Thief Ants (Solenopsis molesta)
by Jody Green, Extension Educator
Ants are the most common and obvious kitchen invader and many come in from outdoors in search of food, warmth and moisture. One ant often goes unnoticed because of their tiny size. They are called thief ants because they are known to nest close to other ant species, steal eggs, larvae and food in order to feed their own colony.
Thief ant workers are among the smallest species of household ant. All are tiny, approximately 1/16-inch long and a pale golden yellowish-brown color. All workers are the same size and colonies contain multiple egg-laying queens. They are known as “grease” ants because of their preference for oily, greasy food resources rather than sugary. Occasionally, they are mistaken for Pharaoh ants, which look similar but can be differentiated based on their antennae and their affinity for sweets.
Thief ants nest outdoors under objects on the ground such as logs and stones, around foundations and in bare soil. They enter a structure through small cracks in the foundation and can nest in cracks and crevices indoors behind baseboards, under floors, wall voids, cupboards and other small compartments. Food sources include meats, vegetable oil, dairy products, nuts, seeds and animal fats. Due to their small size, they can invade packaged food and seemingly sealed containers.
Sanitation is very important when it comes to ant prevention. Cleaning up spills, wiping food containers, washing dishes, mopping floors, proper food storage (including pet food) and reducing the time food sits out are ways to avoid attracting ants into the kitchen.
Insecticidal treatment for thief ants involves baiting. Baiting involves strategically applying an attractive, palatable, slow acting toxicant that utilizes the organism’s behavior and biology. There are many effective baits on the market today with a variety of active ingredients including the active ingredients: hydramethylnon, fipronil or boric acid. The most attractive baits will be one with grease or oil inert ingredients.
Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Nebraska–Lincoln is implied. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office