Birth of an Ant Colony

How does an ant colony start? Who starts it?

Here I will describe just how an ant colony starts. There are in fact several methods of colony creation, and I will describe how a colony of Lasius niger ants is created and will include a brief description of other methods used by British ants.

Every summer, usually around late June to early August in the UK, great flights of winged black Lasius niger ants can be seen swarming outside nests, and eventually taking to the air; these are the synchronized annual mating flights of Lasius niger.

It is common for there to be two or even three separate mating flights during the summer, as some colonies seem not to release their winged members at the same time as many others. Regardless of that slight exception, the mating flights of ants is generally much a synchronised event within species and neighbourhoods.

During these mating flights the large winged queens, and smaller winged males will take to the air, following the thermal currents, in the hope of finding themselves a mate. They may mate in the air with the male perched on top of the queen, or they may mate on the ground. Once mated the queen will fly off to find a suitable nesting site, whilst the male will survive perhaps a day or two before curling up and dying; his only role in life fulfilled. The queen may go on to mate with several more males before finding a nesting site.

Once the queen has landed, she uses her middle and hind legs to “unhook” her 2 pairs of wings, these will be discarded on the ground and forgotten about. The reason why the queens do this is that the wings are of no use anymore. She will never fly again, and the wings will only become a nuisance to her. Sometimes the queen will not remove her wings, for whatever reason, but they will soon break off, or get chewed off by the workers.

Once she has found a suitable nesting site, the newly fertilized queen ant will urgently dig herself a tunnel leading to a small chamber. She will seal herself within in the chamber and, unless she is forced to, she will never emerge into the sunlight again. From this point onward her life is lived in total darkness and she will become acutely photophobic if exposed to the light henceforth.

The new queen may lay eggs straight away, (some species do, whilst others do not,) or she may wait until the spring. However, if she lays her eggs straight away, and the weather stays warm or mild, then the eggs will hatch within 8-10 weeks, (remember, we are discussing Lasius niger here, other species may take less or more time to develop their brood.)

Usually, at least as far as Lasius niger are concerned, the queen will create this new nest completely on her own, though it has been known for Lasius niger queens to come together and cooperate in the raising of the first brood. However, Lasius niger are strictly monogyne, meaning that each colony will only tolerate one parent queen. If more than one Lasius niger queen raise brood together, they will soon fight to the death once the first workers have hatched, until only one queen remains victorious.

Whilst the Lasius niger queen is awaiting the emergence of her first workers, she will neither eat nor drink on the whole, though she may eat a few of the eggs she has laid. Generally speaking though, she will live off the now defunct wing muscles in her thorax, which will breakdown and be converted into energy, and egg production.

When the first workers emerge, they are very small and timid, compared to the later generations of ant that will follow. They immediately begin to expand the nest, tend to the queen and brood, and eventually remove the seal from the chamber entrance created by the queen, and forage above ground for food. This is a critical time for the new colony as food will need to be gathered quickly in order to feed the near starved queen, who would have lost about 50% of her body weight, and to provide her with the nourishment needed to create more eggs. From this point on the queen will cease all other functions but will instead become an egg laying machine.

As future generations of ants are produced, they will be bigger, stronger, and more aggressive than their older sisters. After a year or so the colony will enter an exponential stage in growth when the population will rise dramatically. Once the colony is well established, which can take a couple of years or more, the queen will start to lay eggs that will turn into winged males, and later on, when the colony resources are plentiful, large winged queens will appear, and the whole cycle is started again.

There are several other methods that ants use to create a new colony. Some of the polygyne (more than one parent queen) species will be created by several queens who come together to start a new nest. Unlike a group of cooperating Lasius niger queens, Myrmica rubra queens will continue with several queens after the first batch of workers are eclosed and will continue to function as a single colony with each queen contributing to the egg production of the colony.

“Budding” is another method in which new ant colonies are created. An example of this is shown in the southern red wood ant Formica rufa. These ants can have over one hundred egg laying queens in each colony, and once a colony becomes large enough, one of more of these queens may leave the nest, taking hundreds, or thousands of workers and brood with her. They will start a new colony, usually not far from the parent nest.

Parasitism is another method by which newly mated queens of the species Formica sanguinea, the largest of the native British ants, may create a new colony. A newly mated queen will force her way into the nest of a smaller species, such as Formica fusca and snatch some of the brood. She will then create a sub-cell within the nest and defend it against the colony’s workers or queens. The queen may kill the parent queens herself, or she may wait until the brood she has snatched emerge, and they will associate themselves with the sanguinea queen, and kill the original queen themselves.

Lasius umbratus queens use Lasius niger nests to create their new colonies. These queens will locate a Lasius niger nest, hide themselves away some distance from it, and wait for an unsuspecting worker from that nest to pass by. The umbratus queen will then grab the worker, kill it, and use its body to cover herself with its own colony scent. You can sometimes see dark-coloured newly mated queens walking about with a dead worker ant in their jaws shortly after the mating flights. This is quite likely to be a Lasius umbratus queen preparing herself for her nefarious mission. She will then enter the Lasius niger colonies, acting submissive to any niger workers they meet, in an attempt to avoid combat. Eventually the umbratus queen is accepted by the niger workers as their own, and they will kill their original parent queen. However, umbratus queens are not always successful and are often attacked and killed by the Lasius niger workers as they try to gain access to their nest.

Lasius fuliginosus queens will raid the nests of Lasius umbratus incorporating themselves into the hustle and bustle of the host colony, usurping the resident queen. The umbratus workers will eventually adopt the invading fuliginosus queen as their own.  So, a colony can start as being Lasius niger, be taken over by Lasius umbratus and eventually becoming Lasius fuliginosus.

Formica sanguinea cannot start a new colony on their own and so will find and force her way into a Formica fusca nest, creating herself a little burrow within that colony. She then lays her own eggs defending them vigorously from the host workers. Once her own workers hatch, they will seek out and kill the host queen, though the sanguinea queen may kill her herself. Once the fusca queen is dead then remainder of the fusca colony accept her as their new queen.