Allegheny Mound Ant

Facts, Identification & Control

Latin Name: Formica exsectoides


Allegheny mound ants have a reddish thorax and head. The abdomen and legs are dark brown to black. The workers vary in size from 3.2 to 6.3 mm. They will not sting, but they can be aggressive and bite if the mound is disturbed.

Behavior, Habits & Diet 

The workers make tunnels and galleries in the ground. The tunnels extend as deep as almost 1 m (~3 ft) into the soil. As they dig, the workers pile the excavated soil up to make the mound. The mounds can reach records of about 5 m (~16ft)  in diameter, especially with older nests found in fields and wooded areas. The mounds that these ants build are frequently mistaken for fire ant mounds.

Allegheny mound ants nest in fields, pastures and wooded areas. They also live in in rural suburban playgrounds areas and residential lawns. They do not usually enter homes, but workers often forage on decks and patios.

Allegheny mound ants eat insects and honeydew, a sweet substance produced by sap-feeding insects like scales or aphids. The workers protect aphids and other insects that produce honeydew. The ant workers sometimes damage trees and shrubs by chewing openings in the bark and spraying formic acid. This is done to kill trees that are shading the nests. If these ants are disturbed, they give off a distinct formic acid odor.

If Allegheny mound ants are nesting on a property, it is usually best to call a pest control professional. There are several methods they can use to control Allegheny mound ants.


Queens produce eggs that become workers and reproductives. To establish a new colony, a mated queen and a contingent of workers leave the colony to select a new nesting site.

Signs of Allegheny Mound Ant Infestation

The most visible sign of Allegheny mound ants is the mound, that how they came up with their name. Few other ants in the U.S. build as visible a mound. Other signs would be the workers as they forage for food.

More Information

The Allegheny mound ant is a type of mound-building ant in the United States. These ants are found along the Atlantic coast from Nova Scotia to Georgia. They are most common in the Midwest and Northeast.


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