is a genus of New World army ants (subfamily Ecitoninae) containing about about a dozen species, including Eciton burchellii
(common name army ant), considered to be the “archetypal”, and one of the best studied, army ant. Eciton
species are found in different habitats from Mexico through Argentina. While some species, notably E. burchellii
and E. hamatum
have enormous colonies, sometimes containing more than a million individuals, and are active in enormous raiding swarms out in the open during the day, other species forage and carry out raids and other behaviors only at night or under cover and thus less is know of the behavior and diets of these other species. E. burchellii
and E. hamatum
are generalists, eating just about anything they can catch or find. Like Old World army ants Eciton
ants do not construct permanent nests, rather the individuals in a colony periodically come together in a giant ant mass (called a bivouac) in the middle of which the queen lays her eggs. Eciton
ants alternate between a more stationary period, where they return to their temporary bivouac every night and an active, nomadic phase where the ants swarm and move the colony regularly.
New World army ants were historically thought to have evolved independently (convergently) from the Old World army ant lineage, but new molecular evidence indicates that they share a common ancestor in the times of Gondwanaland (100 million years ago).
(Brady 2003; Snelling and Snelling 2002
; Wikipedia 2011a
; Wikipedia 2011b