Army ants do not have a permanent nest but keep on the move, at best they stay in one place for a two to three weeks. Workers pack themselves around the queen and eggs/larvae making a structure that protects them. The youngest workers are on the inside and the elder ones on the outside.
The ants are on the move according to their breeding cycle – They get moving about 10 days after the queen lays her eggs. This wandering phase lasts about two weeks while the larvae develop. The ants move in the day capturing insects, spiders and even small vertebra’s to feed to the larvae.
At night they remain static until the next morning when the march starts again. Typically a large colony could consume up to five hundred thousand insects a day !
Our larvae spin pupa cases after about two weeks and they no longer need food. The colony is able to remain static for about 20 days during this phase.
Prey is now fed to the queen who lays the next batch of eggs, once the pupae emerge from the cocoons the eggs have hatched and the next batch of larvae need to be fed. The colony moves again.
About every three years virgin queens hatch and the colony splits two queens will survive with each having half the colony. Remaining queens are abandoned to die.
If the queen dies at some other time, the colony cannot create an emergency queen and the colony is likely to die too. It is however possible that the workers will fuse with another colony within a few days of their queen dying.
When army ants forage the trails formed can be 20 meters wide and up to 100 meters long. Ants move out along the outside of the trail and bring food back in the middle of the trail.
A colony of army ants foraging is called a swarm, swarm raid or column raid. This raid could be significant, up to twenty million ants.
The good news is that they don’t typically threaten humans or large animals but could be a problem if your house happens to be on their foraging path !