By Alex Wild [CC0], via Wikimedia Commons
Thief ants are a native species that is found throughout much of the eastern 2/3 of the United States. These ants are so small that they frequently go unnoticed in the home and would certainly enjoy feeding on potato chips and other 'greasy' items in the kitchen. They get their common name from the habit of nesting close to other ant species and raiding those nests of eggs, larvae and other food items.
Description and Behavior
Workers are 1/16 inch (1.5 mm) long and monomorphic (all members are about the same size). They are yellowish or tan in color and are usually lighter than other tiny ants (except for Pharaoh ants). Thief ant eyes are very tiny containing only 4 to 6 ommatidia (facets). The 10-segmented antenna has a pronounced 2-segmented club. The pedicel has 2 nodes and the thorax has an uneven profile. Stinger is very small. This ant and the Pharaoh ant are often misidentified because of their similar size and color.
Thief ant, Solenopsis molesta (Marion R. Smith, USDA)
Solenopsis molesta colonies may have up to several thousand workers and multiple queens. They tend to nest in or close to the nests of other ants and will steal food and larvae (as food). There is a strong preference for protein, as thief ants will feed on animal carcasses, but they are also attracted to sweets.
Thief ants will enter structures through cracks in the foundation or small openings in woodwork and commonly during hot weather. They forage in trails throughout a structure seeking protein, sweets and liquid. Outdoors they nest under objects and in soil.
Control of thief ant ant workers can be accomplished through the use of baits. The workers carry the baited material back to the nest, eliminating the colony. Many different types of bait are available to the homeowner in this regard. However, baits containing hydramethylnon, fipronil or boric acid are slower acting and do not kill the workers before they have had a chance to share the baits with the queen and developing immature ants. Purchase baits that are specifically for protein/fat loving ants. Place the baits in areas where ant activity has been observed and make certain that children or pets cannot reach them. Maintain sufficient amount of baits to satisfy the colony by replacing used baits. It may require two weeks or longer to obtain control.
Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.
Authored by: Steve Jacobs, Sr. Extension Associate