Carpenter Ants


Camponotus spp.


Carpenter ants occur widely in the United States, with 42 known species. Eighteen of these species occur in Texas. The adults vary in length from 1/4 inch for small workers to 1/4 inch for a queen, and the color varies from dark brown to red to black. In Texas some species are both red and black. Most colonies have workers of several sizes (polymorphism). They do not sting, but have a strong bite with their mandibles

Carpenter ants seek out soft, moist wood in which to establish their nests; they particularly prefer wood that has weathered and begun to decay. Although the nest is most often begun Carpenter ants-winged tin the soft wood, later excavations frequently are made into perfectly and two workers sound, dry lumber. Carpenter ants can be found in porch columns and roofs, window sills, hollow core doors, wood scraps in dirt-filled slab porches, and wood in contact with soil.

An infestation in a building may be started by a single fertilized female. However, many times it is started by a colony or portion of a colony moving in from another location. This is especially true in wooded areas. The queen sheds her wings when the new colony is started and remains wingless the rest of her life. The males are winged and die soon after the mating flight is over. Winged forms are usually not produced in a colony until it is at least three years old. A large colony can cause serious structural damage if not controlled.

Carpenter ants do not eat wood (in contrast with termites), but excavate galleries in the wood in which to rear their young. Carpenter ants eject the wood in the form of a coarse sawdust. The characteristic sawdust piles aid in nest location. They feed on honeydew excreted by aphids, and upon other insects, animal remains, and household food scraps. They are particularly fond of sweets. Despite this, it is difficult to use a bait material to control carpenter ants; treatment of the colony with a liquid insecticide or dust is often more successful.

The damage of carpenter ants is easily distinguished from that of termites. Their galleries are excavated without regard for the grain and follow the softer portions of the wood. The galleries are kept smooth and clean and have a sandpapered appearance. Termite galleries are not smooth and clean.

When carpenter ants are found within a structure, the colony is either nesting within the building or nesting outside the building and entering to forage for food. Houses near wooded areas are especially subject to invasion.

The key to the control of carpenter ants is locating the nest or nests, which is often difficult. If the nest or nests can be found, there is an excellent chance of controlling this pest. Eliminating nests outside may be just as important as eliminating those in buildings. In some cases, an entire colony may migrate from one nesting site to another-from a tree outdoors to structural timbers indoors.

To find nests indoors, examine these locations:

  • Wood affected by water seepage (porch floors, roofs, porch posts and columns)
  • Wood in contact with the soil.
  • Wood adjacent to dirt-filled slab porches.
  • Firewood piled in garages or next to a house.

Carpenter ants are usually found near moisture. Some signs of carpenter ants to look for when inspecting for a nest indoors are:

  • Piles of coarse "sawdust" on the floor or foundation.
  • Ant activity, particularly in kitchens. However, even when the nest is in a building very few ants may be seen. They are usually active at night and often forage outdoors.

Some of the things to look for outdoors are:

  • Firewood, stumps, logs and trees that might contain nests.
  • Trees with branches hanging over and touching the roof of a house. Ants may travel over these branches into the building.
  • Power and utility lines leading to the house, particularly if they pass through trees and shrubs.

Sanitation measures such as removing and destroying logs and stumps that harbor nests will help eliminate the pest. To protect structures from carpenter ants, destroy the nests in and near the structure.