Formica (Field Ant) is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. Formica is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus Formica is the European red wood ant Formica rufa.

Habitat

As the name wood ant implies, many Formica species live in wooded areas where there exists no shortage of material with which they can thatch their mounds. One shade-tolerant species is F. lugubris. However, sunlight is important to most Formica species, and colonies rarely survive for any considerable period in deeply shaded, dense woodland. The majority of species, especially outside the rufa species group, are inhabitants of more open woodlands or treeless grassland or shrubland. In North America, at least, these habitats had a long history of frequent landscape-scale fires that kept them open before European settlement. Conversion to agriculture and fire suppression have reduced the abundance of most American Formica, while the cessation of traditional haycutting seems to have had the same effect in Europe. However, at least a few Formica species may be found in a wide range of habitats from cities to seasides to grasslands to swamps to forests of the temperate Northern Hemisphere.