Thief Ant

Size

Thief ant workers are about 1/16 in (1.3-1.8 mm) long; queens are about 1/4 in (6-7 mm).

Color

Body is pale yellow to light or dark brown.

Where

This is a native species and is found throughout most of the U.S.

Habitat

Thief ant nest inside in small crevices, and in woodwork and masonry using wires in the wall voids to travel from room to room. They commonly enter structures during hot weather. Outdoors, Thief Ants nest in exposed soil or under objects, in trash rotten wood, and cavities in trees.

Diet

Thief ants feed on almost anything organic including insects, honeydew (tend plantlice, mealybugs and scales insects), seeds and germinating seeds. Thief ants have been also found feeding on dead rats and mice and, therefore, they may carry disease-including organisms to human food. They also may serve as intermediate hosts for poultry tapeworm, Raillientina tetragona (Molin).

Biology

Colonies are composed of a few hundred to several thousand workers and many queens. Developmental time is 50 days to several months. Flights of swarmers begin in June and end in late fall. A single inseminated female can establish a new colony, but some may return to their nest after mating.

Damage

Thief ants have been also found feeding on dead rats and mice and, therefore, they may carry disease-including organisms to human food. They also may serve as intermediate hosts for poultry tapeworm, Raillientina tetragona (Molin).

Detection

Location of the nest(s) is crucial and can often be accomplished by following the trail of foraging workers back from a food source.

Control

1. Using a boric acid dust in the voids of outside ground floor walls along with a perimeter treatment of nonrepellent pesticide is effective.

2. Be thorough and include treatment up under the siding to foundation wall junction if such is present.

3. Seal all electrical and utility line entrances.

4.Trim back all vegetation that is contact with the structure.

5. On the inside, a light application (misting or spritzing) of a non-repellent pesticide directly onto the foraging trails of ants is very effective.

6. Learn about the biology of Thief ants, and use good strategy! Use only pesticides registered for this species, read entire label before use, and carefully observe all label directions, restrictions and precautions.