independent

Sunday 22 October 2017

Nuptial flights of Black Garden Ants occur in summer

Black Garden Ants with cocoons concealed in a nest under a stone.
Black Garden Ants with cocoons concealed in a nest under a stone.

Jim Hurley - Nature trail

Nuptial flights of Black Garden Ants occur during the summer. Males and females take wing and mate while flying. Sometimes the numbers of flying ants can be so great that thousands of individuals can be airborne attracting gulls and other birds to feed on the insects rising from the ground.

To ensure successful mating, ants need to emerge from several nests in a synchronised way. It is believed that hot weather triggers mass emergences.

Following their nuptial flight, the males die. They only live for a day or two and their only purpose in life is to fertilise the virgin females during the brief annual, summertime nuptial flight. The fertilised females come to ground and, all going well for them, they can live for a long number of years.

Each female discards her now-useless wings, burrows into the ground and seals her burrow. She constructs a chamber and starts to lay eggs. She has no source of food and survives by digesting her now-useless wing muscles. Her eggs hatch into maggot-like larvae in a little over one week. The larvae are fed by their mother until they are mature.

When mature, the larvae spin cocoons of silk around themselves and undergo a process of metamorphosis in the cocoon before emerging as adult ants. These ants are sexless individuals. They break the seal on the underground nest and forage for food above ground. They feed their exhausted and starving mother.

If the female survives to this stage she is now the queen of an infant colony with her offspring supporting her. She gains condition, puts on weight and goes into egg production in a serious way with her offspring tending her, the new larvae and cocoons.

The colony grows in size, strength and complexity with the number of workers rising to thousands or tens of thousands over many years.

All her offspring are sexless so far. When the colony reaches a critical size, the queen can lay eggs that give rise to fertile males and females. As these mature, both grow wings.

On warm summer days, males and virgin queens from several nests take flight and pair up with partners from other colonies. They mate on the wing in mass nuptial flights. The males die. The fertilised females come to ground, shed their wings, burrow into the ground and the whole process of forming a colony starts all over again.

Corkman

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