Allegheny Mound Ants
- Latin Name: Formica exsectoides
- Size: About 3-6 mm on average
- Color: Reddish head and thorax with darker, almost black, hindquarters. Sometimes mistaken for fire ants.
- Found in: All down the East Coast, particularly in Georgia, North Carolina, and Virginia; across to the Western Appalachian Mountains. They’re also common in the Midwest and Northeast.
- Overview: These ants are identified by their large above-ground mounds. Though they don’t sting, they’ll bite if their mound is disturbed.
About Allegheny Mound Ants
This species of ant primarily lives in fields and pastures. They prefer wide open spaces where they can build their above-ground mounds unmolested. The mounds are constructed after thorough excavation (up to three feet deep!) by the worker ants, during which they dig out soil in diameters up to five feet wide.
Allegheny ants prefer not to interact with humans and animals so they’re rarely found indoors. They frequently build their nests on playgrounds and in other public areas inadvertently – people often mistake them for fire ant mounds. Workers from the ant colonies spread out far and wide to forage for food – a favorite is aphid honeydew – and can be seen on patios and decks from time to time.
If an Allegheny Mound Ant is spotted it’s best to leave it be. If possible, follow the ant to its nest to identify the mound and call in a pest professional immediately.
Facts About These Ants
Allegheny Mound Ants are one of the few species whose colonies are populated by multiple queens. They’re highly-protective of their nests and actually kill all foliage within 40-50 feet from their mounds so the shade won’t block the sunlight they use to heat the nests. Workers do so by spraying formic acid on nearby trees and shrubs which emits a powerful odor.
Their mounds are highly-complex and use the sun to naturally heat and cool the internal temperature. In some cases, several nests can be connected by underground tunnels forming what’s essentially ant “cities.” Allegheny Ants are persistent and the underground nature of their nests makes them difficult to eradicate without professional assistance and in many cases, multiple treatments.