Odorous House Ants

Get Rid of Odorous House Ants in Your Home or Business

General Information

Found in each of the lower 48 United States, the odorous house ant frequently invades homes in the New England area. The odorous house ant, Tapinoma sessile, gets its common name from the unpleasant odor it creates when crushed. The acidic smell, often compared to that of a rotting coconut, is produced by the anal glands of the species.

Odorous house ants can create shallow nests almost anywhere near a viable food supply. Odorous house ants regularly move nests or split up into groups to form new colonies.

Though nests may have thousands of members, odorous house ants typically break off from mother colonies before nests become too large. Multiple reproductive queens in each colony give the odorous house ant the tendency to “appear overnight.”

Picture of Odorous House Ants

Appearance & Identification

What Do Odorous House Ants Look Like?
Odorous house ants are dark brown or black in color and are less than 3 millimeters or 1/8 inches in length. Contrary to other ants, the odorous house ant does not have a visible node on its petiole (waist). There is one node present but it is covered by the abdomen.

During mating seasons, the ant produces winged reproductives that look nearly identical to workers except for a large front pair and smaller rear pair of wings. A larger abdominal section distinguishes queen ants from workers.


Always on the move, odorous house ants relocate their nest every three to four weeks on average, depending on weather conditions and available food sources. Locations near water serve as preferable nesting sites for the pest.

The ants may seek shelter indoors during heavy rains to avoid flooding or during droughts to find water. Interior nests are often around leaky faucets, pipes, or heaters. The odorous house ant may also find shelter under dishwashers, damaged insulation, or in wood vacated by termites. Popular outdoor habitats include under stacked firewood or rocks, in open soil, or any other location near food.

When foraging, an odorous house ant may travel more than 25 feet from its nest to find food or water. The creatures leave scented foraging trails for other colony members to follow and are often seen marching in straight lines to and from food sources.


What Do Odorous House Ants Eat?
Odorous house ants love to eat honeydew, a substance secreted by insects like aphids, leafhoppers, mealybugs, and scales. The odorous house ant will go as far as to protect honeydew-producing insects from predators to secure its favorite food source. Additional diet choices include nectar from flowers, decomposing animals, and other insects, dead or living.

When it comes to human fare, the sweet-toothed insects prefer to feast on sugary substances but will consume many other foodstuffs, as well. Though the pest can find shelter in vacated termite colonies/galleries, the odorous house ant does not consume wood and therefore does not pose a threat to the structural integrity of homes.


Odorous house ant colonies are polygamous, or have several queens, giving the species a higher rate of reproduction than other types of ants. Reproduction generally takes place in the summer months of June and July, with winged reproductive/swarmers emerging as early as May in some cases. In the spring, colonies produce male and female swarmers, which leave the colony to mate upon maturation.

The males die shortly after mating, and the females begin laying eggs. Most egg-laying takes place between April and November; however, odorous ants that colonize indoors take advantage of the consistent temperatures and moisture sources and often lay eggs year-round. As colonies grow, reproductives lay at least one to two eggs a day, and the workers tend to the young as they mature.

An additional reproductive tactic includes budding, where the ants form satellite nests near the mother colony. Relocating or beginning new nests does not hinder the reproductive process, and the workers move the brood from one location to the next when necessary.

Problems Caused by Odorous House Ants

Odorous house ants do not sting as some ants do, and though the pest has the ability to bite, it does not cause much pain. Its propensity to consume a wide variety of substances increases its likelihood of contaminating food during home infestations. Contaminated food should be thrown out immediately to avoid risk of food poisoning.

Homeowners should try to find nests immediately after finding a foraging worker odorous house ant indoors. Prolonging extermination complicates infestations, as odorous house ants frequently spawn satellite nests near new food sources. Eliminating the pest before it creates multiple nests proves advisable and reduces the overall frequency of ant sightings around the house.

Signs of Infestation

Odorous house ants often leave visible trails where the most traffic occurs, which can aid in locating the origin of the pest. When indoor infestation occurs, winged reproductives are sometimes seen flying around light fixtures or windows during mating seasons. The sighting of winged ants typically indicates the nearness of a mature nest, as many colonies reach several thousand members before producing reproductive swarmers.

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To prevent outdoor infestation, homeowners should avoid leaving large amounts of leaf litter in the yard and keep wood piles away from the house. Additional tactics include reducing branches or vines that come into contact with the house and sealing up potential entry points as much as possible.

Indoor prevention involves cleaning up well after meals by sealing up leftovers, washing dishes, and wiping counters. Sweeping and mopping floors regularly to eliminate crumbs and sticky residue from spills is also helpful.

Insecticidal baits designed to attract ants with a preference for sweeter foods are available. Ants take the slow-killing insecticides found in the bait back to the nest, which exposes the rest of the members.

However, commercially available baits and insecticides do not always eliminate the pests and may pose health threats to children or pets. When faced with an infestation, contact a pest control expert who possesses the tools and know-how to fully exterminate odorous house ants.