Army Ant

The name army ant (or legionary ant or "Marabunta") is applied to over 200 ant species, in different lineages, due to their aggressive predatory foraging groups, known as "raids", in which huge numbers of ants forage simultaneously over a certain area, en masse.

Another shared feature is that, unlike most ant species, army ants do not construct permanent nests; an army ant colony moves almost incessantly over the time it exists. All species are members of the true ant family, Formicidae, but there are several groups that have independently evolved the same basic behavioral and ecological syndrome. This syndrome is often referred to as "legionary behavior", and is an example of convergent evolution.

Most New World army ants belong to the subfamily Ecitoninae which contains the two groups, the Cheliomyrmecini and Ecitonini. The former contains only the genus Cheliomyrmex whereas the latter Ecitonini contains four genera, Neivamyrmex, Nomamyrmex, Labidus, and Eciton. The largest genus is Neivamyrmex which contains more than 120 species. But the most predominant species is Eciton burchellii of the genus Eciton; its common name "army ant" is considered to be the archetype of the species. Old World army ants are divided between Aenictini and Dorylini. The Aenictini contains more than 50 species of army ant in the single genus, Aenictus. However the Dorylini contains the Dorylus, these are the most aggressive species of driver ants, there are 60 species known.

Originally the Old World and New World lineages of Army Ant were thought to have evolved independently, an example of convergent evolution. However in 2003, genetic analysis of various species suggest that they all evolved from a single common ancestor which lived approximately 100 million years ago at the time of the separation of the continents of Africa and America. Army ant taxonomy remains ever-changing, and genetic analysis will continue to provide more information about the relatedness of the various species.