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Carpenter Ants

ORDER: Hymenoptera GENUS: Camponotus
FAMILY: Formicidae SPECIES: pennsylvanicus

Definition. Carpenter ants are found throughout the world, and there are many different species. The Black Carpenter Ant, Camponotus pennsylvanicus, was named by science in 1773, and was the first North American ant to be named. It occurs throughout the eastern United States and southeastern Canada.

Life Cycle. Winged males and female carpenter ants engage in a nuptial flight in late spring and early summer. Mating occurs in midair, after which the queen loses her wings, locates or excavates a small cavity in wood, and seals herself in the chamber, remaining alone until her first brood develops into adult workers. At first, the queen lays but a few eggs, which hatch into tiny workers. She feeds the workers with her salivary glands until they are able to forage for food. When reaching adult stage, the workers build and maintain the nest.

Three to six years are required to develop a large colony of carpenter ants. Only the first brood is reared by the queen. Further broods are fed and cared for by the workers. Workers will cut galleries to enlarge the nest as the colony grows. After three years or more, winged males and females are produced, and they engage in nuptial flights.

Damage. Millions of dollars are spent annually to control carpenter ants in the United States. There has been conflicting information regarding whether or not carpenter ants attack new, undamaged wood. Current information has shown that colonies are first established in pre-existing cavities, usually in faulty or rotten wood, then expand into both rotting and undamaged adjacent wood around such cavities. They do not eat wood or tunnel through wood structures as do termites. Damage is local, caused by enlargement of the nest. Colonies may be composed of thousands of workers of various sizes, winged reproductive forms, and immature ants. Homeowners may see individual ants, but may also note the presence of carpenter ants by finding a pile of coarse sawdust, commonly mixed with ant and other insect parts, on the carpet or other floor surface in the house. Carpenter ants do not usually bite humans, but their jaws are large and capable of inflicting a painful bite. Carpenter ants do not sting.

Habits. Workers are omnivorous, and will attack live arthropods as well as scavenge on dead arthropods for proteins. Honeydew is gathered from aphids and similar plant-sucking insects. Flowers and fruits are visited also for a food source. Many feed on household foods in homes. There are different food preferences during the active season, related to activities of the colony.

Control. Because the black carpenter ant has different food preferences during the season, a good control agent bait should include both proteins and carbohydrates. The alternative would be to have two different control agent baits, one with proteins in the spring, and one with carbohydrates later in the year. Baits must be placed where ants will find them. When ants enter man-made structures that are near their supply of wood, the entry sites, often cracks in a structure, should be repaired to stop such an invasion. Ants commonly enter a structure by following utility lines. Carpenter ants prefer to nest in weathered and decaying soft wood; thus, control should include elimination of high moisture conditions and rotten wood. Also keep food areas clean, which eliminates a food source.

Selected References:

Akre, R. D. & Hansen, L. D. 1990. Management of carpenter ants, pp. 693-700. In R. K. Vaneder Meer, K. Jaffe & A. Cedeno [eds.], Applied myrmecology, a world perspective. Westview, Boulder, CO.

Klotz, J. H. , Reid, B. L. , & Klotz, S. A. 1996. Trailing the Elusive Carpenter Ants: A key to its control. Amer. Entomologist, Volume 42, Number 1, pages 33-39.

Smith, M. R. 1965. House Infesting Ants of Eastern United States: Their Recognition, Biology, and Economic Importance. Tech. Bull. No. 1326, U.S. Department of Agriculture, Washington, D. C. 105 pp.

Snyder, T. E. 19S7. The Carpenter Ant. Terminix Technical Paper #3, published by E. L. Bruce Co., Memphis, 4 pages.

 

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Information Sheet Number 23.

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