Although there are twenty five species of ants in the United States that are known to infest homes, carpenter ants, odorous house ants, and pavement ants are three of the most cited as structural and nuisance pest ants according to Dr. Laurel D. Hansen of Spokane Falls Community College and Washington State University.
Carpenter ants are relatively large ants that range in size from one-quarter of an inch for a worker ant to up to three-quarters of an inch for a queen. They are usually red, black, or a combination of the two colors. Although they are found throughout the United States, they are most prevalent in the North. The carpenter ant gets its name from the way it hollows out wood in order to build a nest. Their excavation results in smooth tunnels inside the wood. Carpenter ants usually attack wood that is or has been wet and damaged by mold but they commonly begin building paths through dry, undamaged wood after they have tunneled through the damaged wood.
Odorous house ants range in size from one-sixteenth of an inch to one-eighth of an inch long. They are brown or black in color and are found throughout the United States. The odorous house ant gets its name from the strong odor it gives off when it is crushed; the smell is similar to a rotten coconut. Odorous house ants nest near moisture sources in homes, such as in heaters, beneath leaky fixtures in wall voids near hot water pipes, and inside wood damaged by termites. They are constantly in search of food and are particularly attracted to sweet smelling foods.
Pavement ants are another species of ants that are a great nuisance in the United States. These dark brown to black ants are approximately one eighth of an inch long and are found throughout the country. Pavement ants get their name because they make nests in or under cracks in pavement. Pavement ants are omnivores that have been known to eat almost anything. They devour seeds, nuts, fruits, meat, bread, and cheese. They will explore areas up to thirty feet from their nests and are known to climb walls to enter homes.