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Carpenter ants

Carpenter ants

Carpenter ant castes.

Figure 1. Carpenter ant castes – left column winged female (top), winged male – right column – workers of varying sizes.

Carpenter ants are among the largest ants in New York. 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 ½ inch. Winged queen ants may be as large as one inch.

A colony of ants are divided into different castes: i.e. workers, queens, and males (figure 1). Some ants, including carpenter ants, have different sized workers which help the nest with a range of jobs from food collecting to nest defense. The best method to distinguish 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.

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. These ants are usually not wood-infesting, so it is important to correctly identify the ants before control is attempted, as effective control strategies vary with different ant species.

Carpenter ant worker.

Figure 2. Carpenter ant worker. Note the evenly rounded thorax and the one segmented petiole.

Ant or termite?

Carpenter ants differ from termites in that they have dark-colored bodies, narrow waists, elbowed (bent) antennae, and – if wings are present – hind wings that are shorter than front wings (figures 3 and 4). Carpenter ants are very common and are frequently seen in the open, especially after sunset.

Illustration of winged carpenter ant.

Figure 3. Winged carpenter ant.

Winged carpenter ants.

Figure 4. Winged carpenter ants.

Termites are light-colored, have a broad waist, have straight antennae and, if present, wings are of equal length (figure 6 and 7). Termites are rare to very uncommon in New York. They avoid light and are rarely seen outside of their colony, except when winged reproductives, called kings and queens, leave a termite colony.

Illustration of winged termite.

What they eat

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 and pet food, 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 for nesting.

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. It is during this search that they may get into houses by searching along the foundation or along a tree branch that is touching the roof. Carpenter ants also interact with our houses when they travel back and forth between their main nest, which must be persistently damp and thus is usually outdoors, and their satellite nests, which may be on the outside surfaces of houses (porches, decks, etc.) or may be in walls, doors or other hollow spaces indoors (see explanation below).

Where they live

Photo of damage caused by carpenter antsFigure 5. Carpenter ant damage in a stump.

There are two types of carpenter ant nets: parent colonies and satellite colonies. Parent colonies are typically established outdoors in moist wood including rotting trees, tree roots, tree stumps, and logs or boards lying on or buried in the ground. They may also nest in moist or decayed wood inside buildings. Wood decay may be caused by exposure to water 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. Areas around windows and where wood parts touch the foundation may be prone to infestation. Carpenter ants may also nest in foam insulation.

Parent carpenter ant colonies sometimes establish one or more satellite nests in nearby indoor or outdoor sites. Satellite nests are typically composed of workers, pupae, and mature larvae. A satellite nest with less moisture may only support workers (the eggs would dry out in lower humidity). For this reason, satellite nests can be found in relatively dry locations, such as insulation, hollow doors, sound wood, and wall voids. 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. Carpenter ants may move eggs into satellite nests inside a house or other structure if there is enough moisture.

Carpenter ant damage.

Figure 6. Carpenter any damage in header boards.

Damage

Carpenter ants damage wood by excavating and creating galleries and tunnels for their nest. These areas are clean, i.e. they do not contain sawdust or other debris, and are smooth, with a well sanded appearance .

The damage to wood structures is variable. The longer a colony is present in a structure, the greater the damage that can be done. Structural wood can be weakened when carpenter ant damage is severe.

When you discover these creatures in or around your home contact a professional immediately to stop the damage and eradicate the source.