Grease ants get their name from their attraction to foods containing fats and oils. They are also known as thief ants because they make their nest close to the nests of other ants and steal their food.
Grease ants are tiny ants. The workers are about 1/16″ long. They are usually yellowish, but they can be tan or brown. Because of their size and color, grease ants are often confused with pharaoh ants. There is a difference in the “club” at the end of their antennae: the grease ant has a 2 – segmented club and a pharaoh ant has a 3 – segmented club. Pharaoh ants usually have a dark mark at the back of their abdomen. This is easier to see than the segments of the antenna. A magnifying glass can help.
Outdoors, grease ants feed on insects. They also tend plant-feeding insects and eat the honeydew that they produce. They nest in cavities in trees and inside rotting logs. They seem to enter homes during hot weather.
Grease ants often enter homes by walking on the limbs of bushes that touch the house. They walk in through cracks around windows or doors. Because they are so small, grease ants can nest in cracks and crevices. They often nest inside of walls.
Indoors, these ants seem to prefer to feed on foods that are high in protein such as meat, dairy products, and peanut butter. However, they will also feed on sweets.
Grease ant workers move around in lines. They follow edges, like baseboards when they look for food. Sometimes they travel from room to room by following electric wires inside of walls. By following the trails of workers, it is often possible to locate the grease ant nest.