Odorous House Ants are found throughout the U.S. and in spite of their name, are only an occasional pest in the house. Their name comes from the disagreeable odor similar to the smell of rotten coconuts, that is given off when the worker ants are crushed. Odorous house ants commonly nest outdoors in the soil under stones, logs, mulch, debris and other items. They will also nest indoors in wall and floor voids, particularly in moist or warm areas. If only a few workers (wingless ants) are observed in the house it is an indication that they are nesting outdoors and entering the house in search of food. If winged swarmers are found indoors, or if workers are consistently seen in great abundance, it likely indicates they are nesting within the house.

Odorous house ants regularly forage for food along well-traveled trails. They feed on dead insects, sweets and meats. One of their favorite foods is the sweet honeydew produced by plant sap feeding insects such as aphids and mealybugs.

Control of odorous house ants should begin with an attempt to locate the origin of the ants. Careful and frequent observation may be necessary to develop an opinion about the source. Ants entering from outdoors can be discouraged by sealing as many cracks and gaps in exterior walls as possible. An insecticide labeled for use outdoors in ant control can be used to control individual ant hills near the house or to create a protective barrier to stop foragers from wandering into the house.

The thief ant takes its name from their habit of nesting close to, and in some cases inside the nests of other ants, from which they steal food. Colonies of thief ants are generally small varying from a few hundred to several thousand workers and a multitude of queens. Swarmers take flight and mate from June until late fall. The developmental time from egg to adult takes around 50 days to several months.

Thief ant colonies are found both indoor and outdoors. Nests are large and often have tiny tunnels connecting to the nearby nests of larger ants from which they habitually steal food and brood. On occasions they have been known to takeover the associated ant nest. Outside they can be located under rocks, around walkways and house foundations, in rotting wood and exposed soil. Indoor nests are found in any small crevices, particularly woodwork and masonry, under floors and behind baseboards.

These ants are prevalent in households, in which they forage for foods with a high protein content such as grease, cheese, meat and hollow out seeds for the oil content. It is important to note that due to their small size, they can easily enter packaged foods. They also feed on immature forms of other ants and scavenge on dead insects and rodents. Unlike most other ants they do not appear to feed on sweets. They travel great distances in search of food, and once a source is located they form a trail from the food to the nest moving in columns of ants. The thief ant, however, is most renown for stealing from other nearby ant colonies.

In some areas of the country, carpenter ants (wood ants) cause more damage to structures than termites. They are difficult insects to control and can cause extensive damage to wood members in a fairly short period of time. Carpenter ants do not actually eat wood but excavate galleries within it to use as nesting sites. Foraging activity can occur at any time of day but usually peaks at night. When foraging inside houses, carpenter ants are attracted to sweets, meat, grease and fat.

A carpenter ant colony is usually formed by a queen who begins a nest in a piece of old buried wood or in a partially decayed tree or stump. In mature infestations, there may be as many as ten satellite colonies linked to the parent colony by trails. There is a frequent exchange of workers between these satellite colonies and the main nest. Colonies normally do not produce winged reproductive forms until they are at least three to six years old with emergence of swarmers typically occurring from May through July.

The most common way in which homes become infested is through emigration of an existing colony. Houses located near wooded areas or brush covered vacant lots are good candidates for infestation. Carpenter ant colonies are inclined to move if they are disturbed, as often happens during construction. Thus, new homes or those surrounding a new building lot present likely locations for attack.

The first sign of a carpenter ant infestation is usually the sighting of numerous workers throughout the home; occupants often complain of big black ants. However, the presence of workers alone is not conclusive evidence that a colony is established within a structure. Carpenter ant workers tend to roam far and wide looking for food, and some transient workers are sure to enter any home located in a wooded area. Signs of an active infestation include the presence of fibrous sawdust beneath slit-like openings in wood members and faint, rustling noises in walls and woodwork. A positive indication that an active, mature infestation is present is the emergence of large winged ants from walls, ceilings, or crawl spaces.