Nomadic behaviours and reproduction
As discussed in the previous page, some species of army ants lead a completely epigaeic existence, making temporary bivouacs made completely out of the ants themselves. The ants have 2 phases during their life, the nomadic stage and the statary phase. The nomadic phase is, as the name suggests when the colony is nomadic (Gotwald, 1995). It starts with the callow workers emerging from their cocoons . The nomadic phase is characterized by daily raids that begins in the morning and lasts til dusk. At which point the colony congregates and forms a new bivouac. During the nomadic phase the queen doesn't lay eggs and the new larvae begin to spin their cocoons. This is the most active phase and it lasts between 11and 20 days, depending on the species.
The second phase of the cycle is the statary phase. This phase involves a significant reduction in colony activity. Raids are still conducted however they are smaller and not as strong. During this phase, the queen's gatser, in which she stores her eggs, swells considerably. The bivouac is made in a sheltered area to provide extra protection for the queen and the eggs during this phase (Gotwald, 1995). The statary phase ends when the pupae from the previous brood emerges from their cocoons as workers (Brady, 2002). This phase lasts between 18 to 21 days.
Army ants reproduce by colony fission. This means that suitable fertile queens gather a significant following from their current colony and leave to form a new colony. This nomadic behavuiour has enabled the ants to be able to develop significant numbers of successful colonies in their environments (Berghoff, 2003)