How Can I Tell If I Have Fire Ants?
Colony Characteristics
 |
 |
 |
 |
You may have fire ants if....
- You see a mound of fluffy, worked soil, particularly a few days after a heavy rain.
- The mound has no opening in the center like most ant mounds. Imported fire ants leave and enter the mound through underground tunnels, radiating from the mound. In hard compact soils, these tunnels become visible on the surface. They also have tunnels extending down to the water table when no surface water is available.
 |
 |
 |
- Most mounds in turfgrass are just a few inches tall, but undisturbed mounds can reach 18 inches in height.
 |
 |
 |
 |
 |
- Soil type can also affect mound size. Mounds in clay soil are often larger than sandy soils.
- Mounds are often built up against structures or may be located at sites with less disturbance (e.g., fence rows).
- The white objects seen in the mound are the brood—the eggs, larvae and pupae of developing ants.
Fire Ant Characteristics and Aggressive Nature
- Fire ants are small, only about 1/8 to 1/4-inch long. Variation in size is a distinguishing feature (Fig. 2). Many other ant species are uniform in size.
|
|
|
- Where imported fire ants are common, most homeowners recognize them by the mounds they build or the stings they inflict. Their aggressive nature compared to other ant species is one such trait. If a mound is disturbed, usually hundreds of fire ant workers will swarm out and run up vertical surfaces to sting.
 |
 |
 |
 |
 |
 |
 |
- Worker ants bite with their chewing mouthparts and inject venom with their stingers aggressively and repeatedly. If you get stung, you may feel burning or tingling at the site. A day or so later, the imported fire ant's unique venom forms a characteristic white fluid-filled pustule or blister at the sting site. For more information, see Fire Ant Stings.
Watch what happens when a fire ant nest is disturbed: Disturbing a Fire Ant Mound.
Fire Ant Identification
Accurately identification of fire ants can be especially important in the southwestern states, where native fire ant species are common and imported fire ants are rare. Although native fire ants are common urban pests, if they are controlled unnecessarily, especially in very dry climates, imported fire ants are more likely to invade new areas. For information about suspected fire ant invasions in West Texas and beyond, see Living on the Edge: Management Considerations for Imported Fire Ants in Western Texas, Near or in Recently Infested Areas.
If you are unsure of the ant species you have, contact your county Extension office for identification help. Properly identifying ant species is the first step in determining the need and approach for control. Here are some identification characteristics of imported fire ants:
- Side view of a fire ant, nodes and stinger are visible
- Two petiole nodes between the thorax and gaster. Click on image to enlarge.
- 10 segmented, elbowed antennae with a long scape (see segment 1, click photo to enlarge) and a two-segmented club (see segments 9 and 10).
- Red imported fire ants have 4 "teeth" on each mandibles with 3 clypeal projections.
- Red imported fire ants have a reddish colored head and thorax. Black imported fire ants are darker. There may be gradations in color range.
Related Information:
These publications are also helpful:
- Ants (Formicidae) of the Southeastern U.S.
- Managing Household Ant Pests (B-6183)
- The Pest Ants of Louisiana: A Guide to Their Identification, Biology and Control
- Texas Pest Identification: An Illustrated Key
- Texas Fire Ant Identification: An Illustrated Key
- The Common Ant Genera of Texas (B-6138) (Note: This is a for sale publication.)
