Atta (genus) - Mounds

Mounds

An ant nest is used as a place to shelter the colony, for the queen to rear her brood, to store and cultivate fungi, and to exchange food among the workers. The location of the nest is crucial and is ideally situated for an optimal balance of protection and food abundance. Atta nests are below ground, can contain multiple chambers, and can be very complex. Usually, the size of the nest is a good indicator of how old the colony is, and the size of the nests differs among species. Atta cephalotes nests are about 30 m2, and A. vollenweideri has an average nest size of 34.6 m2. A. colombica has a much smaller verage size, which may be due to a small worker population and high nest relocation rate (R. Wirth, 2003). Amongst the Atta species, A. laevigata have nests that are the deepest and contain the most chambers (Lach, 2010). These nests can have between 1,100 and nearly 8,000 chambers, can be 7 meters deep, and foraging tunnels can extend as far as 70 meters (Moreira, 2004). The ants control the climate within underground chambers by building them at certain soil depths and near structures (e.g., rocks or mounds) that can collect heat. They can also add decaying plant material to the chambers to warm them. This is especially important in the brooding chambers, because the developing ants need to be kept at optimal temperatures for growth. Atta ants dispose of waste from the fungus garden and other parts of the nest into special waste chambers. Usually, older ants are responsible for this because they are generally less useful to the colony (Lach, 2010).