Army Ant

• GeneralIt builds no anthill: the workers link their bodies into a living nest called a bivouac.
• comportamientoIt builds no permanent nest: its colonies are nomadic, and the workers link their own bodies into temporary structures (a bivouac) to shelter the queen and the larvae.
• Its hunting swarm advances in a fan across the forest floor, up to twenty metres wide, and takes every arthropod and small vertebrate that fails to escape.
• Dozens of bird species, the so-called ant-followers, make a living by accompanying these columns and catching the insects fleeing the swarm, and some depend on them entirely.
• The workers bridge gaps in the ground with their own bodies and adjust the shape of the bridge to minimise the number of ants tied up in it.
• It is the only Eciton species that hunts in swarms: a fan-shaped front more than fifteen metres wide, instead of the narrow columns of the rest.
• It builds no nest: hundreds of thousands of workers link together to form a living bivouac, among buttress roots or up to twenty metres above the ground in the trees.
• It alternates phases: some twenty nomadic days, during which it shifts bivouac almost every night, and a statary phase in which the queen lays between 100,000 and 300,000 eggs.
• It is a keystone species of the tropical forest: more than three hundred species depend on its columns, among them the antbirds, which hunt the arthropods fleeing the swarm.
• The workers are polymorphic, from 3 to 12 mm, with a soldier caste bearing long sickle-shaped mandibles.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

The floor of tropical rainforest

Sexual maturity

The new queens are ergatoid (wingless) and mate within the colony itself with several males before fission; the male is carried into the nest by the workers, copulates once and dies within 48 hours. The queen stores the sperm to fertilise all her future laying

Gestation / incubation

The cycle alternates two phases tied to the development of the brood: a nomadic phase while the brood is in the larval stage, with intense raiding and emigration at the end of each day, and a statary phase as soon as the larvae pupate, when the emigrations cease and the colony stays put

Litter / clutch size

The queen lays up to 100,000 eggs every three weeks all year round; the colony holds from hundreds of thousands to two million individuals and splits in two about every three years, when it produces thousands of males and a few new queens

Sources consulted: https://en.wikipedia.org/wiki/Eciton_burchellii; Britannica, ficha Eciton army ant; ficha de especie de Eciton burchellii (UWI); AntScout; AntWiki, Eciton burchellii (Schneirla); Animal Diversity Web, Eciton burchellii; AntWiki; Ficha de especie de Eciton burchellii (UWI, Holldobler & Wilson 1990); Britannica; Animal Diversity Web

Best time: Active all year in lowland rainforest, from Mexico to Argentina; the raids are by day and form carpet-like fronts up to 25 m wide. It builds no nest: the colony forms a bivouac out of its own bodies, hooked together by the tarsal claws, under fallen trunks or up to 20 m high in the trees