A Tropical Ant Temporarily Established in Iowa

Cosmopolitan tramp species of ants have been widely disseminated by man. About a dozen species have been introduced and are found in dwellings, greenhouses, nurseries and in and around urban communities in the southern and eastern parts of the United States. One of these, the Argentine ant, Iridomyrmex humilis Mayr, has become a serious pest in the southern states from Florida to California. It has also spread throughout the tropics and has in many areas replaced both native species and other earlier introduced species. Only one introduced species, the cosmopolitan Pharoah\u27s ant, Monomorium pharaonis (Linn), has been reported from Iowa (Buren, 1944), but this species is a house pest only, since it apparently does not live out-of-doors this far north. Two additional species have been reported from the Chicago area: the pavement ant, Tetramorium cespitum (Linn) and the Argentine ant, Iridomyrmex humilis Mayr (Gregg, 1944)