Fire Ants Ssolenopsis invicta
There are many sizes of workers in the colony, ranging from 1/8-inch to
almost 3/8-inch in length.
Fire ants pose a health risk to anyone venturing into areas where the ants
are found. Although the vast majority of stings result only in a raised welt that may develop a white pustule, a
person allergic to insect stings could experience a more serious reaction. Additionally, a person seldom receives
just one sting. Rather, dozens or even hundreds of stings can be inflicted quickly on a person accidentally
kneeling or standing next to or on a fire ant mound.
The red imported fire ant was brought into this country during the 1920s
and has spread to cover most of the Gulf Coast states and most of eastern Texas. It is now established north into
parts of Tennessee and North Carolina. These ants nest in the soil and construct large mounds that are easily seen
in lawns and pastures. A single lawn may contain a dozen or more mounds. This ant will also locate nests within
landscape mulch and beneath items on the ground, such as landscape timbers. The mounds of such colonies may be
shallow and poorly structured, making them difficult to detect for the less experienced eye. Fire ants may
construct mounds next to the foundation and enter homes through weep holes or other exterior cracks and holes. Once
inside, workers forage in trails beneath the edge of carpeting. On occasion, the ants will bring soil up into walls
or beneath first floor bathrooms and construct a nest.
Because of the health threat posed by fire ants, it is important to take
steps to control the ants around the home and in the yard. Over-the-counter fire ant baits can be effective if
properly used, but regular applications are necessary because the ants readily reinvade from neighboring
properties. Many homeowners employ the services of a professional company.
Fire ants typically nest outdoors in
dome-shaped mounds, some up to 4 inches high, or can be found next to or underneath timber, logs, rocks, pavers,
bricks, etc. Mounds will not always be evident, but are usually found in open areas such as lawns, pastures, and
along roadsides. Mounds of 1 to 2 feet in diameter and about 1/2-foot high have been seen. Very active and
aggressive, they will sting any intruding animal repeatedly.
Single-queen mounds can have up to 250,000 workers and will fight other fire ant colonies, and can result in 40-150
mounds per acre. Multiple-queen can have upwards of 500,000; since they do not fight other fire ant colonies, their
mounds are found closer together, and can reach densities of 200 to 800 mounds per acre!
In addition to stinging humans, fire ants can sting pets, livestock, and wildlife. Crop losses are also reported
due to fire ants feeding on seedlings and even citrus trees. They will also nest in A/C units and gas and water
meter boxes; electrical equipment and utility housings may serve as fire ant nest sites, sometimes resulting in
Due to the overly-aggressive nature of the fire ant and the potential health hazards associated with its sting, we
advise immediate pest control measures be taken if any fire ant infestation is discovered (especially if you have a
confirmed allergy associated with these particular ants).
Repeat applications of pest control chemicals by an experienced exterminator is often the safest and most effective
way to treat fire ant infestations. Many theories on how to eradicate them exist, but few, if any, really work.
Some think they can be drowned, but fire ant colonies have been known to latch onto floating debris, alive and
angry, during serious floods. Also, be sure to watch for visible mounds when mowing your lawn; passing over one
will send thousands of stinging ants in all directions. The job of eliminating fire ants is best left to a
Omnivorous. Known to eat meats, greasy and sweet materials.
Total time from egg to adult averages 30 days; workers live up to 180 days; queens live two to six years.
Fire Ant Facts
Though not a native species in North America, the red imported fire ant has become a common nuisance throughout
the southern United States such as Florida and Georgia. The Solenopsis invicta, or red imported fire ant, was
brought into the United States in the 1930′s via a shipment of cargo. Initially transplanted into Alabama, they
have spread and thrived throughout the southern states with the warm climate and lack of predators. They have been
found as far west as California and as far north as Maryland.
Fire ants favor warm, sunny conditions. They prefer dry fields and avoid shady areas such as woods. Their mounds
can grow up to 24 inches in diameter and 18 inches high. These colonies can contain several hundred thousand ants,
including at least one queen.
When attacking, fire ants first use their mandibles to attach themselves to their prey, and then inject venom
through the stinger. Fire ant stings are painful for most humans and fatal to some: if a victim experiences a
severe reaction such as sweating, nausea or excessive itching, emergency medical services should be contacted
immediately. Most sting victims experience painful red bumps: a topical antihistamine and a cold compress may help
in soothing fire ant stings. Their sting, which includes alkaloid venom, is highly irritating to humans and results
in red bumps and white pustules, which can ultimately lead to scarring. The sensation of a fire ant burn has been
described as “stinging” and “intense burning,” and fire ants are known to attack potential threats or prey in large
numbers. A fire ant colony may contain 100,000 to 500,000 insects, thus increasing the likelihood that multiple
stings will be inflicted.
Annual Fire Ant Treatment and Prevention
Because fire ants are not a native species in North America, developing strategies for their control has proven
difficult. The most reliable method of fire ant treatment and prevention is to have your local pest control company
perform an inspection and determine how to kill the fire ants in your area.
To prevent bites or stings away from the home, be cautious around large open areas. If you see a fire ant mound,
keep an eye on the ground to watch for ant activity. If you can, stick to the shade and cooler areas, as fire ants
prefer sunny locations.