The photograph above shows ants (Lasius niger) guarding aphids while the aphids suck sap from a rose bush. The aphids get too much sugar from the sap and excrete it (this liquid is called honeydew) and the ants lap it up; drinking some themselves, and taking the rest home for their nest mates and grubs. Ants were farmers millions of years before humans even existed.
The tip of every leaf was guarded by at least one ant, and other ants patrolled over the aphids, and up and down the stems. Any other insect, or even a camera strap would be nipped and squirted with formic acid. So the aphids are free to suck in peace and the ant gets a sugary reward. And the rose bush? Well it was quite a big bush and a short time later it had many fragrant blooms.
In temperate regions there is little visible ant activity during the winter. As the temperature rises sexual - males and queens - are produced, and these have wings. Sexuals from different nest are released at the same time. The conditions at the time of release
are usually warm, humid and still air and moist soil. This synchronous release from different nests prevents inbreeding. These mass flights of sexuals provide a good meal for birds, spiders and many other predators.
The males and queens fly off and mate. This is the only time the queen will mate, and the sperm she receives in this mating must last her a lifetime of egg laying, which may be more than 10 years.
After mating the queen lands and searches for a nest site. Before digging into damp soil she breaks off her wings. She will never need them again, and will probably never see daylight again.
She digs a small chamber in the soil and lays her first batch of eggs. The energy for this comes from the degeneration of her flight muscles. She tends her batch of white, sticky eggs, and when they hatch she feeds the larvae. During this time she doesn't eat or leave the chamber.
Once her larvae have pupated and hatched out as sterile female workers they will take over all the nest duties, and forage for food, leaving the queen free to concentrate on her only duty now, which is egg laying. The first workers are usually smaller than normal size for the species.
This is the typical life cycle, but there are variations. In the more "primitive" species the queen may forage in the early stages of the nest. In other species colonies may bud off the main nest to become satellite colonies. Some species raid other nests for slave ants which they take before the slave has hatched into an adult.
Communication is mainly done by chemicals called pheromones. There are chemical trails to food sources, trails during exploration, and chemical alarm warnings.
The chemicals are produced in various glands, e. g. cloacal, Dufor's, poison, rectal, and tibial. Grooming and trophallaxis (liquid food exchange) also spread chemicals of recognition and queen condition throughout the colony.