Carpenter ants are among the largest ants found in the United States, ranging from 1/8 to ½ inch long, the queens are slightly bigger. The workers of an established colony vary in size. They are commonly black; however, some species are red and black, solid red, or brown in color. They have one node in the petiole and a circle of tiny hairs on the top of the abdomen. Their thorax is evenly rounded when seem from the side.
The adult winged female or queen loses her wings soon as mating with the smaller male and selects a secluded nesting site where she raises the first brood of workers. These workers are very small but assume the care of the larvae and the queen after they mature. Future workers are larger than those from the first brood because they receive better care. All workers are wingless.
Mature colonies range in size from several thousand workers to an average of 20,000. When raised at 90°F, black carpenter ants complete their life cycle (egg to adult) Swarmers do not appear in the colony for several years, usually from three to four years up to six to ten years. Swarming for these species occurs May through August and February through June, respectively.
Carpenter ants are social insects that usually nest in wood. They commonly excavate galleries or tunnels in rotting or sound trees and, in structures, readily infest wood, foam insulation, and cavities. They prefer to excavate wood damaged by fungus and are often found in conjunction with moisture problems.
The workers excavate the nest, forage for food, and care for the young. Carpenter ants feed on sugar solutions from honey dew-producing insects such as aphids, sweets, and the juices of insects they capture. They do not eat the wood as they excavate their nests. They actively feed at night well after sunset continuing through the early morning hours. Foraging may extend up to 300 feet and, upon close inspection, can be seen on the ground as narrow worn paths.
Carpenter ants enter structures through gaps or cracks while foraging for food. However, the appearance of large numbers of winged adults inside a structure indicates that the nest(s) exists indoors. The workers push wood shavings and pieces of foam insulation out of the nest through slit-like openings in the surface of the wood or other nesting site material. This material, which may contain fragments of other insects, and structural moisture problems are things to look for when trying to locate a colony in an infested structure. Rustling sounds in wall voids are another indication that there is a colony in the area.
Carpenter Ants Questions and Answers
I see these big black ants in my house, what are they?
They are most likely carpenter ants. Workers inside a house is an indication that a portion or satellite colony is living in the walls. A satellite colony is a group of ants belonging to a much larger colony containing workers and some larvae (young ones). The rest of the colony is living outdoors in trees, logs, firewood piles, or other wooden structures such as detached garages, fences, etc.
Where are carpenter ant nests found?
Common areas includes the porch pillars and supporting timbers, sills, girders, joists, wall studs, window and door casing, and underneath the insulation in the attic, ceiling joist, and wall studs. Areas where leaks have recently taken place is a prime are to look for the nest. Wet areas due to poor ventilation, defective flashing, overgrowth of vegetation up against the structure, leaky gutters and downspouts, condensation from pipes, around bathtubs, showers, and appliances are also common locations.
So, do I need to get rid of them, if so how?
Try to find the nest - carpenter ants are most active at night. Use a flashlight to follow foraging workers back to the nest site. This may take some time. Look for the frass (wooden shaving and debris) that is expelled from the nest. Hiring a pest professional may be required to locate the nest and eliminate them using the latest materials or least toxic materials. Dust is an excellent tool to flush out and eliminate nest sites in the various locations mentioned above. Bait is also very effective early in the season (late winter or early spring) before their natural food sources become available. They are less effective during the summer months when a variety of food sources are found. Pest professional also have available non-repellent formulations that are very effective against carpenter ants.
How do I prevent carpenter ants from returning to my home?
The parent and satellite colonies must be found and eliminated, otherwise the carpenter ants will be back. Repair any structural damage found. This may include sealing around windows and doors, replacement of damaged wood, etc. Eliminate any leaks around windows or from plumbing quickly and dry the area.