Solenopsis molesta, or the “thief ant,” is a common ant pest of homes throughout much of the US, but they are particularly abundant and troublesome in the southeastern states. As some insect enthusiasts may have already discovered by this species’ official name, thief ants belong to the same genus as fire ants. Unlike both invasive and native fire ant species in the US, thief ants are not known to bite or sting humans, and the excessively small size of workers, which is between 1.5 to 2 mm in length, make these ants less than intimidating when encountered. In fact, their small size makes thief ants difficult for entomologists and biologists to study. Although these yellowish to brown ants are small, they can become quite a nuisance due to their habit of nesting within a variety of indoor areas, and they are associated with the spread of disease-causing microorganisms within homes.
As if being nearly impossible to control and potential carriers of disease is not bad enough, thief ants may also be destructive to property, as they often establish nests within woodwork, sometimes resulting in damage. Thief ants frequently nest within trash, cracks and crevices in brick and cement foundations, kitchen cupboards, pantries, behind baseboards, attics, and within wall voids where they dispenser through homes by crawling on wiring and lumber structural components. Thief ants eat a variety of stored foods, particularly greasy and high-protein foods, like nuts, grains, fruits, animal fats, dairy and oils. Large numbers of workers have been found feeding on the remains of dead rodents that have collected in wall voids, and they may transmit pathogens from dead animals to food sources. Thief ants often invade homes in response to bouts of hot weather, and eradicating infestations is tremendously difficult. This is because multiple indoor and outdoor nesting sites may be associated with single infestations within homes, and detecting all nests takes time and patience.
Have you ever found ants gathering on grease stains and marks within your kitchen?