Paratrechina longicornis, or the Longhorn Crazy Ant, as the species is more commonly known, is one of the most commonly encountered ant pests within Arizona homes. This ant species is native to Africa, but they have established an invasive habitat in the southern and eastern US states where they frequently invade homes in massive numbers in order to locate food sources. The longhorn crazy ant is often confused with another invasive ant species in the US known as the Tawny crazy ant (Nylanderia fulva). Much like Tawny crazy ants, longhorn crazy ants are relatively small in body size and workers are notable for their erratic movements and for their habit of invading homes in large numbers. Longhorn crazy ants often invade homes after traveling long distances from their nesting site, which makes eliminating infestations rather difficult.
Longhorn crazy ant workers that forage within and around homes can be recognized for their ⅛ inch long bodies, and for their fast and erratic movements. Workers have long legs and antennae and their bodies are greyish-black and covered in many long hairs. Longhorn crazy ants are more prevalent in urban and suburban areas than they are in rural areas, indicating that they prefer to dwell in close association with humans. Colonies contain as many as 2,000 workers and around 40 queens, and workers are capable of nesting indoors, but in the hot southwest they typically invade homes from outdoor nests. Outdoor nests are often located in close proximity to homes within soil, but workers are known to invade homes that are located more than 50 meters from nests. Since longhorn crazy ants live in colonies containing many queens, new colonies are likely started by queens that leave existing colonies. Given their erratic movements, it may seem like workers don’t follow fixed foraging trails while traveling between homes and nests, but researchers claim that they do, and patiently following workers will eventually reveal the location of their nests. When nests are located, they must be destroyed to end infestations, and in some infestation cases, perimeter insecticide treatments around homes is necessary to prevent further invasions.
Have you ever found erratically-moving ants in your home?