Red Imported Fire Ant Information
The red imported fire ant (RIFA) is a nuisance, and its sting can cause medical problems. Fire ants can interfere with outdoor activities and harm wildlife. And mounds are unsightly and may reduce land values.
The ants are an established pest in 11 southeastern states, including: Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina, and adjacent regions in North Carolina, Arkansas, Tennessee and Oklahoma.
The historical progression of the Red Imported Fire Ant
Where They Infest
|Fire ants commonly infest lawns, school yards, athletic fields, golf courses and parks. In these places, they pose a medical threat to people and animals. Their mounds also detract from the aesthetic value of the land-scape.
Homes and Building – Fire ants form colonies close to homes and other buildings sometimes forage indoors for food and moisture, particularly during the hot, dry summer months. Entire colonies occasionally nest in wall voids or rafters, sometimes moving into buildings during floods. They are a nuisance and can threaten sleeping or bed-ridden individuals and pets.
|Home Gardens – Ants occasionally feed on vegetable plants in home gardens. The worst damage usually occurs during hot, dry weather. Ants may also be a nuisance to gardeners during weeding and harvesting.
Electrical Equipment and Utility Housings – Like many other ants, fire ants frequently infest electrical equipment. They chew on insulation and can cause short circuits or interfere with switching mechanisms. Air conditioners, traffic signal boxes, and other
|devices can be damaged. Fire ants also nest in housings around electrical and utility units. The ants move soil into these structures, which causes shorting and other mechanical problems.
Compost Piles, Mulched Flower Beds, Pavement Cracks, etc. – Fire ants invade compost piles and mulched flower beds seeking warmth and moisture. They also nest under cracked pavement, removing dirt from underneath sidewalks and roadways and aggravating structural problems. Colonies in these sites may be difficult to locate.
Around Bodies of Water – Fire ants require water to survive and are often found near creeks, run-off ditches, streams, rivers, ponds, lakes and other bodies of water. If surface water is unavailable, they tunnel down to the ground water table many feet below the ground.
Fire Ant Biology
Red imported fire ant colonies consist of the brood (eggs, larvae and pupae) and several types of adults:
- Winged males (distinguished from the females by their smaller heads and black bodies);
- Red-brown winged females;
- One or more queens (wingless, mated females); and
For a biological description of the red imported fire ant, click Here
Worker ants are wingless, sterile females. They protect the queen by defending the nest from intruders, by feeding the queen only food the workers have eaten first, and by moving the queen from danger. They also forage and care for the brood.
|The winged ants – or reproductives – live in the mound until their mating flight, which usually occurs in the afternoon, soon after a rainy period. Mating flights are most common in the spring and fall. Males die soon after mating, while the fertilized queen alights to find a suitable nesting site, sheds her wings, and begins digging a chamber in which to start a new colony. Sometimes several queens can be found in a single nesting site.
A newly-mated queen lays about a dozen eggs. When they hatch 7 to 10 days later, the larvae are fed by the queen. Later on, a queen fed by worker ants
|an lay up to 800 eggs per day. Larvae develop in 6 to 10 days, and then pupate. Adults emerge from the pupae in 9 to 15 days.
The average colony contains 100,000 to 500,000 workers and up to several hundred winged ants and queens. Queen ants can live seven years or more, while worker ants generally live about five weeks, although they can survive much longer.
The ants build mounds in almost any type of soil, but prefer open, sunny areas such as pastures, parks, lawns, meadows and cultivated fields. Mounds can reach 18 inches in height, depending upon the type of soil. Often mounds are located in rotting logs, and around stumps and trees. Colonies can also be found in or under buildings.
Colonies frequently migrate from one site to another. The queen needs only about six workers to start a new colony. They can develop a new mound, several hundred feet away from their previous location, almost overnight.
To learn the differences between common ants and the red imported fire ant, click Here
Fire ants are aggressive and will defensively attack anything that disturbs them. They can sting repeatedly. After firmly grasping the skin with its jaws, the fire ant arches its back as it inserts its rear-end stinger into the flesh, injecting venom from the poison sac. It then typically inflicts an average of seven to eight stings in a circular pattern. Fire ant venom is unique because of the high concentration of toxins which are responsible for the burning characteristic of such stings.
||Symptoms of a sting include burning and itching, which usually subsides within 60 minutes. This is followed by the formation of a small blister at the site of each sting, within the next four hours. And, a white pustule forms in a day or two. Treatment is aimed at preventing secondary bacterial infection, which may occur if the pustule is scratched or broken.
Although the stings are not usually life threatening, they are easily infected and may leave permanent scars. On rare occasions, anaphylaxis – or a generalized, systemic allergic reaction to the fire ant stings can occur, and may be life-threatening. It usually occurs in persons sensitized by a previous sting. It may be manifested by flushing, general hives, swelling of the face, eyes, or throat, chest pains, nausea, severe sweating, loss of breath, serious swelling or slurred speech. If this occurs, the person should immediately seek emergency medical assistance
Treatment – Elevate the extremity and apply ice or a cold compress to reduce swelling and relieve pain. Clean blisters with soap and water to prevent secondary infection. Do not break the blister. Topical steroid ointments and oral antihistamines may relieve the itching associated with these reactions. Treatment with antihistamines and oral steroids may be useful in severe cases.
Avoiding Medical Problems – Tips for avoiding medical problems include:
- Fire ant allergic patients should wear closed-toed shoes, socks, and gloves when gardening, and take other precautions to avoid stings;
- Fire ant mounds near the home should be identified and treated with an ant bait insecticide; and
- Teach children about fire ants and their hazard. These preventive measures should help reduce the health hazards caused by fire ant stings. Your allergist can provide you with more information on fire ant stings.
This fact sheet was prepared by the
California Department of Food and Agriculture,
with supplemental information provided by the
Texas Agricultural Extension Service.