"Carpenter Ants" (Camponotus spp.)

These long-legged, swiftly-moving creatures are among our largest ants which may occasionally invade homes foraging for food or for nest building. The workers are highly polymorphic, that is they vary greatly in size ranging from 1/4 inch to more than 3/8 inch. The queens may be more than 1/2 inch long. The black carpenter ant, Camponotus pennsylvanicus, is the most common carpenter ant in the eastern states. It is a dull black color with an abdomen covered with long yellowish hairs pressed against the body surface. Foraging workers may be from 1/4 to 1/2 inch or more in length. Other common eastern species include the red carpenter ant, C. ferrugineus, and the Florida carpenter ant, C. abdominalis. Although found in much of the eastern United States, C. rasilis, is probably one of the most common species encountered in the Gulf Coast states. Its head, thorax and petiole are reddish and the gaster is black. Worker size varies from 4 to 9 mm long. A species found throughout the United States is C. nearcticus, which is smaller with the workers being 4.5 to 7.5 mm long.

Carpenter ants, because of their large size and biting ability, attract more than a passing glance from even the neophyte nature lover. It is a common experience of hikers, who seek the comfort of a woodland log, to find themselves suddenly beset by large numbers of these biting ants. Carpenter ants are distributed widely throughout the United States and range from sea level to well above 9,000 feet in the western mountain ranges. They very often are pests in lawns as well as homes. Since theirs is the habit of dwelling in and excavating wood, they were given the common name of "carpenter ant."

The colony is ordinarily initiated by one queen, who begins the nest beneath a rock or in the soil, or in an insect-bored tunnel in a tree, etc. The queen lays only a few eggs and these hatch into very small workers. The minims or small workers then go forth to forage. The small workers then feed the young and the queen, whose sole interest in life is the production of eggs. If the enviroment is propitious, the colony thrives. The pupae are closed in cocoons, which are referred to by most individuals as "ant eggs." When the nesting site is in wood, it often resembles an ornate carving due to the multiplicity of the galleries. These galleries are so smooth, they appear to have been sandpapered. The carpenter ants ordinarily excavate that portion of the wood softened by decay or by the attacks of other insects. However, Fowler (1986) stated that carpenter ants are more often found in sound wood than rotten wood.

Pricer (1908) made a detailed study of the life history of the black carpenter ant in Illinois at a temperature of 70 to 90 degrees F. The female laid 22 eggs in 15 days. The eggs stage took 24 days, larval stage 21 days and pupal stage 21 days (66 days from egg to adult). Under natural conditions, the larval stage may be of much longer duration during the winter. The winged sexual forms were observed to emerge about the first of July. Large colonies may be characterized by winged males and females during the winter. The colony does not produce the winged forms until it is more than two years old. These winged sexuals, which may be produced during one summer, overwinter in the parental nest and emerge for their marriage flight from May to July. One colony had as many as 3,212 worker ants.

Blake (1940) notes there may be more than one queen in a colony and the largest workers may lay eggs which only produce male ants. "After mating, the queen makes or finds a smaller chamber in which she remains, sealed up, until her first brood of workers is adult. This requires at least two months and sometimes as long as 10 months." Most of the work of the carpenter ant is done by smaller workers.

Anon (1959) reports these ants are able to withstand cold because they generate glycerol in their bodies whenever the temperature falls below a certain point. This is nature's way of manufacturing "antifreeze." The addition of triglycerides occurs with many other insects including several stored product insects.

Ants of the genus Camponotus apparently have better eyesight than ants of most other genera. Consequently, they are successful hunters. The carpenter ants also attend aphids and other honeydew-secreting insects.