Prenolepis imparis is an ant species that is abundant throughout the United States where they are common pests of homes. This species is more commonly known as the “winter ant,” or the “small (false) honey ant,” and they are unique for being cold-hardy insects that are most active when temperatures are between 40 and 60 degrees. In fact, workers from this species have been found foraging outdoors in freezing temperatures and they are commonly spotted crawling on snow. Unlike all other ant pest species, winter ants are active year round in northern states, but they are only active during the winter and spring seasons in most southern states. Winter ant workers often enter homes from outdoor nests to seek out food sources, but workers are also able to establish indoor nests.

Winter ant workers have smooth and shiny bodies that are dark brown in color, and they are between 2 and 4 mm in length. Workers usually invade homes from outdoor nests where they seek out and consume a variety of human foods, including sugar, syrup, honey, cake, bread, fruit and meat. Workers occasionally nest within homes where large food sources can be easily accessed, and it is not uncommon for workers to infest, and therefore, contaminate stored foods within kitchen cupboards and pantries. During the winter when soil is frozen, winter ants nest above ground, and during the summer they usually nest within soil.  Workers that forage indoors often originate from nests located in soil between slab expansion joints. Entire winter ant colonies have been collected from potted plants within homes, and infestations are often noticed when residents find that their plants have sustained damage caused by workers extracting honeydew. In order to eliminate winter ant infestations, all of their nests must be located and the inhabitants destroyed. Outdoor nests are treated with residual insecticide sprays, and indoor nests are usually located within wall voids and other concealed areas where minimal amounts of residual insecticide dusts can be injected. Sweet baits are also useful for ridding homes of winter ant infestations.

Have you ever found ants foraging during the winter season?