Lifecycle of an ant colony

From founding to death

The lifecycle of an ant colony starts with a tiny ant queen. If she is successful in mating and founding a surviving colony, she will be the mother of millions of individuals. But what does the lifecycle of an ant colony look like?

Even though ants seem abundant in nature, it is not an easy task to settle a colony. The competition is overwhelming – by every queen that succeeds lies hundreds or thousands dead, failing to do the same. They fall victims to predators, other ants, heat, drowning or other things dangerous to an ant. The queen that does find a place to settle, without competition nor predators, can dig her new chamber in the hopes of a future as ruling queen. (1)

For a more in-depth article about the queens and males of ants, read more about them here: Flying Ants

Just like individual ants develop in three different phases (egg, larvae, pupae), so does the colony. For starters there is the founding stage, where new queens mate with males and then found their colony. After the birth of the first workers the colony goes into the ergonomic stage. During this time, the focus is growth: expanding the nest, raise more workers and conquer territory. The third stage is where the colony is strong and stable and have the economy needed to produce fertile offspring – the reproductive stage. The colony then starts producing winged ants, males and new queens, to send out into the world. (2)

Let’s have a look at the different stages of a lifecycle of an ant colony.

1. The founding stage

During the years of colony life, workers are born all the time providing there’s nutrition, moist and heat around the nest. The workers are for most part infertile and can not lay anything but sterile eggs. The only ones who can actually produce fertile offspring is the queens and males, and these are only born during a specific period of the year. In the northern hemisphere, this means the summer season, ranging from early april to late summer. These eggs are larger than that of the workers’ and are treated better. When they eventually hatch these ants have large wings and impressive bodies.

In Scandinavia, the woodland ant (Formica) is the first one to mate, from early spring to early summer, followed by the carpenter ants (Camponotus) at the turn of the months of May/June. Lastly, the Lasius and Myrmica-species will mate from July to August. Some species have their nuptial flights as late as September/October, for example the ants of Stemma debile. All of the winged ants (also called alates) can be housed in the nest for several months, waiting for the big day to come. The carpenter ants usually have their alates raised before winter, which means they can wait up to half a year for the flight. (3)

Thousands of ants swarm during the nuptial flights

So, how does the nuptial flights actually happen? Generally speaking, the ants seem to have some sort of biologic sensor, a timer, that tells them when to fly away and mate. When time and weather is optimal, most ants of a certain species will take flight. A bunch of species prefer warm windless days in combination with high humidity. If you’re experiencing a warm day in the month of July with thunderstorm near in time, you might soon be looking at the nuptial flights of Lasius niger. The matings can occur early or late in the day, and species that are genetically close tend to ”schedule” their flights at different times from one another. This is to minify the risk of the two species mating. Of course, this isn’t always possible as there’s only that many great days in a year. (4)

Mating often takes place on bright surfaces, for example a white terrace-roof. It is something that’s shiny and visible from far away and therefore tempting to the ants. The males usually arrive first, enticing and luring the females with the help of pheromones. (5) And when a queen has mated with one or more males (depending on species) they will move towards the ground, break of their wings and search for a place to settle their new colony.

Other methods of colony founding

But this isn’t the only way colonies can be founded. Some species use different methods. A few European woodland ants makes the mating a much more protected affair. The queens do not fly away, but rather travel to the top of the anthill waiting for males to pass by and inseminate them. After mating the queens can return to the protection of the nest and start to lay eggs. This is one of the advantages in polygyne species (having more than one queen). But how does one solve the problem of expanding and settling new colonies? When workers have found a location for a new nest, they will take queens and workers with them and wander off to the site. From there they will found a colony (6). Some species even allow for inbreeding and never lets the queens leave the nest to mate. This way the number of ants can increase at an incredible speed, but the price is the risk of deformities. (7)

From egg to ant

Photo: Alex Wild.

Despite some species safe ways of founding new colonies, most ant species’ queens go at it alone. If they survive mating they will break of their wings with their legs and start digging where they think is a good spot. When her first chamber is finished she will seal it up and live alone in the dark for many, many days. Shortly after this she will start laying her first eggs, and during their time of development she will get nutrition from the breaking down of her wing muscles. The eggs are few, since she will be rearing them all alone without any food or help. The time it takes for the eggs to go through its development process varies depending on species, but as an example the ants of Lasius niger takes about 8 to 10 weeks. During this time she will tend to the eggs, feed them when they turn into larvae and then tend to them as pupae.

2. The ergonomic stage

The first workers are examples of how well balanced the economy of an ant colony is, even this early on. The ants are tiny and much weaker than the coming generation of sisters. This is the result of a well planned distribution of resources, and is incredibly important to the survival of the colony. More workers results in a more effective colony, and is to prefer before strength. The queen only has the capacity to create a certain amount of biomass, and therefore chooses to spread it out by creating as many offsprings as possible. The larger worker force, the less important each individual ant becomes. When the amount of workers and food available rises, the more ”normal” sized workers will appear from the pupae. (9)

The nanitics differs in other ways than just size in comparison with normal workers. They are very shy and stays out of danger if possible. Compare this with a large colony that can easily sacrifice workers to eliminate enemies. Young colonies need every single worker they can get to make sure the they survive the competitive surroundings.

The ant queen after the first workers

So, what happens to the queen after the first workers is born? She stops tending to the brood the way she has; feeding and cleaning. She instead focuses on her true purpose: the laying of eggs. Her role as leader of the colony is no more, and she will from now on be dependent on her children to care for her. Ant queens are not queens in the sense of leadership – they do not lead the affairs of the colony. But they are the most important individuals in the ant world, making them the center of care, food and protection. Because without the queen there will be no more workers.

If a colony manages to survive the period of the first generations of workers it will most probably succeed. With time the amount of workers will grow, the colony expand and new territories be conquered. When the colony has grown big enough it will be able to take care of larger preys and greater enemies. When colony growth has reached a certain level, it will transcend into the next stage. (10)

The elimination of ant queens

Lastly, the ergonomic stage is where surplus queens are eliminated. For example, the yellow meadow ant (Lasius flavus) founds colonies together with other queens. This way they get a boost in the founding stage because of the many egglayers, producing a lot of offspring. Eventually, when the workers are born, the game of thrones begins with the queens fighting and eliminating each other until only one is left. (11)

3. The reproductive stage

When a colony has reached an optimal size (depending on species) it is time to put the excess resources to good use – reproduction. The colony begins its work to produce new queens and males, or ”winged ants”. Some myrmecologists believe that males appear first in the nest, later followed by the queens. But this has not been scientifically confirmed and is hitherto only speculation.

Some species start producing fertile offspring as soon as they hit the ten workers-mark, whilst others must reach thousands of individuals. (12)

When the alates are grown and fly out of the nest to mate, the whole cycle starts over. The new queens will found new colonies and the males will die off. So how does the lifecycle of the mother nest end?

The end of the cycle

After many years the colony will eventually die. A queen of the species Lasius niger reached 29 years of age in a laboratory, to give an example of the length of a queen’s life. And if the species is monogyne the colony will die with the queen. No more workers are produced and fertile offspring is something of the past. Hopefully the queen has had many good years, being able to send many alates out to populate the Earth on her behalf. Hopefully there are a bunch of colonies out there carrying her genes, continuing her line.

Have you ever wondered why ants form colonies? What does a worker get from spreading their mother’s genes? Why don’t they lay their own eggs?

References

1. Bert Holldobler & Edward O. Wilson (1995) “Journey to the ants” p. 29-30

2. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 143

3. Per Douwes, Johan Abenius, Björn Cederberg, Urban Wahlstedt (2012) Nationalnyckeln “Steklar: Myror-getingar. Hymenoptera: Formicidae-Vespidae” p. 37-38 (Swedish)

4. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 151

5. Per Douwes, Johan Abenius, Björn Cederberg, Urban Wahlstedt (2012) Nationalnyckeln “Steklar: Myror-getingar. Hymenoptera: Formicidae-Vespidae” p. 38 (Swedish)

6. Bert Holldobler & Edward O. Wilson (1995) “Journey to the ants” p. 34

7. Bert Holldobler & Edward O. Wilson (1995) “Journey to the ants” p. 39

8. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 157

9. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 158

10. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 159

11. Per Douwes, Johan Abenius, Björn Cederberg, Urban Wahlstedt (2012) Nationalnyckeln “Steklar: Myror-getingar. Hymenoptera: Formicidae-Vespidae” p. 35 (Swedish)

12. Bert Holldobler & Edward O. Wilson (1990) “The Ants” p. 159-163 (Table)