Acromyrmex versicolor desert leafcutter ant nest in an urban setting. Green Valley, Arizona, USA

The chaco leafcutter ant Atta vollenweideri forms the largest colonies of any social animal on earth. Mature nests such as the mound pictured here may contain several million ants. Note the cleared foraging trail leading away from the nest in the foreground. Resistencia, Chaco, Argentina

The chaco leafcutter ant Atta vollenweideri forms the largest colonies of any social animal on earth. Mature nests such as the mound pictured here may contain several million ants. Resistencia, Chaco, Argentina

The busy nest entrance of Atta colombica, a forest-dwelling leafcutter ant. Gamboa, Panama

Ventillation tunnels on a mound of the chaco leafcutter ant Atta vollenweideri. Resistencia, Chaco, Argentina

The carton nest of an Azteca trigona -complex species hangs from a tree branch. Gamboa, Panama

The hollow stem of a Cecropia ant-plant is divided into chambers to house fierce Azteca alfari ants. Inside, the ants raise their brood and tend to mealybugs. Gamboa, Panama

Azteca constructor

Splitting open the hollow trunk of a Cecropia tree reveals carton galleries constructed by symbiotic Azteca ants. These galleries are empty, as the colony has moved upwards towards the tips of the branches. Armenia, Cayo District, Belize.

Azteca constructor

Splitting open the hollow trunk of a Cecropia tree reveals carton galleries constructed by symbiotic Azteca ants. These galleries are empty, as the colony has moved upwards towards the tips of the branches. Armenia, Cayo District, Belize.

Overdispersed nest mounds of Camponotus termitarius, an emerging pest of pastures and old agricultural fields in northern Argentina. Perdices, Entre Rios, Argentina

A distinctive thatch mound of Camponotus rufipes. Viçosa, Minas Gerais, Brazil

A distinctive thatch mound of Camponotus rufipes. Viçosa, Minas Gerais, Brazil

A colony of Cephalotes rohweri inhabits the abandoned burrow of a wood-boring beetle in a Palo Verde tree. Tucson, Arizona, USA

A basketball-sized carton nest of Crematogaster castanea tricolor in an Acacia tree. St. Lucia, KZN, South Africa

An arboreal carton nest of Crematogaster castanea tricolor. This nest is about the size of a softball. St. Lucia, KZN, South Africa

A nest of Dorymyrmex insanus. MacLaughlin U.C. Reserve, California, USA

The distinctive conical nest entrance of Dorymyrmex bureni. The varying colors of soil particles result from the ants digging down through different soil layers. Archbold Biological Station, Lake Placid, Florida.

Formica obscuripes thatch mound nest. A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate. Sagehen Creek, California, USA