Dorylinae

Members of this subfamily are known as army ants and are sometimes referred to as legionary ants in the New World and driver ants in the Old World. They are predaceous and are known for their foraging expeditions the size of which are sometimes exaggerated. Army ants exhibit a number of morphological and biological pecularities not common to most ants such as wasplike males, wingless termitelike females, blind workers, and their raiding and emigrating behavior. Rettenmeyer (1963) outlined the following traits in which they differ from other ants: (1) They feed almost exclusively on animal prey which is collected by large groups of raiding workers; (2) their raiding columns usually connect to the nest by at least one continuous column; (3) the entire colony periodically and frequently emigrates to new nest sites; (4) emigrations are largely dependent on the size, caste, age, and range of ages of the brood (or broods); and (5) the colonies are founded by division of an entire colony into two (or possibly several) daughter colonies. Other ants may possess some of these traits, but not all of them. ~Much of the biological work on army ants has been done in Central America on the terrestrial species of Eciton which bivouac in large clusters above the ground and whose colonies may number up to a million individuals. Most of the army ants, however, are subterranean in habit, though the raiding columns of some may appear above ground. Raiding may be in columns only several ants wide or in swarms of a fan-shaped pattern. Most of the prey is other Arthropods, only occasionally vertebrates. All species have nomadic and statary activity cycles where the entire colony moves from one area to another, a unique behavior studied by Schneirla and Rettenmeyer in the papers listed below. ~Borgmeier's revision of 1955 is the most definitive taxonomic work on this subfamily for the New World. He recognized 137 species in 5 genera and 2 tribes. Only the tribe Ecitonini is found in the United States; the other tribe, Cheliomyrmicini, includes a single genus of several species found from Mexico to Brazil. In the United States, most species are found in the Southwest, though several reach the Atlantic coast and range north to Iowa, Ohio, and Virginia. Most of the taxonomy is based on males and workers, and for some species only one caste is known. Further study and association of castes may result in some synonymy, especially in Neivamyrmex.