Carpenter Ant Frass - UNL Dept of Entomology

Carpenter Ants (Camponotus, spp.)

Black Carpenter Ant
Camponotus pennsylvanicus
Red Carpenter Ant
Camponotus sayi

Black Carpenter Ant Actual SizeDescription of Workers: Medium to large workers, 1/4-inch to 1/2-inch. Thorax evenly rounded. Colonies have workers that are not all the same size (polymorphism). Black carpenter ants are most common species in Nebraska.

Camponotus sayi

Red Carpenter AntDescription of Workers: Workers of a second carpenter ant species, C. sayi have reddish-brown head and thorax and black abdomen. It is unofficially called the "red" carpenter ant to distinguish it from the black species. These ants are about 3/16-inch to 1/4-inch long.


Both species of Carpenter ants nest in wood and are often associated with moisture problems. In structures, they are often found where water has leaked and soaked the surrounding wood, around plumbing, under windows, in soffits, where the roof has leaked.

Contrary to popular belief these ants DO NOT eat wood. The diet of carpenter ants includes living and dead insects, honeydew from aphids, sweets, meat, and fats.

Carpenter ants use their strong mouthparts to tunnel wood to make galleries. This resulting sawdust looks like fine wood shavings, but is not powdery. It may contain foam insulation.

Workers of C. pennsylvanicus (black carpenter ants) can travel 300 ft from colonies so carpenter ants inside do not necessarily mean there is a colony within the structure.

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 sound like crinkling cellophane as they move about in their colony. A stethoscope may be helpful in finding colonies within a wall.


Management involves eliminating moisture problems associated with interior colonies to correct conditions suitable for colony survival. Treatment involves locating and appropriately treating colonies. Insecticidal dusts are often used in wall voids because liquid insecticides soak into wood and may not spread throughout wall voids so ants will track the dust back to the colony. It may be desirable to hire a pest control professional who has appropriate equipment and expertise to treat wall voids. Colonies can sometimes be eliminated by discarding infested wood or by vacuuming ants. In these situations, no insecticides may be needed.

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This resource was updated November 2015 by Soni Cochran, Extension Associate

Credits: Ant illustrations were developed by Vicki Jedlicka, Nebraska Extension in Lancaster County

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