Odorous Ants

Facts, Identification & Control

Latin Name:

Tapinoma sessile


Odorous house ants, sometimes called odorous ants, are small, measuring 2.4 to 3.3 mm in length. They have dark brown or black bodies with one node on their petiole, which is hidden by their abdomens. Odorous house ants have an unevenly shaped thorax when viewed from the side. The most distinguishable characteristic of odorous house ants is the smell of rotten coconut that is emitted when their bodies are crushed.

Behavior, Diet & Habits

Odorous ant nests are found in a great variety of situations. Inside buildings, they are often found nesting in the walls or beneath the floor. They are most likely to invade buildings during rainy weather. Odorous ants travel in trails, foraging day and night.

Outdoors, odorous ants often feed on honeydew, a sugary waste produced from sap from feeding insects such as aphids. Inside buildings, they prefer sweet items but will also feed on meats and grease.


New colonies are created in two possible ways. The first is when the colony produces winged male and female reproductives who swarm out of the nest, mate and the fertilized female establishes the new colony. Swarming typically occurs in the summer months. The second way odorous ants form new colonies is when a queen and workers bud off from the main colony and form their own new colony.

Odorous ants develop by complete metamorphosis from egg, larva and pupa to adult. Development time from egg to adult is affected by several variables, such as temperature, but typically ranges from 34 to 83 days.

Because odorous house ants tend to forage inside homes, they can easily contaminate human food supplies. While odorous house ants do not sting or bite, they can become persistent pests, traveling indoors in large numbers.

Signs of an Odorous Ant Infestation

The most likely sign of odorous house ants is the foraging worker ants, although winged swarmers also might be observed.

More Information

Odorous house ants are opportunists, nesting both indoors and outdoors. Indoors, odorous ants can nest in wall crevices, near heaters, water pipes, under carpets, beneath floors or sometimes behind paneling. Outdoors, odorous house ants place their shallow nests beneath soil as well as in logs, mulch, debris and under rocks.

Like all ants, odorous house ants live in colonies. Each colony may contain two or more queens and over 100,000 workers. The queens of an odorous ant colony can produce thousands of workers and hundreds of reproductives.

Odorous house ants forage for food night and day. Outdoors they prefer honeydew from aphids and mealybugs. When the honeydew supply is reduced in autumn, they may move indoors for food. Indoors, they eat meats, sugary foods, dairy products, pastries, cooked or raw vegetables and fruit juices.

When alarmed by a predator, worker odorous ants will move in quick, erratic motions, raising their abdomens into the air.