These are among the largest ants from 1/8" to 1/2" long, but can vary greatly in size and queens are larger. The most common species is black, but some are red and black or red and brown. Their colonies are of moderate size and can contain over 3,000 to 100,000 workers and usually only one functional, wingless queen is in a single colony. Workers have large mandibles which are used for cutting wood. They reside both outdoors and indoors in moist, decaying or hollow wood. They cut "galleries" into the wood grain to provide passageways for movement from section to section of the nest. They can leave "sawdust" behind that provides clues to nesting location. They are very difficult to control.
Larger Yellow Ant
Larger Yellow Ants are about 1/4" long and are yellow-orange in color. One key identifying trait is if the ant is crushed it will smell like citronella or have a "lemon-like" smell. These ants nest in the soil. They will construct their nests in the soil under logs, patio blocks, porches, rocks, concrete patios, etc. They can also be found in open areas of soil. They have been known to excavate large amounts of soil when building a nest. If they are under a concrete slab (patios for example) the soil may continue to pile up. They can become a nuisance indoors when they try to enter through cracks or gaps in the foundation of homes, however they do not enter in search of food. They feed almost exclusively on honeydew and there is no record of them feeding on household foods. Locating the source of the nest and treating it directly is the best way to control this ant.
Odorous House Ant
Odorous Ants are 1/16" to 1/8" long. They are brown to black. Colonies of this ant can be several hundred to 100,000 ants. There are usually many queens in a colony. Inside, these ants usually construct their nests in wall voids especially around hot water pipes and heaters, in crevices around sinks, cupboards, etc. These ants prefer sweets but also eat foods with high protein content and grease such as meats and cheese. Outside they are often found in exposed soil, but mostly under objects.
Pavement Ants are 1/16" to 1/8" long. They are light brown to black. The colonies of this ant can be very large, up to about 4,000 ants and several queens. These ants can be found inside structures in such places as inside walls, insulation, and under floors. They often follow pipes which come through slabs or access to upper floors of buildings. Outside these ants nest under stones, in cracks in pavement, and next to buildings. Although not aggressive, workers can bite and sting. These ants feed on almost anything including insects, honeydew, seeds, plant sap, and household foods such as meats, nuts, cheeses, honey, and bread.
Pharaoh Ants are about 1/16" long. They are usually pale in color, varying from yellowish to reddish. Their colonies are very large ranging from several thousand to several hundred-thousand, and can have several hundred reproductive females. These ants rely on artificial heating in buildings to survive. Infestations commonly occur in food service areas. They will nest in any well protected and hidden areas throughout a structure. They can also nest outdoors in lawns and gardens. A colony of Pharaoh Ants will scatter if a toxic substance disturbs it.