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Ants |
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Ant Biology |
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Fire Ant |
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Pharoah Ant |
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Carpenter Ant |
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Other Ants |
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Preventive
Measures |
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Treatment |
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Ant Biology |
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Fire Ant |
Red imported fire ants
infest the eastern two-thirds of Texas. They build hills or
mounds in open areas where the colonies live, although colonies
occasionally occur indoors and in such structures as utility
housings and tree trunks. When a mound is disturbed, worker ants
mount a rapid defense, quickly running up vertical surfaces.
Worker ants range from 1/16 to 3/16 inch (1.5 to 5 mm) long and
are dark brown. Queen ants are larger (3/8 inch) and lose their
wings after mating.
Sterile female fire ant workers can sting repeatedly. First they
bite; then, while holding onto the skin with their jaws, they
inject venom with stingers at the end of their abdomens. The
unique venom produces a fire-like burning sensation. Most people
react by developing a whitish pustule or fluid-filled blister at
the sting site after a day or two. Those hypersensitive to the
stings should be prepared for a medical
emergency if stung. Most people can tolerate multiple stings,
but may have problems with secondary infections at the sting
sites.
Fire ants are considered to be medically important pests of
people, pets, livestock and wildlife. Although omnivorous, fire
ants primarily eat insects and other invertebrates. Their
predatory activities suppress populations of ticks, chiggers,
caterpillars and other insects.
Life cycle: Complete metamorphosis. Eggs hatch in eight to 10
days; larvae develop through four stages (instars) before
pupating. Development requires 22 to 37 days, depending on
temperature. Fire ants are social insects, with each colony
containing one or more queen ants. Queen ants can produce about
800 eggs per day. A “mature” colony can contain more than
200,000 ants along with the developmental and adult stages of
winged black-colored male and reddish-brown female
reproductives. These ants stay in the colony until conditions
exist for their nuptial flight. |
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Pharoah Ant |
This is the most commonly occurring indoor ant in Texas. Also
called “sugar ants” or “piss ants,” these are some of the smallest
ants, about 1/12 to 1/16 inch long, with light tan to reddish
bodies. In hospitals, they have been suspected to be carriers of
more than a dozen pathogenic bacteria including Staphylococcus,
Salmonella, Pseudomonas and Clostridium. These ants do not sting
and usually do not bite.
Pharaoh ants are omnivorous, feeding on sweets (jelly,
particularly mint apple jelly, sugar, honey, etc.), cakes and
breads, and greasy or fatty foods (pies, butter, liver and
bacon). Nests are found rarely outdoors and almost anywhere
indoors (light sockets, potted plants, wall voids, attics, in
any cracks and crevices), particularly close to sources of
warmth and water.
Life cycle: Complete metamorphosis. A worker ant develops from
an egg (5 to 6 days) through several larval stages (22 to 24
days), a prepupal stage (2 to 3 days), a pupal stage (9 to 12
days) to an adult ant. Development from egg to adult takes from
38 to 45 days (4 days longer for sexual forms).
Colonies consist of one to several hundred queen ants, sterile
female worker ants, periodically produced winged male and female
reproductive ants (sexuals) and brood (develop-mental stages).
These ants do not swarm. Colonies multiply by “budding,” in
which a large part of an existing colony migrates carrying brood
to a new nesting site. |
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Carpenter Ant |
Fourteen species of carpenter ants live in Texas. The largest,
the black carpenter ant, Camponotus pennsylvanicus, is found
primarily outdoors in wooded areas. Common indoor species,
Camponotus rasilis and C. sayi, have workers with dull red
bodies and black abdomens. Worker ants range from 1/4 to 1/2
inch long. They can be distinguished from most other large ant
species by the top of the thorax, which is evenly convex and
bears no spines. Also, the attachment (pedicel) between the
thorax and abdomen has but a single flattened segment. Although
these ants bite, they do not sting.
Foraging worker ants in the home can be a nuisance. Carpenter
ants usually nest in dead wood, either outdoors in old stumps
and dead parts of trees and around homes (in fences, firewood,
etc.) or indoors (between wood shingles, in siding, beams,
joists, fascia boards, etc.). Ant colonies are often located in
cracks and crevices between structural timbers, but the ants can
also tunnel into structural wood to form nesting galleries,
although this is less common in Texas. They seem to prefer
moist, decaying wood, wood with dry rot or old termite
galleries. However, damage is often limited because these ants
tunnel into wood only to form nests and do not eat wood.
Galleries excavated in wood to produce nesting sites can weaken
structures.
Occasionally carpenter ants, particularly Camponotus rasilis,
nest under stones or in other non-wood cracks and crevices.
Foraging worker ants leave the nest and seek sweets and other
foods such as decaying fruit, insects and sweet exudates from
aphids or other sucking insects.
Nesting tunnels when produced by carpenter ants usually follow
the grain of the wood and around the annual rings. Tunnel walls
are clean and smooth. Nests can be located by searching for
piles of sawdust-like wood scrapings (frass) under exit holes.
These piles accumulate as the nests are excavated and usually
also contain parts of dead colony members.
Life cycle: Eggs develop from egg to worker ant in about two
months. Carpenter ants are social insects, living in colonies
made of different forms or “castes” of ants. Mature colonies
contain winged male and female forms (reproductives), sterile
female workers of various sizes, and a wingless 9/16-inch-long
queen. Winged forms swarm during May through late July. The
presence of 3/4-inch-long winged forms in the home indicates
that a colony is living indoors. |
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Other Ants |
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Other ant species occasionally encountered in and around the
home include:
• Acrobat ants, Crematogaster sp., which nest under stones, in
stumps or dead wood, and occasionally invade the home. Some
species make carton nests in trees. These ants often hold their
heart-shaped abdomen up over their bodies. They feed primarily
on honeydew produced by aphids.
• Argentine ants, Iridomyrmex humilus, whose workers are light
to dark brown and generally nest outdoors. They are uncommon in
areas infested by fire ants.
• Bigheaded ants, Pheidole species, whose major worker ants have
relatively large heads compared to their bodies. They have
12-segmented antennae with a three-segmented club. Similar in
habits to fire ants, they feed on live and dead insects, seeds
and honeydew outdoors and greasy food sources and sweets
indoors.
• Crazy ants, Paratrechina longicornis, whose fast-running,
grayish-black worker ants have long legs and antennae. Although
they nest primarily outdoors, they will forage in homes. They
are omnivorous, but difficult to attract to ant baits.
• Little black ants, Monomorium minimum, small, slow-moving,
shiny black ants. Workers prey on insects and feed on honeydew
produced by sucking types of insects such as aphids. |
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Preventive
Measures |
Ant problems occur in homes and structures
primarily because food, water and favorable nesting sites are
available there. Meticulous housekeeping eliminates significant
ant problems by removing needed resources. Furthermore, ant bait
treatments are more effective if alternative food sources for
the ants are eliminated as much as possible.
Most ants prefer to nest in soil or wood outdoors, but homes
offer many favorable nest sites for certain ants. Cracks and
holes in brick veneer, wall voids and structural wood close to
heat and moisture sources are commonly used. Reduce water
sources and nesting sites by caulking cracks and crevices,
fixing leaks and replacing wet or rotten wood. Pay particular
attention to ant colonies infesting potted plants or fire wood
brought indoors. |
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Treatment |
Insecticides registered for ant control are
formulated as liquid sprays, dusts, fogs and baits. Many are
generally labeled to control “ants,” although some are
specifically registered for particular ant species.
The most effective ant control is to find the nest and treat it
with insecticide. An alternative is to use the workers to carry
an insecticidal bait back to other colony members. In the home,
extensive, undirected insecticide treatments, such as ant trail
treatments or total-release aerosol fogs, are usually
unsatisfactory because they kill only a few workers and often do
not greatly affect the colony, the source of workers. Using
surface applications on ant trails actually can make Pharaoh ant
colonies divide and make the infestation worse! When home
control attempts fail, seek help from a licensed commercial pest
control operator. |
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