyramid Ants Dorymyrmex species (e.g., D. bureni; older sources use D. pyramicus) Pyramid ants, also called crater ants, are small, fast soil-nesting ants of open, sunny ground with a pyramid-shaped point on top of the thorax. They are best known for the crater of soil around their nest entrance, and they have no sting. Red Harvester Ant Pogonomyrmex barbatus The red harvester ant is a large red ant of the southern Plains and Southwest that gathers seeds and stores them underground. It strips the plants from a circle around its nest entrance, and its sting is intensely painful. Florida Carpenter Ant Camponotus floridanus The Florida carpenter ant, called the bull ant in Florida for its strong bite, is a large two-toned carpenter ant of the Southeast and one of the more common ants found foraging and nesting in and around homes. European Fire Ant (European Red Ant) Myrmica rubra The European fire ant, also called the European red ant, is a very small red ant that aggressively defends its territory and readily stings people, pets and livestock. It is only distantly related to the true fire ants of the southern United States. Southern Fire Ant Solenopsis xyloni The southern fire ant is a native fire ant of the Southwest. It nests in bare, sunny soil, swarms out to bite and sting when its nest is disturbed, and often wanders indoors for food in warm months. Trap-Jaw Ant Odontomachus haematodus Trap-jaw ants walk with their long jaws cocked open like a bear trap and snap them shut at one of the fastest speeds in nature. The species spreading along the Gulf Coast is the two-spined trap-jaw ant, a South American import that stings readily. Elongate Twig Ant (Graceful or Mexican Twig Ant) Pseudomyrmex gracilis The elongate twig ant, also called the graceful or Mexican twig ant, is a large, slender, wasp-like ant that nests in hollow twigs, stems and grasses. It can sting, but a peer-reviewed survey of sting pain rated its sting at the minor end of the scale. Cornfield Ant Lasius neoniger (also called turfgrass or lawn ant); Lasius americanus, formerly L. alienus, shares the name The cornfield ant is a small, light to dark brown ant and one of the most abundant ants in North America. It is the ant behind many of the small crater-shaped soil mounds in thin lawns, along driveways and between paving stones. Winter Ant Prenolepis imparis The winter ant, also called the small honey ant or false honey ant, is a native ant that forages in cold weather, when other ants stay home, and spends the summer underground. It mostly nests outdoors in soil and sometimes trails into houses. Black Imported Fire Ant Solenopsis richteri The black imported fire ant is a South American fire ant that reached Mobile, Alabama, decades before the red imported fire ant. Its range stays limited to northeastern Mississippi, northwestern Alabama and southern Tennessee. Little Fire Ant Wasmannia auropunctata (listed on iNaturalist as Allomerus auropunctatus) The little fire ant is an invasive ant from the American tropics whose sting, the Hawaii Department of Agriculture (HDOA) notes, is out of proportion to its tiny size. It was first found in Hawaii in 1999 and has spread there in plants, logs and green waste. Texas Leafcutter Ant (town ant) Atta texana The Texas leafcutter ant, also called the town ant or parasol ant, cuts leaves to grow the fungus its colony eats. Colonies can reach more than 2 million ants and strip landscape plants, gardens and young pines. Florida Harvester Ant Pogonomyrmex badius Florida harvester ants are the only harvester ants east of the Mississippi River. They nest in deep sand, store seeds underground, and their venom causes intense pain. Compact Carpenter Ant Camponotus planatus The compact carpenter ant is a small tropical carpenter ant that forages by day on exterior walls, trees, shrubs and sidewalks, so people notice it more than night-active carpenter ants. It mainly nests in trees but is becoming more of a structural pest in Florida. Robust Crazy Ant Nylanderia bourbonica The robust crazy ant is a small, very dark ant from the Old World tropics that has been in Florida since at least 1924. It is a nuisance rather than a serious pest: in Florida it is best known for wandering across patios and outdoor eating areas. Velvety Tree Ant Liometopum occidentale, L. luctuosum and L. apiculatum Velvety tree ants are western ants with a brownish-black head, yellowish-red thorax and velvety black abdomen; they nest in trees, bite and give off a rotten-coconut odor when disturbed, and colonies sometimes move into wall voids and insulation. Thatching Ants Formica obscuripes (western thatching ant) and related mound-building Formica Thatching ants are medium to large red-and-black or black ants that build mounds of thatch such as fir needles and grass stems; they are beneficial predators but bite in numbers and spray formic acid when a mound is disturbed. Western harvester ant Pogonomyrmex occidentalis The western harvester ant is a reddish-brown, seed-collecting ant of open western grasslands. Its broad, flat mounds, often covered with small pebbles and surrounded by a wide ring of bare ground, are easy to spot, and workers give very painful stings when the nest is disturbed. Black carpenter ant Camponotus pennsylvanicus The black carpenter ant is a common home invader in the northeastern United States and the most common carpenter ant in Ohio and Nebraska. Its large black workers come indoors looking for food, and colonies can set up satellite nests in moist or rotting wood and foam insulation inside the house.

What to do first

UC IPM's first steps work for any household ant, before you know the species.^[1]

• Wipe up ant trails with soapy water to remove the scent trail, then find where they're getting in and caulk it.^[1]
• Use slow-acting baits, mainly outdoors near trails and nests; workers carry the bait back so the whole colony, including queens, can be killed.^[1]
• Don't spray while baiting. Indoor sprays won't stop more ants from coming in.^[1]
• Offer a little sweet, protein and oily bait and see which the ants prefer; preferences differ by species and season.^[1]

Ant or termite?

Winged ants are often mistaken for winged termites. Ants have a thin, pinched waist, hind wings smaller than the front wings, and elbowed antennae; termites have a broad waist, wings of equal size, and straight antennae. Both lose their wings soon after flying.^[1]

Telling common ants apart

Look at size, color and the number of nodes (bumps) on the waist between the thorax and abdomen.^[1]

A node is the small bump or segment in the narrow waist. One-node ants include carpenter, odorous house, Argentine, field, citronella and crazy ants; two-node ants include pavement, pharaoh, thief, acrobat, big-headed, harvester and fire ants. A hand lens helps: thief and pharaoh ants can need a microscope to tell apart.^{[9][1][4][21][27]}

• Argentine ant: one node, 1/8 inch, dull brown; eats sweets and sometimes protein; nests outdoors in shallow mounds and forms huge linked colonies with many queens.^[1]
• Odorous house ant: one node, 1/8 inch, dark brown to shiny black, with a very strong odor when crushed; nests in soil or debris, or indoors in wall voids and near water pipes or heaters.^[1]
• Carpenter ant: one node, large (workers 1/4 to 1/2 inch), black or red and black; nests in stumps, firewood, fence posts and hollow doors or window frames, leaving sawdust-like frass.^[1]
• Pavement ant: two nodes, 3/16 inch, dark brown to black; eats sweets, protein and grease; nests in lawns or under stones and builds mounds along sidewalks and foundations.^[1]
• Pharaoh ant: two nodes, 1/16 inch, yellow to orange; nests in wall and cabinet voids, behind baseboards and near hot water pipes and heating, and prefers fats and protein.^[1]
• Thief ant: two nodes, 1/32 inch, yellow to light brown; prefers greasy, fatty food.^[1]
• Red imported fire ant: two nodes, reddish with a dark brown abdomen, workers 1/16 to 1/5 inch; nests in mounds with many openings in soil or lawns.^[1]

Small black ants in the kitchen, and "sugar ants"

"Sugar ant" isn't one species. Texas A&M lists it as another name for the pharaoh ant, which is yellow to reddish brown, not black.^[20][24]

Small dark ants that trail across counters include odorous house ants, little black ants, pavement ants or Argentine ants. The little black ant is shiny black and about 1/16 inch; the odorous house ant is brown to black, about 1/10 to 1/8 inch, and smells when crushed; the pavement ant has fine grooves on its head and thorax and two nodes; the Argentine ant is dull brown.^[3][9][2][1]

Longhorn crazy ants are grayish black with very long legs and antennae and run about erratically. White-footed ants, found in South Florida, Hawaii and San Francisco, are black with pale yellow feet.^[19][24][22]

Odorous house ant (Tapinoma sessile)

A native ant found throughout the United States, from Canada to Mexico, though rarely in the southwestern deserts. Missouri Extension calls it the most common home-infesting ant in that state.^[13][2]

• ID: brown to dark brown or shiny black, all workers one size. Minnesota gives about 1/10 inch, Texas A&M and UC IPM 1/8 inch, Missouri 2 to 3 mm. The single node is hidden under the abdomen. Crushed workers smell like rotten coconut or blue cheese.^{[9][13][1][2]}
• Food: sweets, especially honeydew, plus live insects; indoors it will also take meats. Missouri notes it moves indoors in large numbers when rain washes honeydew off plants in spring and fall.^[9][2]
• Nests: shallow, under stones, boards, patio blocks, mulch and plastic sheeting, and indoors in wall voids and under floors near moisture such as pipes, heaters and toilets.^[9][2][13]
• Colony: a few hundred to 10,000 ants, usually with several queens. New colonies form when queens leave with a group of workers, and nests move often.^[13][2]
• Bait: Missouri says they are best managed with sweet baits; Texas A&M suggests sugar- or protein-based baits when the nest can't be reached. Also control aphids and other honeydew producers nearby.^[2][13][9]

Pavement ant (Tetramorium immigrans)

Named for nesting beside and under sidewalks, driveways and foundations. Minnesota lists it as Tetramorium immigrans, formerly called T. caespitum.^[2][9]

• ID: reddish brown to black with lighter legs and antennae, two nodes, a pair of small spines on the back of the thorax, and fine parallel grooves on the head and thorax. Workers are about 1/8 inch (Minnesota), 2 1/2 to 3 mm (Missouri) or 3/16 inch (UC IPM).^[9][2][1]
• Food: almost anything, including meats, pet food, sweets, bread, nuts, grease and insects.^[9][1]
• Nests: in soil under pavement, stones and slab foundations, entering homes through cracks in the concrete; sometimes in wall voids.^[9][2]
• Colony and swarms: one queen per colony. Swarms run May through July, and also in winter when the nest is under a heated slab.^[2][9]
• Pavement ant swarms indoors in spring often come from under baseboards, expansion joints and heat registers; vacuum the winged ants and find the outdoor nest under nearby slabs.^[2]
• Stings: Missouri Extension lists the pavement ant as one of the state's stinging ants.^[2]
• Bait: treat outdoor nests when you can find them; for ants nesting under a heated slab, Minnesota says baiting works best.^[9]

Argentine ant (Linepithema humile)

An introduced ant, native to Argentina and Brazil, found in New Orleans in 1891 and now established across the southern United States and in states including California, Arizona, Oregon and Washington. UC IPM calls it the most common ant in and around California homes and gardens.^[14][1]

• ID: one node, 1/8 inch, light to dull dark brown, all workers the same size.^[1][14]
• Food: sweets, sometimes proteins. Sweet baits attract them all year; protein baits mainly in spring.^[1][14]
• Nests: shallow, just under the soil surface, in moist but not wet spots: under stones, boards and plants, in mulch and along sidewalks, and indoors near water pipes, sinks and potted plants.^[1][14]
• Colony: nests are linked into one supercolony with many queens (Texas A&M: hundreds). Ants from different nests don't fight, and in fall colonies often merge to overwinter. The Mississippi Entomological Museum notes these huge supercolonies harm native biodiversity.^[1][14][12]
• Bait: slow-acting sweet liquid baits in stations along trails. Texas A&M notes that when colonies are wiped out of a building, new ones quickly move in, so expect to keep baiting.^[14][1]

Carpenter ants (black carpenter ant and relatives)

The biggest ants most people see indoors. Texas A&M says the black carpenter ant, Camponotus pennsylvanicus, is the species homeowners meet most, from the Atlantic coast to the Rocky Mountains.^[15][9]

• ID: one node, an evenly rounded back when seen from the side, and a ring of hairs at the tip of the abdomen. Black or black and red. Workers come in two sizes, about 1/4 to 1/2 inch; winged queens can be up to 3/4 inch. The black carpenter ant is dull black all over with long yellowish hairs on the abdomen.^[15][9][1]
• Food: honeydew from aphids and scales, other insects, meat and sweets. They don't eat wood; they chew it out to make galleries.^[15][9][11]
• Nests: moist or decaying wood in trees, stumps, firewood and landscape timbers; in buildings, wood softened by leaks, hollow doors, attic insulation and voids around windows. Galleries look clean, as if sandpapered, unlike termite tunnels packed with soil. Look for sawdust-like frass.^[9][15][1]
• Colony: the parent nest is usually outdoors, and an indoor nest is often a satellite tied to a water leak. A black carpenter ant colony has one queen and may reach 15,000 workers; it grows slowly, with only about 10 to 15 workers the first year.^[15]
• Bites: they don't sting, but they bite and can spray formic acid into the wound, which hurts.^[15]
• Swarms: April through June, sometimes indoors in late winter on warm, sunny days.^[9]
• Control: follow workers at night, just after sunset, to find the nest, then treat it directly and fix the moisture problem. Baits can help where ants are active; Minnesota says control usually needs a professional.^[9][15][11]

Florida carpenter ant (Camponotus floridanus)

A Southeast carpenter ant that Texas A&M calls one of the most serious structural pests in Florida and the extreme Southeast. The Mississippi Entomological Museum lists it as a structural and nuisance pest from North Carolina to Florida and west along the coast, mostly in sandy coastal areas.^[15][12]

• ID: yellowish red to red head, thorax and waist with a black abdomen, covered in long yellowish hairs. Workers range from 1/5 to 1/2 inch.^[15]
• Bites: workers bite hard, which is why Floridians call them "bull dog" or "bull ants". Colonies may hold up to 8,000 ants.^[15]
• Control: as for other carpenter ants, find the parent nest and any satellite nests, fix leaks and replace damaged wood, and trim branches that touch the house.^[15]

Pharaoh ant (Monomorium pharaonis)

A tiny tropical ant spread worldwide by commerce. In northern states it lives only in heated buildings; in subtropical areas such as Florida, Hawaii and southern Texas it also nests outdoors. It is a known problem in hospitals and other institutions.^[9][20][2]

• ID: about 1/16 inch (Missouri: 1 to 2 mm), light yellow to reddish brown, two nodes, no spines on the thorax, and a three-segmented club at the tip of each antenna.^{[1][9][2][20]}
• Food: grease and fats, protein and sweets, plus dead insects, toothpaste and soap. They also look for water in kitchens and bathrooms.^[9][1]
• Nests: tiny voids behind baseboards, countertops and outlets and in wall voids, often warm and near moisture. Nests are very hard to find.^[9][2]
• Colony: many nests and up to hundreds of queens. There are no mating swarms; colonies spread by budding, when workers carry brood to a new spot, often with queens. Queens lay up to 35 eggs a day, and a worker develops from egg to adult in 36 days.^[9][20][2]
• Stings: a stinger is present, but Texas A&M says they don't sting people. Minnesota notes they have been known to carry diseases such as Salmonella.^[20][9]
• Bait, never spray: sprays and repellent dusts make colonies bud into more colonies. Baiting is the only effective method, placed widely along trails; Texas A&M says a program may take several months to a year, and Minnesota recommends a professional.^[2][20][9]

Thief ant (Solenopsis molesta)

A native ant found throughout the United States, also called the grease ant. It gets its name from nesting next to larger ants and eating their larvae and pupae.^[18][9]

• ID: golden yellow to light brown and tiny: UC IPM and Texas A&M give 1/32 inch, Minnesota about 1/20 inch. Two nodes. The antennae have a two-segmented club, which separates it from the pharaoh ant's three; dead thief ants tend to curl up.^[1][18][9]
• Food: protein and grease such as meat, cheese, peanut butter and nuts, also sweets. They are small enough to get into most food containers.^[9][18]
• Nests: outdoors in soil and rotting wood; indoors in wall and cabinet voids and behind baseboards. Colonies have several hundred to a few thousand ants and many queens.^[9][18]
• Stings: they carry a stinger, and the Mississippi Entomological Museum counts them as an occasional stinging pest.^[18][12]
• Bait: when the nest is indoors, Minnesota says baiting works best; use protein or grease baits. Ants foraging in from outside in mid to late summer often leave on their own.^[9][1]

Little black ant (Monomorium minimum)

A native, slow-moving, shiny black ant common in northern and eastern states and in California. Texas A&M's fire ant program notes it preys on red imported fire ant queens.^[3][24]

• Little black ants are shiny black and about 1/16 inch long, nesting in lawns, under stones and wood, and indoors in woodwork, wall voids, masonry and under carpets. Find every nest inside and out; baits usually control them.^[3]
• ID: about 1/16 inch, all one size, two nodes, antennae with a three-segmented club.^[3]
• Food: other insects and honeydew; indoors it raids pantries along well-marked trails.^[3][24]
• Colony: up to 2,000 workers with many queens.^[3]

Acrobat ants (Crematogaster)

Named for raising the heart-shaped abdomen over the body when disturbed. They are found across the United States.^[9][16]

• Acrobat ants: light brown to black, 2 1/2 to 3 mm long, with a heart-shaped abdomen that comes to a point; they nest in moisture-damaged door and window frames, dead wood and foam insulation, and eat sweet and greasy foods.^[2]
• ID: two nodes that attach to the top of the abdomen, and a pair of large spines on the thorax. Workers are about 1/8 inch and all one size.^[9][16]
• Nests: dead or rotting wood, old carpenter ant and termite galleries, wall voids, foam insulation, and window frames. Minnesota says they don't cause structural damage themselves.^[9][16]
• Stings: Missouri Extension lists acrobat ants among the state's stinging ants.^[2]
• Control: find and remove the rotted wood or nest; for nests in wall voids, a professional can apply insecticide dust. Correct the moisture problem.^[9][16]

Crazy ants: tawny (Rasberry) and longhorn

Both run fast and erratically and both are introduced. The longhorn crazy ant has much longer legs and antennae and a longer thorax than the tawny crazy ant.^[4][19]

• Tawny crazy ants, an invasive found around Houston since 2002, run rapidly and erratically, can build up in huge numbers, short out electrical equipment, and spread mostly by hitching rides in garbage, compost, potted plants and hay. They don't sting.^[4]
• Tawny crazy ant ID: reddish brown, uniformly about 1/8 inch, one node, hairy, with a ring of hairs at the tip of the abdomen instead of a stinger. It builds no mounds or central nests; colonies with many queens sit under rocks, timbers and debris.^[4]
• Tawny crazy ant impact: millions of ants in a yard, short-circuited electrical equipment, and harm to native wildlife. The Mississippi Entomological Museum records huge supercolonies on the southern coastal plain from Louisiana to Georgia and Florida. Bites cause a small pain that fades quickly.^[4][12]
• Tawny crazy ant baits: workers ignore most bait products. Texas A&M found the most attractive was an abamectin carpenter ant bait, which still doesn't give enough control alone and should be paired with contact treatments.^[4]
• Longhorn crazy ant ID: grayish black, 1/8 inch, very long legs and antennae, long coarse hairs. Colonies hold up to 2,000 workers and 40 queens, in potted plants, mulch, rotten wood and, indoors, wall voids near hot-water pipes and heaters. Feeds on insects, grease and sweets.^[19][24]
• Longhorn crazy ant range and bait: well established from South Carolina to Florida and Texas and found in California; farther north it survives only indoors. Texas A&M reports granular baits with abamectin or hydramethylnon attract and kill them, alongside liquid sugar baits in busy areas.^[19][12]

Red imported fire ant (Solenopsis invicta)

An invasive ant that infests most of 11 southern states and Puerto Rico and reached Southern California in 1998. It isn't established in Missouri or the upper Midwest. The Mississippi Entomological Museum ranks it a serious nuisance and stinging pest.^{[26][2][9][12]}

• ID: dark reddish brown with a darker abdomen, two nodes, and workers of mixed sizes from 1/16 to 1/5 inch (Texas A&M: up to almost 1/4 inch).^[26][1][25]
• Mounds: soft soil, often dome-shaped and up to about 1 foot high; Texas A&M says rarely more than 18 inches across. Mowed or dry-ground mounds can be flat and hard to see.^[26][25]
• Colony: single-queen colonies are territorial with fewer, larger mounds; multiple-queen colonies can hold hundreds of queens and more than 300 mounds per acre, and are harder to control.^[25][26]
• Stings: disturbed ants swarm up and sting all at once, and one ant can sting repeatedly, causing a burning feeling. A small percentage of people are allergic; chest pain, nausea, dizziness or shock after stings means get emergency care.^[26][25]
• Food: almost anything, including insects, seeds, seedlings and greasy food; fire ants prefer baits with oils.^[26][1]
• Bait: broadcast a product labeled as fire ant bait when ants are foraging (70° to 90°F is best); a greasy chip left out for 30 minutes shows whether they are active. Texas A&M's Two-Step Method pairs a once- or twice-a-year broadcast bait with treating individual problem mounds, and late August through October is a good time to bait.^[26][25]

Field ants (Formica)

Ants that build soil mounds in lawns. They are easily confused with carpenter ants because of their size and color, and with fire ants because of the mounds.^[9][2]

• ID: one node, an uneven thorax in profile, and three tiny simple eyes on top of the head. Black, brown, red or a mix; workers about 1/8 to 1/4 inch.^[9]
• Mounds: Minnesota says some species make mounds up to 10 inches across, and Missouri says up to a foot; the Allegheny mound ant can build mounds 6 feet wide. The Mississippi Entomological Museum lists mound or thatch ants as nuisance pests with large colonies.^[9][2][12]
• Food: honeydew, insects and household sweets. They don't nest inside buildings, and ants that wander in usually leave on their own.^[9]
• Control: tolerate when you can; otherwise treat the nest itself with dust, granules or a liquid drench.^[9][2]

Citronella ants (larger and smaller yellow ants)

Yellow ants named for the lemon or citronella smell they give off when crushed or threatened. Their winged swarmers often turn up in homes and get mistaken for termites.^[10][9][2]

• ID: yellow to reddish brown, one node. Larger yellow ant workers are 4 to 4.5 mm (Minnesota: about 3/16 inch); smaller yellow ant workers are 3 to 4 mm. Swarmers are about twice worker size, with smoky wings.^[10][9][2]
• Food: honeydew from aphids and mealybugs on roots underground; they are not known to forage for other food.^[10][2]
• Nests: in soil along foundations, under stones, logs and concrete slabs. Swarms can come up through slab cracks at any time of year, including winter from under heated slabs.^[9][10]
• Control: they won't breed indoors or damage food or the house. Vacuum the swarmers; Minnesota says treating nests under a slab is impractical and rarely needed.^[10][9]

Big-headed ants (Pheidole)

Ants with two worker sizes, the larger ones with a head far too big for the body. They are often mistaken for fire ants, but imported fire ants never have big-headed workers.^[21][24]

• ID: reddish brown, 1/16 to 1/8 inch, two nodes, two spines on the thorax, and a three-segmented antennal club.^[21]
• Food: insects, seeds and honeydew outdoors; meats, grease, fruit juice and peanut butter indoors, with a likely preference for protein.^[21][24]
• Range: the native Pheidole dentata is the most common species in the South, from Kansas to Virginia and Florida. The Mississippi Entomological Museum lists introduced big-headed ants in Florida and along the Gulf Coast as occasional household pests that compete with native ants.^[21][12]
• Bait: treat nests you can reach and use baits where you can't; Texas A&M calls indoor baiting effective and the safest method.^[21]

Ghost ant (Tapinoma melanocephalum)

A tropical tramp ant established in southern and central Florida and found indoors as far north as Iowa and Oregon. The Mississippi Entomological Museum lists it from Florida, Georgia, Louisiana, Mississippi and North Carolina, mostly in coastal areas outside Florida.^[17][12]

• Ghost ants are tiny, about 1/16 inch (1.3 to 1.5 mm), with a dark head and thorax and a pale, almost see-through abdomen and legs. A key house pest in Florida, they nest indoors in tiny spaces such as wall voids and even between books, favor sweets, and smell like rotten coconut when crushed.^[5]
• Colony: many queens and thousands of workers in linked nests that move often and bud into new ones, so spraying the workers you see is only a temporary fix.^[17]
• Bait: Texas A&M calls baits the best tactic and says boric acid (1-5%) in sugar or honey water seems to work well.^[17]

Harvester ants (Pogonomyrmex)

Large seed-gathering ants, mostly in the West and Southwest; the Florida harvester ant nests in deep sand in the Southeast. Along with native fire ants, they are the most common stinging ants in California.^{[27][23][12][1]}

• Red harvester ants are 1/4 to 1/2 inch, red to dark brown, with square heads. They clear bare circles 3 to 6 feet across around their nests and collect seeds. They're reluctant to sting, but the sting is painful and can be medically serious.^[7]
• Cleared areas vary: Texas A&M's urban entomology page gives an average of about 12 feet across, from 3 to 35 feet, and Utah State also gives about 12 feet. Foraging trails can run 200 feet out from the entrance.^[23][27]
• ID: red to brown or black, 1/5 to 1/2 inch, two nodes, with a row of hairs under the head that helps them carry large loads.^[27][23]
• Stings: painful, and some species leave the stinger in the wound. They don't invade homes but can make lawns and playgrounds unusable.^[27][23]
• Bait: granular ant baits labeled for lawns, spread around the nest opening, are very effective.^[27][23]

Asian needle ant (Brachyponera chinensis)

An East Asian ant now invasive in the Southeast, recorded in Alabama, Florida, Georgia, Mississippi, North and South Carolina and Tennessee. It has also spread to New Zealand.^[28][12][31]

• ID: about 1/5 inch, shiny black with orange-brown legs, a single long paddle-shaped node, and a visible stinger. Workers don't trail; they carry each other to food.^[28]
• Food and nests: mainly termites, plus other protein. Nests sit under leaf litter, pine straw and rotting logs in shady woods and can spread into yards.^[28]
• Stings: not aggressive, but it stings when pressed, often when someone lifts a log bare-handed. The sting is painful and can, rarely, cause life-threatening anaphylaxis in sensitive people.^[28][31]
• Control: rake heavy mulch and pine straw back from the house, move woodpiles away, seal gaps and wear gloves in the garden. There is some evidence protein-based granular baits work.^[28]

European fire ant (Myrmica rubra)

A Eurasian ant first found in Massachusetts in the early 1900s, now in at least seven states in the Northeast and also found in Washington State. It is not related to the southern imported fire ants.^[30][29]

• ID: reddish brown, about 1/5 inch, finely hairy, with ridged head and thorax, two backward-pointing spines and a two-segmented waist.^[29]
• Nests: no obvious mounds. Colonies with many queens nest in damp soil at the bases of trees and shrubs and under rocks and logs; they are most common in wetlands and moist woods. They spread in potted plants, soil and mulch.^[29][30]
• Stings: workers are aggressive and the sting is painful; it can cause severe allergic reactions, including anaphylaxis, in sensitive people.^[29]
• Bait: results with food-based baits have been inconsistent. Hydramethylnon baits have shown some effect, baits work best in early to mid summer, and repeated treatments may make colonies move.^[29]

Other ants you may meet

These are more regional pests.^[12][22]

• White-footed ants are small (about 1/8 inch), black with yellowish-white feet, and neither bite nor sting nor damage structures; in Florida colonies run from 8,000 to 3 million, foraging in kitchens, bathrooms and along trees with honeydew-making insects. They mainly spread on infested landscape plants.^[6]
• Texas A&M considers the white-footed ant the most difficult structure-infesting ant to control: colonies reach hundreds of thousands of workers, and the key mark is pale yellow feet on a black ant just over 1/8 inch long.^[22][6]
• Texas leafcutting ants (town ants) are rust brown with three pairs of spines on the thorax. Colonies under many 5- to 14-inch mounds strip leaves from plants, sometimes over an acre, to grow fungus underground; workers bite.^[8]

Finding the nest

When you see a trail, follow the ants to where they're entering the building and, if possible, to the nest. Check under sinks, in cupboards, and along pipes and electrical wires, which ants use as highways.^[1]

Most ants nest in soil, often next to buildings, along sidewalks, under boards, stones or stumps, or near plants with honeydew-producing insects such as aphids and scales. Check potted plants indoors.^[1]

• If ants are nesting in a potted plant, take it outside and submerge the pot for 20 minutes or more in 1 to 2 tablespoons of insecticidal soap per quart of water, just covering the soil.^[1]
• Ants climbing trees and shrubs are usually after honeydew; band trunks with a sticky barrier over a protective wrap and trim branches that touch buildings.^[1]

Prevention before the season starts

Learn your local ant season and be ready for annual invasions by caulking and baiting before the influx; baiting in late winter and early spring, when colonies are starting to grow, is most effective.^[1]

• Caulk cracks and openings, especially where pipes and wires enter.^[1]
• Store food in clean, sealed containers rather than bags or open packages, and clean up crumbs, grease and spills.^[1]
• Fix leaky faucets and sprinklers, and empty and clean garbage bins often.^[1]
• Keep plants, grass and mulch at least a foot from the foundation.^[1]

Using baits

Match the bait to the ant. Baits use sugars, proteins, oils or a mix as the attractant. Argentine ants take sweet baits all year; thief and pharaoh ants prefer protein or grease baits year-round; fire ants prefer oils. Set out a little of each and watch which they take.^[1]

Don't spray while baiting; it keeps ants from carrying the bait home. Baits act slowly and can take weeks to months to finish a colony, and food left out competes with them.^[9][1]

• Place bait stations every 10 to 20 feet around the foundation, near nest openings and along trails, out of reach of children and pets. Use baits indoors only for a serious infestation when you can't find the entry point.^[1]
• Common bait active ingredients include borates, fipronil, abamectin and hydramethylnon. For severe Argentine ant problems, liquid borate baits at 0.5% to 1% in refillable stations work best.^[1]
• Granules with cyfluthrin or permethrin look like baits but are contact insecticides that kill foragers without controlling the colony.^[1]
• Expect 5 to 10 days to see fewer ants; if they ignore a bait, move it or try a different product.^[1]
• If you hire a company, ask for baits and spot treatments rather than perimeter or monthly sprays. Avoid spraying pyrethroids such as bifenthrin outdoors on driveways, sidewalks and foundations; they pollute waterways.^[1]

Common questions

What are the small black ants in my kitchen?

Most often odorous house ants (brown to black, rotten-coconut smell when crushed), little black ants (shiny black, about 1/16 inch) or pavement ants (two nodes, grooved head). Follow the trail outside to find the nest and bait it.^[9][3][2]

What is a sugar ant?

It's a nickname, not a species. Texas A&M uses it for the pharaoh ant, a tiny yellowish ant that should be baited, not sprayed.^[20][2]

Which ants sting?

Fire ants (imported and native), harvester ants, Asian needle ants and European fire ants all sting, and fire ant, Asian needle ant and European fire ant stings can cause severe allergic reactions in some people. Carpenter ants bite instead, and tawny crazy ants have no stinger.^{[26][1][28][29][15][4]}

Do carpenter ants eat wood?

No. They chew out galleries to nest in and push out sawdust-like debris, but they feed on honeydew, insects and sweets.^[9][15]

Why did spraying make my ant problem worse?

With pharaoh ants, sprays and repellent dusts cause a colony to split into several new ones. Sprays also only kill the few workers that are out, not the queens.^[20][2][9]

Sources

1. University of California Statewide IPM Program, “Ants (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/ants/ (accessed 2026-11-10)
2. University of Missouri Extension, “Ants, G7392.” extension.missouri.edu/publications/g7392 (accessed 2026-11-10)
3. Texas A&M AgriLife Extension, Urban and Structural Entomology, “Little Black Ant.” urbanentomology.tamu.edu/urban-pests/ants/little_black/ (accessed 2026-11-10)
4. Texas A&M Center for Urban and Structural Entomology, “Tawny Crazy Ant (formerly Rasberry crazy ant).” urbanentomology.tamu.edu/urban-pests/ants/rasberry/ (accessed 2026-11-10)
5. University of Florida IFAS Extension, “Ghost Ant, Tapinoma melanocephalum (EENY-310/IN532).” edis.ifas.ufl.edu/publication/IN532 (accessed 2026-10-06)
6. University of Florida IFAS Extension, “White-Footed Ant, Technomyrmex difficilis (EENY-273/IN551).” edis.ifas.ufl.edu/publication/IN551 (accessed 2026-10-06)
7. Texas A&M AgriLife Extension, “Red Harvester Ant (Field Guide to Common Texas Insects).” web.archive.org/web/20250116042807/texasinsects.tamu.edu/red-harvester-ant/ (accessed 2026-10-06). Archived copy (Internet Archive, captured 2025-01-16); the original page https://texasinsects.tamu.edu/red-harvester-ant/ was retired and now redirects to the AgriLife Extension Entomology home page.
8. Texas A&M AgriLife Extension, “Texas Leafcutting Ant (Field Guide to Common Texas Insects).” web.archive.org/web/20241205060751/texasinsects.tamu.edu/texas-leafcutting-ant/ (accessed 2026-10-06). Archived copy (Internet Archive, captured 2024-12-05); the original page https://texasinsects.tamu.edu/texas-leafcutting-ant/ was retired and now redirects to the AgriLife Extension Entomology home page.
9. University of Minnesota Extension, “Ants.” extension.umn.edu/insects-infest-homes/ants (accessed 2026-11-10)
10. Penn State Extension, “Citronella Ants.” extension.psu.edu/citronella-ants (accessed 2026-11-10)
11. Penn State Extension, “Carpenter Ants.” extension.psu.edu/carpenter-ants (accessed 2026-11-10)
12. Mississippi Entomological Museum, Mississippi State University, “Common Pest Ants of the Southeastern United States.” mem.org.msstate.edu/Researchtaxapages/Formicidaepages/faunal.lists/Common_Pest_Ants.html (accessed 2026-11-10)
13. Texas A&M Urban and Structural Entomology Program, “Odorous House Ant, Tapinoma sessile.” urbanentomology.tamu.edu/urban-pests/ants/odorous-house-ant/ (accessed 2026-11-10)
14. Texas A&M Urban and Structural Entomology Program, “Argentine Ant, Linepithema humile.” urbanentomology.tamu.edu/urban-pests/ants/argentine/ (accessed 2026-11-10)
15. Texas A&M Urban and Structural Entomology Program, “Carpenter Ants, Camponotus sp..” urbanentomology.tamu.edu/urban-pests/ants/carpenter/ (accessed 2026-11-10)
16. Texas A&M Urban and Structural Entomology Program, “Acrobat Ant, Crematogaster sp..” urbanentomology.tamu.edu/urban-pests/ants/acrobat/ (accessed 2026-11-10)
17. Texas A&M Urban and Structural Entomology Program, “Ghost Ant, Tapinoma melanocephalum.” urbanentomology.tamu.edu/urban-pests/ants/ghost/ (accessed 2026-11-10)
18. Texas A&M Urban and Structural Entomology Program, “Thief Ant, Solenopsis molesta.” urbanentomology.tamu.edu/urban-pests/ants/thief/ (accessed 2026-11-10)
19. Texas A&M Urban and Structural Entomology Program, “Longhorn Crazy Ant, Paratrechina longicornis.” urbanentomology.tamu.edu/urban-pests/ants/crazy/ (accessed 2026-11-10)
20. Texas A&M Urban and Structural Entomology Program, “Pharaoh Ant, Monomorium pharaonis.” urbanentomology.tamu.edu/urban-pests/ants/pharoah/ (accessed 2026-11-10)
21. Texas A&M Urban and Structural Entomology Program, “Big-Headed Ant, Pheidole sp..” urbanentomology.tamu.edu/urban-pests/ants/big_headed/ (accessed 2026-11-10)
22. Texas A&M Urban and Structural Entomology Program, “White-Footed Ant, Technomyrmex difficilis.” urbanentomology.tamu.edu/urban-pests/ants/white_footed/ (accessed 2026-11-10)
23. Texas A&M Urban and Structural Entomology Program, “Red Harvester Ants, Pogonomyrmex barbatus.” urbanentomology.tamu.edu/urban-pests/ants/red_harvester/ (accessed 2026-11-10)
24. Texas A&M AgriLife, Texas Imported Fire Ant Research and Management Project, “Native Ants.” fireant.tamu.edu/learn/native-ants/ (accessed 2026-11-10)
25. Texas A&M AgriLife, Texas Imported Fire Ant Research and Management Project, “Fire Ant FAQ.” fireant.tamu.edu/manage/faq/ (accessed 2026-11-10)
26. University of California Statewide IPM Program, “Pest Notes: Red Imported Fire Ant (Home and Landscape).” ipm.ucanr.edu/home-and-landscape/red-imported-fire-ant/ (accessed 2026-11-10)
27. Utah State University Extension, “Harvester Ants, Pogonomyrmex spp..” extension.usu.edu/pests/ipm/ornamental-pest-guide/insects/hymenoptera/harvester-ants (accessed 2026-11-10)
28. Mississippi State University Extension, “Pest Snapshot: Asian Needle Ant (Brachyponera chinensis), Publication 4142.” extension.msstate.edu/sites/default/files/document/2025-10/P4142_web.pdf (accessed 2026-11-10)
29. Washington State University Pestsense, “European fire ant.” pestsense.cahnrs.wsu.edu/fact-sheet/european-fire-ant/ (accessed 2026-11-10)
30. Environmental Entomology, abstract via PubMed, “Chen and Adams 2018, The distribution and habitat affinities of the invasive ant Myrmica rubra in southern New England.” pubmed.ncbi.nlm.nih.gov/29659763/ (accessed 2026-11-10)
31. Clinical and Experimental Allergy, abstract via PubMed, “Lee et al. 2009, Characterization of the major allergens of Pachycondyla chinensis in ant sting anaphylaxis patients.” pubmed.ncbi.nlm.nih.gov/19178543/ (accessed 2026-11-10)