A busy trail of Odorous House Ants, Tapinoma sessile. The trail is maintained by a chemical laid down by ants as they pass. Urbana, Illinois, USA
Formica obscuripes nestmate workers engaging in trophallaxis, or the social sharing of liquid food. This behavior does more than merely transfer food. Ants also use it to pass chemical signals among each other, and research has shown that trophallaxis helps the colony maintain a cohesive identifying odor. Wisconsin, USA
A column of Eciton rapax, the largest Eciton species, marches across the Amazonian forest floor. Jatun Sacha reserve, Napo, Ecuador
