When do female and male ants mate?

Most all ants mate in one of two ways. The first is known as the male-aggregation syndrome. At a time usually triggered by environmental events such as a large rainfall, the males and unfertilized queens, which have been patiently waiting underground, suddenly take to the air and swarm in what is commonly called the nuptial flight. This swarming often appears as a column of flying ants rising off the ground. The queen is usually inseminated in mid-air and then flies off to a locale where she breaks off her wings and begins to dig a hole either in the ground or in plant material, which will become her nest. She lays her eggs and remains with them until they hatch, living off of her own body reserves. Eventually they will hatch and become the first of her workers that will take care of her and the colony as it increases in size and numbers.

The female-calling syndrome has queens aggregating at the surface of colonies and calling males to them via pheromones. There are many exceptions to this basic description of mating. For example, some females are inseminated on the ground and then fly off to find their nests. With another species, the males will be swarming close to the ground waiting for females to emerge from their colonies. When she appears, they surround her in a rolling, writhing ball of males until the newly inseminated female breaks out of the ball after about 20-30 seconds and flies away to find a nest site.