A queen (right) and two worker Stenamma dyscheres. Notice the small eye size of the workers, a trait common to all subterranean ants. Empire Mine State Park, California, USA
Most "acorn ant" species are less choosy about nesting site than their name suggests. This colony set itself up in a narrow crevice between two flat stones. Visible here are all components of a mature ant colony: queens, workers, a single male, and brood in varying stages of development. South Bristol, New York, USA.
Queen ants are the fertile females in the nest specialized for reproduction. In some ant species, such as the little fire ant Wasmannia auropunctata, queens are much larger than the sterile workers. Gamboa, Panama