Great Gray Owl Pest Control

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Carpenter Ants


Camponotus spp.:

Carpenter ants are most active at night, emerging after dusk and returning to their colony prior to dawn. Some foraging occurs during the day. Carpenter ants make noise that sounds like crinkling cellophane as they move about in their colony. 

For a quote for carpenter ant service, telephone 705-426-1903 or toll-free 1-877-882-4403, or email


  • 13 to 15mm long
  • brown or black 
  • larger than the rest of the colony
  • bites off wings after mating
  • the only ant in the colony that lays eggs


  • 6 to 10mm long (black carpenter ant workers are up to 1/2" long  and red carpenter ant workers are up to 1/4" long)
  • brown or black
  • wingless
  • sterile females
  • have mandibles for chewing (workers do the damage in homes)


  • 6 to 10mm long - larger than workers
  • large, strong mandibles
  • wingless
  • large heads

Black Carpenter AntCarpenter ants are among the most conspicuous of ants. Large and prone to biting humans, the workers vary greatly in size from 6 to 10 mm long and are usually black but may have some brown or red coloration. Various species occur throughout North America including the following most commonly seen in Ontario:

C. pennsylvanicus known as Black Carpenter Ant

C. sayi known as Red Carpenter Ant




Nesting Habits

Carpenter ants excavate galleries in wood that somewhat resembles the work of termites, but are distinguished by a clean, sandpapered appearance that contains no debris. Usually found in unsound or moisture-damaged wood, carpenter ant nests may also occasionally be found in sound, dry wood. They do not eat the wood, but hollow it out only for nesting. The presence of a colony is sometimes first noticed because of the habit of the worker ants of dropping sawdust-like debris (frass) from wherever the excavation is being made.

Red Carpenter Ant

Carpenter ants will establish nests in a number of different locations. Outdoors, the site selected may be in a stump, hollow log, telephone pole, fence post or similar large pieces of wood. Wood that is moist or partially decayed is preferred although cracks, crevices and other cavities may be used to get a nest started in sound wood. Ants can be carried indoors in firewood. Often, ants move into a building solely to feed. However, nests do occur indoors and may be found in hollow doors, window sills, the sub-structure of porches, roofs, behind baseboards, fireplaces, shingles or other natural hollow areas. The nest may also be just a hollow pipe with several hundred ants in it. Carpenter ants also show a preference for nesting in styrofoam insulation.

If the nest is in wood, the ants cut galleries with the grain and follow softer areas of the wood. The galleries are smooth and clean, hence the name "carpenter" ant. Some of the harder layers of wood often remain as walls separating the many tunnels. At frequent intervals, openings are cut in these walls, providing a means for movement from section to section. Access to the outside may be through natural cracks or openings in the wood. Sometimes, however, the ants cut special openings which are called "windows".

The occupied galleries are kept immaculately clean. Shredded wood fragments resulting from the excavations are carried from the nest and deposited outside. Conical piles of these wood fragments, bits of soil and sand, portions of insect, dead ants and other debris sometimes build up beneath the "windows" or other openings to the nest. this "sawdust" is not always evident, as the ants may dispose of it in a hollow portion of a tree, void areas in a structure or unused galleries within the nest.

Swarming and Reproduction

The winged reproductive forms swarm in the spring at which time new colonies are established. Once the colony begins to mature, several sizes and forms of ants will be found in the nest. There is usually only one queen, but many workers of various sizes are present. The workers are sexually undeveloped females. In general, the larger ones guard the nest, battle intruders, explore and forage for the young. However, these duties do overlap, and some members of each caste are engaged in all occupations.

The colony is considered mature when winged reproductives are formed. this occurs in 3 to6 years at which time the colony may contain 2,000 to 3,000 or more individuals. It is unlikely that there is any increase in numbers thereafter due to the constant drain of the many swarmers produced each year.

The winged male and female forms may be produced at any time but they usually develop in late summer. After spending the winter in the nest, they swarm in the spring or early summer. From 200 to 400 winged individuals are produced each year in a mature colony.

Feeding Habits

The carpenter ant diet includes a great variety of both animal and plant foods. The ant will feed on other insects both living and dead, and anything humans eat. Honeydew is a sweet food produced by aphids that is particularly attractive to carpenter ants. Many sweets and meats found in kitchens and storage areas are fed upon including syrup, honey, jelly, sugar, meat, grease and fat.

The foraging workers collect all of the food for the colony. Sometimes carpenter ants will travel up to 100 yards from the nest for food and will wander throughout a house in search of food. The workers do not lay down the scent trails used by some of the other ants, and as a result, workers are found scattered about with no particular trail leading to the nest. The food collected may be carried back to the nest, but more often it is ingested where it is found. Later, it is regurgitated in the nest for use by the queen, developing larvae and the nonforaging workers.

Economic Importance

Carpenter ants are a major pest of economic importance because of the damage they do to structures, the food they contaminate and their unsightly and unwanted movement inside and outside of buildings. Their nesting activities do weaken building structures, although not usually as seriously as termites.