In my post The Wonderful World of Ants, we discussed some general ant concepts. In this post, I would like to present an ant colony from its formation to death. Since there is enormous diversity in colony formation, I will keep it as general as possible. If you want to read more about the diversity of ant colony formation, I recommend The Journey to the Ants by legendary myrmecologists Bert Hölldobler and E.O. Wilson.
Nuptial flight
This story begins with an ant princess stepping out of her nest for the first time on a warm day. It is the day of her nuptial flight. The day she will leave her home forever and start her own colony. From the moment her queen mother laid her, she was destined for this flight. As she matured from egg to adult, the young princess-to-be dined on the finest food the colony could offer and was constantly doted on by her worker sisters. All of the effort her siblings put into her care was all for this very moment.
Her veil, composed of a pair of beautiful wings, lifts the soon to-be queen to the sky. It is the first, and hopefully, last time she will ever fly. Following the same path her mother and all those before her have, she advances steadfastly toward the sacred mating grounds. She was never taught how to fly or where to go: it is all pure instinct. As she reaches the ground where princesses become queens, she is met with a hectic display. Hundreds of male ants, known as drones, frantically compete for the chance to mate with hundreds of other princesses. This is the whole purpose of their lives. To fail now would quite literally be the end of the line.
Princesses are not content with just one drone. A queen needs to produce far more offspring than a singular drone could give her. So, the princesses allow drone after drone to mate with them until their sperm banks or oval bags are filled. After the sacred act is complete, they give a signal either through pheromones (hidden scent messages) or by shaking their bodies that they have had enough. Our determined princess is no different. She joins the frantic mating ritual, allowing only the drones she deems fit to mate with approach her. Once she is finished, she too gives a signal that she is done. She has completed the first, and most important step in becoming a queen. Crawling away from the ritual, she engages in one last rite to signify to the world that she is a princess no more. She uses her middle- and hind-legs to tear her wings off, allowing them to fall onto the ground next to her. She is no longer a princess; she is a queen.
Our princess was a lucky one; she knew exactly where to go and arrived right on time. Other princesses are not so lucky. They arrive too late or get lost along the way. By the time they find their way to the mating grounds, the nuptial flight is finished. Late-comers will never mate and become queens. The line ends with them. They will wander aimlessly until their lives reach their ends, either through natural means or at the mercy of a hungry predator. As for drones, they live and die for this singular act. Those that mate successfully perish completing their life mission. The unfortunate ones who could not complete their duty suffer the same fate as unmated princesses.
Founding of a colony
The nuptial flight was only the first barrier for this new queen. She now needs to find a suitable spot to dig a nest and start her colony. This is much easier said than done. For the first time in her life, she is a lone ant in the world. She has no workers to protect her, no other ant to rely on in times of need. As she journeys to find a haven, she hides from birds, dodges lizards, weaves through other insects, and evades human feet. Unfortunately, threats come in more forms than a large predator. She must keep an eye out for other new queens who are also looking for a place to make a home. Colonies that are too close to each other will result in an all-out war, and at this early stage, the victor will be the queen who hatches an army first.
Our fearless queen luckily finds a nice patch of dirt that will conceal her from the dangers of the world for now. She burrows into the soil, creating a small cavern. Finally, this is the start of her new home. She will wait in this hole from anywhere between a few days to months until the eggs in her ovaries fully mature. During this time, she will only rarely leave the nest to forage. Unlike her worker sisters back home, queen ants are much larger and carry a good amount of fat on them. This fat will act as her main source of food until her first workers are fully matured.
The first workers
When her eggs are developed, the queen lays them in the safety of her nest. Thus begins her first job: caretaker. The survival of the first workers, and the colony, depends solely on her ability to properly care for her first eggs. She feeds them using the fat reserves that she had been surviving on for the past few months. But as anyone with children knows, feeding is only a small part of raising children. Cleaning also becomes a large part of her job; an unclean nest invites infections. Many queens before her have lost their lives to fungal infections caused by fungi that love to grow in dark, damp environments.
The job is exhausting for this new mother. The first workers may take up to 10 months before they are fully developed. Queens who do not have a sufficient amount of fat reserves resort to cannibalism of their first eggs. Some are bold enough to leave the nest, but most are met with a grisly fate in the outside world without protection. Our queen has luckily developed properly and does not need to leave her safe haven. She nurtures her workers from eggs to larvae, then pupae, and finally adults. For the queen who has been alone in the world relying solely on her instincts, the emergence of the first workers must be a welcoming sight.
True to their namesake, the workers immediately get to work. They open a hole to the colony, letting light in for the first time in forever. Some search for food to feed their ever-tired mother, while others stay behind to care for their undeveloped sisters. Our exhausted queen, who has grown to prefer the darkness, secludes herself in the deepest part of the colony. She has succeeded in her nuptial flight, survived alone in the harsh environment, and successfully raised her first offspring. Now that her adventurous days are over, the only thing she will do for the rest of her life is being pampered and laying eggs. She evolves from an individual to a member of the colony.
The colony grows
With the first few workers developed, the colony can now begin its true growing phase. A constant supply of new eggs ensures that the number of workers is ever-increasing, even as some die. To hold all of these new members, workers dig further down into the soil. As the nest grows bigger, cleanliness becomes even more important. The workers dedicate a space to store and clean dead bodies of kin and prey to prevent the spread of disease. Workers cannot work 24/7, so rest chambers are constructed. The queen, who produces eggs nonstop, is relocated to the deepest part of the colony, and her eggs are moved to rearing chambers. What started as a single queen quickly grows into a veritable metropolis with worker ants performing increasingly complex jobs.
Eventually, the colony has the resources to produce different castes of workers. As soon as she lays her eggs, the queen determines if her kin will grow into a soldier worker caste (called majors), a standard worker caste (minors), or perhaps more specialized castes. The division of labor is handled by the workers. Some are tasked with digging new chambers for the colonies, some take care of new workers, and others venture out into the environment in search of food to feed their sisters and queens. Soldiers guard the entrance of the colony and escort foraging parties. The division of labor even changes depending on the age of the worker. Younger ants are restricted to jobs inside the colony as they lack the experience to hunt. Conversely, older ants are often sent outside the colony as much as possible. The older they are, the more experience they have, but the higher the chances that they could carry diseases.
While life may seem easy for the colony now, danger still lurks around every corner. More numbers equal a greater chance of colony-ending diseases. The workers are diligent in cleaning each other and executing any sister who shows a hint of disease. A colony as large as this is bound to be noticed by enemies. Slave-maker ants, whose goal is to steal a workforce from other colonies, raid the colony’s brood. Other insects disguise themselves as ants and trick the workers into using their precious resources to raise them (more on both of these things in the next post!). Territory wars with other colonies arise as the colony needs to gather more and more resources. Life is difficult, but the colony prevails.
Next in line
The colony has survived attacks from other insects, periods of starvation/dehydration, and the harshness of winter. It has weathered what life has thrown at it and grown large and strong. The only thing left for the colony to do is to ensure that its genetic code reaches the next generation by continuing the line. This goal causes an uneasy shift in the colony as a hidden rift between workers and the queen arises. While the colony is not a collection of individuals but a whole organism itself, there is still a powerful divide between the queen and her daughters. Every species on Earth has a drive to preserve its unique genetic code through reproduction. The queen has no issues doing this. However, her daughters, the sterile workers of the colony, have no means other than their mother to pass on their genes. This disparity between the reproductive powers of queen ants and workers leads to conflict. This conflict is not one fought with an uprising or coup. Instead, it is fought throughout evolutionary timescales that ultimately shape the colony’s behavior.
All workers have the potential to develop into a reproductive caste, otherwise known as princess, if fed the right diet and given enough attention. Throughout the non-reproductive phase of the colony, the queen emits pheromones that prevent the workers from raising a princess. To the queen, princesses take up precious resources and time that could be used to produce workers for the colony instead. This queen is lucky that she survived to found a colony, but this is not the case for a vast majority of princesses. She is only interested in producing princesses when she feels that the risks are much lower than the benefit of making workers. This is not the same logic the workers use though. If they had their way entirely, the colony would constantly produce princesses every season. They need to in order to spread their genes. While it seems that the queen holds most of the power when determining when princesses are born, the workers have the trump card. They are the ones that feed and nurture their siblings. They could choose to let any sister who is not fated to be a princess die. Thus, we come to the evolutionary crossroads, the point in time when a colony decides to become reproductive. For reasons that involve complicated terms such as kin conflict and some math, this decision favors the workers’ wants over the queens’ (for those curious enough to reach about this in depth, you can find the entire explanation in this article).
Nevertheless, the colony enters its reproductive phase. Workers lovingly nurture future princesses who will one day embark on their own nuptial flights. As for drones, they need far less work. Female ants are produced by combining an egg and sperm, but drones are the result of single, unfertilized eggs. They will develop into much smaller versions of their sisters. When the weather is warm and wind conditions are just right, both newly developed princesses and drones will fly off from the colony to face the hardships of life.
The death of a queen
We have followed this colony from the birth of a princess, crowning of a queen, building of a nest, and continuation of its line. The final step of this journey is a fate that every organism that has ever lived eventually faces: death. A colony’s last days begin with the death of its queen. Our elder queen has lived to be five years, which is considered ancient in the timespan of ants. In the eyes of the workers, the queen must have been an immortal being for she has existed for their entire history. With her death, they continue life without purpose. They dispose of the queens’ body as they would any other worker. They raise the last eggs the queen has laid. They collect food and water, take care of their kin, and await the day that the last of them die. Slowly, one by one, workers die of predation, old age, or disease. No new workers are made to replace them, so the colony grows smaller. Eventually, only a handful of workers remain. Small in number, they can no longer defend themselves; they join the last of their sisters as they succumb to the natural world. Thus, the colony ends.
While no living ant remains in the now-empty nest, it is not quite the end. Through years of hard work, this colony has dug an extensive network that has been converted into a nutrient-rich environment both inside and outside of it. This environment allows other organisms, such as plants, to take root in the remains of the colony nest. Insects, who were once chased away by soldiers of the colony, now find refuge in its hidden tunnels. Where the lives of many end, many more live. The death of a colony is not met with fanfare, but instead the quiet thanks of the next generation of creatures that live off everything the colony has accomplished.
Bibliography
Hölldobler, B., & Wilson, E. O. (1998). Journey to the ants: a story of scientific exploration. Harvard University Press.
Lafleur, L. J. (1941). The founding of ant colonies. The Biological Bulletin, 81(3), 392-401.
Bourke, A. F., & Ratnieks, F. L. (1999). Kin conflict over caste determination in social Hymenoptera. Behavioral Ecology and Sociobiology, 46, 287-297.
Sondej, I., & Domisch, T. (2022). Abandoned Wood Ant Nests as Sites for Seedling Germination. Forests, 13(5), 764. https://doi.org/10.3390/f13050764
