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Fire Ants

Identification, Habits, and Control
Closeup photo of a Carpenter Ant on white background

About Fire Ants

Genus: Solenopsis spp.

Fire ants are aggressive, stinging pests that build large colonies in soil, often in open, sunny areas like lawns, fields, and along foundations. Their visible mounds and rapid swarming behavior make them a common and potentially dangerous problem around homes and businesses.

Fire ants are not just a nuisance—they can pose risks to people, pets, and property. Colonies spread quickly and can be difficult to control without professional treatment, especially as new mounds continue to develop across a property over time.

How to Identify Fire Ants

Size

  • Workers range from 1/8 to 1/4 inch long
  • Multiple sizes present within the same colony
  • Queens significantly larger, up to 1/2 inch

Color

  • Reddish-brown body with darker abdomen
  • Color may vary slightly from light red to deep brown
  • Often appear darker when clustered in large numbers

Identifying Characteristics

  • Aggressive ants that swarm quickly when disturbed
  • Painful stings that create white pustules
  • Build large, dome-shaped mounds without visible openings
  • Antenna with two-segmented club at the tip

Where You’ll Find Them

  • Open, sunny areas like lawns and fields
  • Along sidewalks, driveways, and foundations
  • Around electrical boxes and HVAC units
  • Near moisture sources after rain or irrigation

Behavior and Risks

Fire ants build mounds in almost any type of soil, but they prefer open, sunny areas such as pastures, parks, lawns, meadows and cultivated fields. Mounds can reach 1’ in height and 1-2’ in diameter depending on the type of soil. Fire ant mounds are easily visible in the yard and adjacent to foundation walls, especially a few days after a hard rain. Also, if you notice reddish-brown ants of different sizes in a group actively foraging, it could be an indication of the presence of fire ants. The fire ant will occasionally invade homes, nesting under bathtubs and around water heaters. They commonly gain entry to a home through foundation vents and HVAC systems (such as wall air-conditioning units). This is one of the most dangerous ant species from a human perspective, due to its ability to sting. People who are allergic to stings from bees and wasps may suffer serious reactions to the sting of the fire ant. Fire ants also negatively impact pets, livestock, as well as wild animals, and can cause damage to landscapes, electrical systems, highways, roadways, airport runways and farm implements.

The black imported fire ant was introduced from South America into the United States at Mobile, AL, in the early 1900s, and the red imported fire ant was introduced at the same port in the 1930s through the soil used as ballast or dunnage in ships carrying agricultural goods.