Formica gynocrates, a recently described species of slave-making ant, was found at the E. S. George Reserve in southern Michigan. It contrasted with the other five sanguinea group species found there by living in dry fields and enslaving a field-dwelling ant, Formica vinculans. Slave raids were carried on from 16 June to 11 September and flights occurred between 5 July and 14 August. Three other sanguinea group species, F. subintegra, F pergandei, and F. rubicunda, were most common along field-wood ecotones. They enslaved F subsericea, and F pergandei occasionally took F pallidefulva nitidiventris F subnuda lived in and under logs and usually had no slaves or a limited number of F subsericea. F. creightoni was rare, lived in woods, and enslaved F. lleogagates and F lasioides. Raids of subintegra, pergandei, and rubicunda took place from late June to September, and flights occurred from the first or second week of July until early August.
"The Slave-making Ant Formica Gynocrates (Hymenoptera: Formicidae),"
The Great Lakes Entomologist, vol 18
Available at: https://scholar.valpo.edu/tgle/vol18/iss3/6