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Red Imported Fire Ant Information
Background
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
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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 |
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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
- Workers
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.
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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 |
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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
Medical Problems
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.
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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.
http://www.ars.usda.gov/fireant/
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