Pest Identification

Size:
Worker size varies between 1/8-1/2 in (3.5-13 mm) long; queen may be up to 5/8 in (17 mm) long.

Color:
The common western species is dull black with reddish legs and golden hairs covering the abdomen. Other species are black, a combination of red and black, or completely red or brown.

Where found:
Throughout the United States. The black carpenter ant is common in the east, the western carpenter ant in the west.

Habitat:
Carpenter ants hollow out spaces in wood to use as nests. Most species nest first in decayed wood and then enlarge the nest into sound wood. Indoors: nests are in wood (perhaps softened by fungus rot), insulation, wall voids. Outdoors: nests are in old firewood, rotting fence posts, stumps, dead portions of living trees, under stones and logs. A colony has a main nest connected to satellite nests by a cleared trail about 1/4 inch wide.

Food:
Outdoors: plant juices, insects, and honeydew from insects, spiders. Indoors: sweets, grease, meat, and eggs. Carpenter ants follow a regular trail when foraging.

Biology:
A mature colony of western carpenter ants may have 10,000-20,000 workers, or up to 100,000. Swarmers aren't produced until the colony matures. In the West, swarmers may appear between February and June. There is usually just one functional, wingless queen per colony. Development from egg to adult takes at least 60 days. 

Damage:
Hollowing of wood for nests can weaken a structure. Also, bites can be painful.

Invasion:
Carpenter ants enter near doors and windows, pipes, utility wires, and branches of trees or shrubs.