The black carpenter ant is a native species. These wood destroying insects get their name from their habit of hollowing out galleries in pieces of wood for nesting purposes. This nesting habit can result in structural damage. Carpenter Ants are found throughout the United States. They are black with three distinct body parts and segmented antenna. The workers are about 1/4" to 1/2" (6-13mm) long, with the queen 1/2" to 5/8" (13-17mm) long.
Black carpenter ant colonies usually contain over 3,000 workers when nest is mature and up to 10-15,000 including satellite nests. There is usually only one functional, wingless queen per colony. Swarmers (carpenter ants with wings)are not produced until the colony is more than two years old, usually 3-1/2 to 4 years old. Swarmers appear from May until August in the east and February through June in the west.
Carpenter ant nests are usually started in decayed wood and later expand or enlarge this into sound wood. Nests are located in wood, preferably soft wood, in insulation, and/or in wall voids. The presence of a nest is sometimes indicated by a rustling sound coming from wall voids or from wood where a nest is located. Otherwise, the emergence of swarmers indoors may be the first indication of an indoor colony.
The workers forage for distances of up to 300 feet from the nest. They typically enter buildings around door and window frames, eaves, plumbing and utility lines, and tree or shrub branches in contact with the building.
The first step for control is to determine if the ants present are merely foraging inside or if there is a nest inside. The best indication of a nest is the presence of sawdust piles containing insect body parts. Another indication is the sound produced as the workers remove wood to expand the nest. Check outside around the building's perimeter for foraging trails between trees and shrubs to the foundation. The trail between the parent and satellite nest is usually about 1/4" to 3/4" (6-20mm) wide and is kept clean of vegetation and debris.
Check crawl spaces, basements and attics. Carpenter ants have a network of trails they follow throughout a structure and often use the tops of electrical wires and water pipes so be sure to check where these are. Detection of a trail directs one to the parent colony. For effective control, it is imperative to locate and eliminate the parent colony. Once the colony or colonies are located, they should be treated directly with an appropriately labeled pesticide.