Ants are distinguished from other insects by the combination of elbowed antennae, a strongly constricted second abdominal segment forming a distinct node-like petiole, a wingless worker caste, and the presence of a metapleural gland. They can sense with organs located on the antennae, which can detect pheromones (single compounds) and hydrocarbons on the outer layer of the body (a set of different compounds). The latter is highly important for the recognition of nestmates from non-nestmates. Also, they communicate with sound in the form of vibrations moving through the ground.

They live in colonies with well-defined castes that typically comprise a worker caste of sterile females and a reproductive caste of winged males and females. (Most queens and male ants (drones) have wings, which they eat after nuptial flight; however wingless queens (ergatoids) and males can occur.

Aphids secrete a sweet liquid called honeydew. Normally this is allowed to fall to the ground, but around ants it is kept for them to collect. The ants in turn keep predators away and will move the aphids around to better feeding locations.

Definitions: Myrmecology is the branch of entomology dealing with ants.
Myrmecochorous (adj.) dispersed by ants.
Myrmecophagous (adj.) feeding on ants.
Myrmecophile (n.) an organism that habitually shares an ant nest myrmecophilous adj., myrmecophily n.