Myrmecocystus honeypot ant species come in three basic color patterns, depending on the time of day that they forage. The orange/yellow species such as this M. navajo are nocturnal. These ants were photographed leaving their nest entrance to forage shortly after dusk. Willcox, Arizona, USA

Bull ants are solitary foragers, hunting alone even though they live in colonies. Here, a worker Myrmecia nigriceps descends a tree trunk in a eucalypt woodland. Yandoit, Victoria, Australia