Ant Information, Prevention & Treatment
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.
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.
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.
Rasberry Crazy Ant
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.
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.
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.