Color: Pale yellowish to light or dark brown
Legs: 6
Shape: Unevenly rounded, thorax lacks spines
Size: 1.5 mm – 2.2 mm long – one of the smallest household ant species
Antennae: Yes
Region: Throughout most of the United States
Thief ants earned their name from their habit of nesting near other ant colonies, which they then raid for food and brood (larvae and pupae). While their colonies are generally smaller than those of other species, they can be highly prolific, containing multiple queens and several thousand workers. They are also commonly known as grease ants and are often confused with pharaoh ants due to their similar size and coloration.
Mating swarms (nuptial flights) begin in late July and end in early fall. Thief ants are attracted to greasy and high-protein foods such as nuts, breads, meats, fruits, animal fats, oils, and dairy products. When outside, they will also feed on almost anything organic, including insects, mealybugs, seeds, and germinating seeds.
Thief ants may carry disease-inducing organisms to human food, as they have been found feeding on dead rats and mice. They may also serve as intermediate hosts for the poultry tapeworm.
Inside, thief ants nest in small crevices, and woodwork and masonry. They commonly enter structures during hot weather in search of food and use the wires in wall voids to travel from room to room. Outside, they nest in exposed soil or under objects, in trash, rotten wood, and cavities in trees.
Nest location is critical for preventing thief ants; however, they are often difficult to locate. The best way to prevent a thief ant infestation is to work with a licensed pest professional who can implement a preventative pest management plan.
Their tiny size allows them to nest in hidden, hard-to-reach areas, making DIY treatments largely ineffective. In contrast, pest control experts, like RK Environmental, use baiting strategies and specialized treatments to eliminate the entire colony, not just the ants you see.
Yes, thief ants can have wings. Reproductive males and females, known as swarmers, develop wings during mating season, typically in late summer. After mating, the males die, and the fertilized queens shed their wings to establish new colonies.