Imported Red Fire Ants - Their Threat To Humans
Continues
If you have been in Texas,
or almost anywhere in the south for more than twenty four hours, you
have no doubt encountered or at least seen evidence of the Red Imported
Fire Ant.
Fire ants were accidentally introduced into Mobile,
Alabama from South America more than sixty years ago. They now infest
more than 260 million acres. They reached Texas in the early 50's and
spread throughout the eastern two thirds of the state and moving on. Thousands
of reproductive females are produced per colony, and when mated begin
a new colony wherever they land. This presents a major control problem
as well as a quarantine problem
Fire ants are aggressive and will attack anything that goes near them.
They sting repeatedly, seemingly onsignal and all at the same time. Once
stung a white pustule forms on the skin as seen in the picture below.
The stings are not normally life threatening but the pustules once broken
are easily infected and leave permanent scars. Some people are sensitive
or allergic to the sting. In those cases, symptoms may include chest pains,
nausea, severe sweating, loss of breath, serious swelling, slurred speech,
and in severe cases lapse into a coma. In those cases, the person should
be taken to an emergency facility.
Fire Ant Biology
Fire ants are omnivorous, feeding on almost
any plant or animal material, insects however seem to be their preferred
food. The arrival of fire ants in an ecosystem can wreck havoc on the
local ecological community. Studies have been shown that a minimum of
twofold reduction occurs among populations of field mice, snakes, turtles,
and other vertebrates when fire ants are allowed toestablish colonies
in a given area. In some instances entire species have been eliminated
from a habitat due to fire ants. In agricultural areas, Fire ants have
been documented at damaging fifty seven species of cultivated plants.
Fire ant colonies consist of eggs, brood, workers, winged males, winged
females, and one or more reproductive queens. At maturity, a single queen
fire ant colony can consist of 250,000 ants. The queen lives for up to
seven years and produces an average of 1600 eggs per day throughout her
life.
Alate, or winged forms, are most abundant in the late spring and early
summer, but can be found throughout the year. Nuptial flights usually
occur in mid morning one or two days after a rainfall when the temperatures
are above 22 degrees centigrade. The males fly first and await the female
in the air. The females meet them and mate in the air. The males die after
mating. The females shed their wings and search for a suitable nesting
site.
Alate, or winged forms, are most abundant in the late spring and early
summer, but can be found throughout the year. Nuptial flights usually
occur in mid morning one or two days after a rainfall when the temperatures
are above 22 degrees centigrade. The males fly first and await the female
in the air. The females meet them and mate in the air. The males die after
mating. The females shed their wings and search for a suitable nesting
site.
One of the identifying characteristics of a fire
ant colony is their mound as seen as here. There are usually no external
openings in the mound. Tunnels below the surface radiate from the mound
allowing foraging workers easy entrance and exits. The purpose of the
mound is for three reasons: a flight pad for nuptial flights, to raise
the colony above the water table in saturated ground, and to supply warmth
like a solar panel during cold months.
Mounds are an important part of the colony,
but not essential. In hot weather they are sometimes abandoned. With sufficient
moisture and food, fire ants will nest in a wide variety of sites such
as rotten logs, under pavement, in dried cow manure, in electrical boxes
near the ground, inside homes, and from a few reports in automobiles which
would definitely cause road rage.
The ant nests are mounds about the size of mole
hills littered throughout the landscape. Should you be so foolish or unlucky
to disturb a mound, you will be greeted by thousands of ants. They are
small, 1/8 to 3/8 inches in size, rusty brown with a black abdomen, and
they sting. The sting feels like a match was put out on your skin. Symptoms
of the sting include burning, itching, and a white pustule that forms
in a few days.
The stings are not usually life threatening
however the pustule often opens and can become infected and leave scars.
The ants can also sting repeatedly, and with enough ants on you stinging
can cause some severe problems. Some are also sensitive to the sting,
or allergic. In these cases one or more stings may lead to chest pains,
nausea, severe sweating, loss of breath, serious swelling, and slurred
speech. Some may even lapse into a coma after only one sting. Immediate
medical emergency attention must be given to anyone displaying those symptoms.
There have been some fatalities documented, but few compared to bee and
wasps stings.
This picture was taken after a rain. The pan contains
used charcoal from a smoker. Apparently there was a nest hidden in the
spent coal. When it flooded the ants form an ant arc sacrificing some
for the good of the colony. This happens frequently in nature, and accounts
for the ants surviving floods and some of their rapid movement from place
to place. You have to admire their persistence, at least until your bitten.
