fusca-group field ants

The genus Formica has been divided by taxonomists into thirteen species groups based on distinctive features and behavior that can be easily seen in the field. The most diverse and most abundant of these is the fusca group. There are 45 species in the fusca group worldwide, 21 species in North America north of Mexico, and at least 8 species in Minnesota. These species were formerly in the subgenus Serviformica. That subgenus is not valid because it does not contain all of the descendants of one common ancestor and no others (monophyletic). It is not used in North America, where it is considered a junior synonym of Formica, but it is still used in Europe.

Most fusca-group field ants are found in grasslands and open woodlands. Some occur in closed canopy forests, in bogs, or in fens.

Fusca-group field ants are often the unwitting hosts of slave makers, including Amazon ants (Polyergus spp.) and slave-raider field ants (Formica sanguinea group), or of temporary social parasites in the rufa-group wood ants (Formica rufa group).

All fusca-group field ants have one or two offset teeth on the jaws (mandibles) at the base, the part closest to the head. Most are uniformly dark colored, black or dark brown. Some are reddish or yellowish on the front part of the body (mesosoma), sometimes also on the head around the mouthparts.

Sources

24, 27, 29, 30, 82.

Location: Woodbury, MN