NPIPM:Camponotus spp.
Authors: Ashley Mueller, Buyung Hadi
Ants are one of the most common pests that can be found in and around homes. Ants are social insects, and they live together in colonies. They are divided into three classes called castes: queens, males, and workers. Each caste serves the colony in specific way. Queens lay eggs and care for the brood; males play a vital role in reproduction; and workers provide food to the colony by foraging. Ants use pheromones to create invisible odor trails. The workers follow the odor trails to and from the nest while foraging for food. Indoors, ants are often seen following trails.
Although ants can be a nuisance, they can also contaminate food, wreak havoc on yards, and cause structural damage to buildings. There are many ways homeowners can prevent ants from coming indoors. Identifying problematic ants is essential in determining how an infestation is managed.
Identification
Carpenter ants are among the largest ants in North America. Worker carpenter ants are about 1/4 to 1/2 inch long, and they are black to reddish brown in color. A diagnostic characteristic is a smoothly rounded chest region, the thorax, when viewed from the side. A single node (a triangular structure) on the pedicel, the stem structure relating the abdomen to the thorax, is another diagnostic characteristic.
Habitat
Carpenter ants excavate wood, including structural wood in a building, to nest. The larger parent nest can typically be found outdoors in a dead tree stump or a living tree while indoor nests serve as satellite nests. There may be several satellite nests to one parent nest. Indoor nests can be found in structural wood, roof eaves, porches and decks, around and under windows, and even inside stored furniture. Carpenter ants feed on sources of protein, such as dead or living insects, and sugar. They do not eat wood.
Life Cycle and Seasonal History
A single queen, after mating, will locate a suitable nesting site, where she lays a small amount of eggs. In 2-3 weeks, the eggs hatch into larvae, and the queen cares for the larvae. The larvae become the colony’s first workers. Colony growth is slow at first. While the queen continues laying eggs, the first workers search for food and provide care for the colony. Each colony has at least one queen.
Carpenter ant workers are different sizes. Larger ants and smaller ants perform different work for the colony. After several years, when a colony has matured, it may produce winged colony members called swarmers during late summer. These swarmers, identified by the presence of wings, are reproductive queens and males. Once grown, swarmers will typically emerge in the spring to locate new sites suitable for a nest.
Carpenter ants are most active at night. These ants are dormant during the winter, but workers may become active if the temperatures are mild and the nest receives sufficient warmth and sunlight.
Human Interaction and Urban Impact
Carpenter ants are economically important pests. They are among the top destructive pests in the U.S. They excavate and create galleries and tunnels in wood, which can weaken the wood and cause great damage. These areas have a noticeably well-sanded appearance and are free of sawdust and other debris. The extent of damage to wood structures varies. The more time a colony is present in a building, the greater the damage.
Carpenter ants do not have the ability to sting. Although they do not usually bite, they may if they are disturbed. If bitten, a slight burning sensation at the location of the bite may be felt. Redness, itching and mild swelling may accompany the bite. Any medical questions or concerns related to a carpenter ant bite should be directed towards a physician.
Prevention and Management Approaches
To prevent infestation of carpenter ants, tree stumps, logs and woodpiles should be kept away from buildings. Firewood should be stored away from the house on a concrete pad. Only enough firewood for one heating season should be stored. Woods that are moist, especially those with water damage, are at a heightened risk of carpenter ant infestation, so it is important to prevent moisture build-up in any part of the building. Trees and branches should be pruned so they do not touch the house or building; they can create bridges for carpenters to nest sites. Potential entryways into the building, such as gaps around doors and cracks in the foundation, should be sealed to prevent an infestation.
To manage the infestation of carpenter ants, nests in the building must be treated directly. Tracing the ants back to the nest can be a very difficult task. Treatment may require drilling into walls to allow for effective insecticide application. Heavily infested structural woods may need to be removed, and any moisture problems should be eliminated. In most cases of a carpenter ant problem, the control should be managed by an experienced pest control applicator, who has the experience and products necessary to control the infestation.
Other Online Resources
University of California-Davis
University of Nebraska-Lincoln
For information regarding labels of chemical control options, please visit NPIC MAPL
