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Ants are social insects that live in colonies or nests usually located in the soil near the house foundation, under concrete slabs, in crawlspaces, in structural wood, in the yard or garden, in trees and in other protected places. Some ants are a nuisance, others can cause structural (economic) damage or health risks to humans.

Ants Commonly Found In and Around Structures

Infestation of pavement ants
Infestation of pavement ants (Tetramorium caespitum). They are found outdoors unders stones, in pavement cracks and in crevices of masonry and woodwork.

pavement ants
Pavement ants enter homes through cracks in foundations and masonry. They are attracted to sweet foods.

Larger yellow ants
Larger yellow ants (Acanthomyops interjectus) live in the soil next to building foundations, in cracks in foundations and masonry, or in rotting wood.

Carpenter Ants

Black—Componotus pennyslvanicus

Red—Componotus ferrugineus

close-up of carpenter ant
Black carpenter ant.

wood damage from carpenter ants
Carpenter ants are a nuisance by their presence when found in the home. They do not eat wood, but remove quantities of it to expand their nest size, sometimes causing structural damage.

sawdust from carpenter ant damage
Sawdust from carpenter ant damage.

Pharaoh AntMonomorium pharaonis

pharaoh ant adult top view

pharaoh ant adult side view

Pharaoh ants are light yellow to reddish brown and almost transparent. Workers are about 1/16-inch long. They eat a wide variety of foods, especially those containing fat, grease or sugar, but they will also eat many things other ants rarely consume, such as toothpaste and soap. They are considered one of the most difficult ants to control and pesticides can cause them to bud, creating new colonies.

Ants Found in Lawns

European Fire Ant—Myrmica rubra

European fire ant Infestation

close-up of European fire ant

Myrmica rubra is not native to the United States. It has become a significant pest because these aggressive, stinging ants interfere with people's use and enjoyment of their properties, gardens and parks. When disrupted, the ants will deliver a painful sting which has in a few cases produced severe allergic reactions to the venom including anaphylactic shock.

Allegheny Mound Ant—Formica excectoides

allegheny mound ant mound
This ant normally lives outdoors with nests consisting of huge conical mounds, sometimes measuring nearly 3 feet high by 6 feet in diameter.

allegheny mound ants
New colonies are founded by extension of or breaking off from existing colonies when workers migrate away with one or more queens.

allegheny mound ants up close
Allegheny mound ants feed on insects (dead and alive) and the sweet honeydew produced by aphids and similar insects.

Ants vs. Termites

diagram of termite and ant

People often confuse winged termites with ants, which often swarm at the same time of year. To differentiate, look at the midsection, antennae and wings.

Midsection: The ants have “wasp waists.” Between the thorax and the abdomen is a narrow connection in ants, just like with wasps. The termites do not have this slender waist.  Their width continues, gradually increasing, from the thorax to the abdomen.

Antennae: Termites have straight antennae; on ants the antennae have elbows.

Wings: All four of the wings of a termite are about the same length. The two rear wings of a flying ant are shorter than the front wings.

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Ants—Identification and Control Information

Carpenter Ants—Identification and Control Information

Pharaoh Ants—Identification and Control Information

Fire Ants—Identification and Control Information

Allegheny Mound Ant

[Photos, left to right: (pavement ants) Joseph Berger,; (pavement ants) Joseph Berger,; (larger yellow ants) Howard Ensign Evans, Colorado State University,; (black carpenter ant) Clemson University - USDA Cooperative Extension Slide Series,; (carpenter ant damage) R. Werner, USDA Forest Service,; (carpenter ant damage) Edward H. Holsten, USDA Forest Service,; (European fire ants); ((European fire ant); (Allegheny mound ants) Catherine Herms, The Ohio State University,; (Allegheny mound ants); (Allegheny mound ants) Steve Wilson; (ant vs. termite diagram) USDA Forest Service Archive, USDA Forest Service,; (Pharaoh ants) Pest and Diseases Image Library,]