Carpenter Ants

Common Name: Carpenter ant
Scientific Name: Camponotus sp.
Order: Hymenoptera Description: Fourteen species of carpenter ants occur in Texas. The largest species is the black carpenter ant, Camponotus pennsylvanicus (Fabricius) and is found primarily in wooded areas outdoors. Common indoor species, Camponotus rasilis Wheeler and C. sayi Emery, have workers that are dull red bodied with black abdomens. Worker ants range in size from 1/4 to 1/2-inch. They can be distinguished from most other large ant species because the top of the thorax is evenly convex and bears no spines. Also the attachment between the thorax and abdomen (pedicel) has but a single flattened segment.

Winged reproductive carpenter ants should not be confused with winged termites (Isoptera). Ants have elbowed antennae, distinctly veined wings of different sizes (large forewings and small hind wings) and a narrow portion of the body (waist) between the thorax and abdomen. The acrobat ants, Crematogaster sp., also occasionally nest in wood. These ants are much smaller and have a heart-shaped abdomen that is often held up over their bodies. They feed primarily on honeydew produced by aphids (Homoptera).

Life Cycle: Ants develop through several stages: eggs, larva, pupa and adult. Larva are legless and grub-like and pupae are a cream-colored to tan cocoon which are often mistakenly called “ant eggs.” Development from egg to worker ant occurs in about 2 months. Carpenter ants are social insects and live in colonies made of different forms of ants or “castes.” 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 is an indication that structural damage may be occurring.

Habitat, Food Source(s), Damage: Mouthparts are for chewing. These ants usually nest in dead wood, either outdoors in old stumps and dead parts of trees and around homes (in fences, fire wood, 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. They often appear 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 (nesting tunnels) 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) underneath exit holes. These piles accumulate as the nests are excavated and usually also contain parts of dead colony members. Occasionally carpenter ants, particularly Camponotus rasilis Wheeler, nest under stones or in other non-wood cracks and crevices. Foraging worker ants leave the nest and seek sources of sweets and other foods such as decaying fruit, insects and sweet exudates from aphids or other sucking insects.

Pest Status: Although these ants can bite, they do not sting. Galleries excavated in wood by carpenter ants to produce nesting sites can weaken structures.  Foraging worker ants in the home can be a nuisance.    Link…


Carpenter ants are among the largest ants in Minnesota. There are several species of carpenter ants that may be found infesting homes and other buildings. Normally workers are black or red and black in color and range in size from 3/8 to 1/2 inch. Winged queen ants may be as large as one inch. However, size is not a reliable characteristic to identify carpenter ants. The workers of one species in Minnesota are no larger than 3/16 inch.

carpenter ant castesFigure 1. Carpenter ant castes, from left to right: queen, winged male, major worker, minor worker
carpenter ant workerFigure 2. Carpenter ant worker

non-carpenter and workerFigure 3. Typical non-carpenter ant worker

Ants are divided into different castes, i.e. workers, queens, and males (figure 1). Some ants, including carpenter ants, have polymorphic workers, which means that within one species the workers occur in different sizes. The best method to separate carpenter ants from other ants is by the following characteristics: 1) a waist with one node (petiole) and 2) a thorax with an evenly rounded upper surface (figure 2).

There are other ants that appear similar and are occasionally mistaken for carpenter ants. They may have one or two nodes. However, they can be distinguished from carpenter ants by the uneven profile of their thorax (figure 3). These ants are usually not wood-infesting, so it is important to correctly identify the ants before control is attempted as control strategies vary with different ant species.

Carpenter ants feed on sources of protein and sugar. Outdoors, carpenter ants feed on living and dead insects. They are also very attracted to honeydew, a sweet liquid produced by aphids and scale insects. Aphids and scales feed on trees, shrubs, and other plants. Indoors, carpenter ants feed on meats, as well as syrup, honey, sugar, jelly, and other sweets. Carpenter ants DO NOT eat wood. They remove wood as they create galleries and tunnels.

Most foraging is done at night between sunset and midnight during spring and summer months. Sometimes workers travel up to 100 yards from a nest in search of food.

Carpenter ants nest in moist wood including rotting trees, tree roots, tree stumps, and logs or boards lying on or buried in the ground. They can also nest in moist or decayed wood inside buildings. Wood decay may be caused by exposure to leaks, condensation, or poor air circulation. Nests have been found behind bathroom tiles; around tubs, sinks, showers, and dishwashers; under roofing, in attic beams, and under subfloor insulation; and in hollow spaces such as doors, curtain rods, and wall voids. Carpenter ants may also nest in foam insulation.

A parent carpenter ant colony sometimes establishes one or more satellite nests in nearby indoor or outdoor sites. Satellite nests are composed of workers, pupae, and mature larvae. A satellite nest does not require moisture because the workers do not tend eggs (the eggs would dry out without sufficient humidity). For this reason, satellite nests can be found in relatively dry locations, such as insulation, hollow doors, and sound wood. The workers of satellite colonies move readily between their nest and the parent colony. In late summer, winged reproductives (i.e. queens and males) may emerge from pupae transported into satellite colonies. They may appear in structures in late winter and early spring as they swarm from a satellite nest.    Link…

Note:  We don’t need to destroy ants as to kill them when they cause damage  to properties; but we can think of another way to drive them out from our homes.

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