Tetramorium tsushimae, a new invasive ant in North America

Combining molecular and morphological evidence, an invasive ant in Missouri and Illinois, USA, is identified as Tetramorium tsushimae Emery, 1925, a polygynous-polycalic species native to East Asia. T. tsushimae is recorded as invasive for the first time. RFLP and worker morphometrics provide tools for reliable determination. Mitochondrial DNA data reveal the probable geographic origin of the invasive populations to be Japan.