The army ants of the Old World, are mostly made up of members of the genus Dorylus; some of the most fascinating ants in the world. Their famous swarms have given them nicknames like “driver ants” or “safari ants.” Dorylus species range in color from rust to black, and are found from Africa extending eastwards into South East Asia.
Army ants can be grouped into 2 types; those that forage on the surface of the ground, and those that forage underground. The surface foragers are the ones that can develop into massive colonies, eating almost anything in their path that moves. But the majority of army ant species’ are actually subterranean foragers, and consequently, little studied.
There are a few Dorylus species in South East Asia (out of the 140 known species/subspecies), but not much is known about them (like termites). Among the most well known ones due to this excellent study, is Dorylus laevigatus. They are subterranean Asian army ants.
I encountered a colony of Dorylus laevigatus the other day, and what struck me was they did not seem aggressive when uncovered. It could be due to the colony being in “resting mode,” as army ants always have periods during which they construct temporary nests in between their migrations. Dorylus laevigatus tunnels extensively, feeding on small soil invertebrates, termites included.
The ants themselves are rather small, being a little over 1 cm in length for the major worker (or “soldier”). Dorylus are strongly polymorphic, as in having many sizes, for its workers. The smallest worker size is less than a third of the size of the major worker and is a lighter yellow color compared to the major.