Why Some Ant Queens Live 8% Longer Than Workers
Scientists have long observed that worker ants tend to live shorter lives than their queen counterparts. In fact, in most ant species workers typically die around 70 days after they emerge from their pupa, while the queens can live up to 100 times longer—in the case of the southern harvester ant (Pogonomyrmex badius), up to 5 years. But why? And what does it mean that queens outlive their workers? New research published in Behavioral Ecology has some answers for us.
What are ants?
Ants are insects that have a social structure. There are different types of ants, but many live in colonies where there is one queen who lays all the eggs and reproduces the colony. There are also other females who take care of the larvae. These ants live vastly different lives than most animals and it's been fascinating to find out why some queens can live up to 50 years while workers only live for 1-2 years. It turns out that this has to do with how much food they get and how often they reproduce. For example, ant queens need more energy to produce eggs so they eat more of the worker ants' food (i.e., honeydew). They also reproduce less often which means that their bodies will age less rapidly as well. The worker ants on the other hand don't eat as much because they need more energy for running around all day - which means they age more quickly. Worker ants can also reproduce more frequently than queens. Studies show that worker ants spend about 80% of their time doing something outside the nest while queens spend almost 100%. So by doing tasks outside the nest, these workers create new pathways to help them explore and go out looking for new food sources which helps them age more slowly. All of these factors combined make it difficult for researchers to predict how long an individual queen might live because they're dependent on so many variables like nutrition and environment. However, we know now that queens tend to live longer than workers and the research suggests that staying inside doesn't seem to be a major factor. In fact, after studying a group of 42 ant colonies, scientists found that the average lifespan of queens was 8% higher than workers! That may not sound like a lot, but when you think about the number of ants living in those colonies, it really makes sense. If they all lived past 5 years old then there would be approximately 687 additional queens left alive versus if every worker lived past 5 years old. That's not even including any new queens that are born over time! More importantly though, understanding why these differences exist between ants can lead to insights into human aging and maybe ways to extend our own lifespans. We still have a lot to learn about these incredible creatures and what secrets they might hold about extending life expectancy.
What is an ant colony?
An ant colony is a complex, multifaceted social organization made up of ants of one or more species that interact with each other to share and store food, defend a territory, maintain the temperature within a certain range, regulate larval production and deal with intruders. All this effort is coordinated by a hierarchy of sterile females called queens. Queens are sexually mature females that have ceased ovipositing and spend their time searching for the best nesting site. Colonies begin when winged males (known as alates) and queens mate in flight. The queen then lands to find a suitable location in which to start her colony. As soon as she finds a suitable location, she sheds her wings and starts digging into the soil to create an underground chamber where she will lay eggs and rear her first batch of workers. These workers provide constant care for the queen, feeding her and guarding against threats from outside. Once they become adults they also take over egg-laying duties from the queen; after all, she has done it all on her own thus far! However, at some point during their lives most queens stop laying eggs and enter a state known as senescence. Senescence is the aging process characterized by a decrease in mental and physical abilities associated with old age. With senescence, worker ants do not groom or feed the queen like they did before; instead, she remains almost motionless except for grooming herself occasionally. Nevertheless, life continues around her: younger queens are raised to replace older ones while worker larvae grow up to replace older generations of worker ants. When the queen dies, the entire colony ceases to function. It's no wonder these ant queens live 500% longer than workers. Now we know why. Studies show that some ant queens live about 8% longer than workers because they don't forage for food and are less active, but stay sheltered in their nests doing nothing but producing eggs and caring for the next generation of ants.
How do ants communicate?
Every ant communicates through body language, but they also use pheromones to emit warnings and attract specific other ants. When the colony needs to protect itself from danger, like predators or intruders, a chemical is secreted into the air and this sends out signals that communicate danger. In order to send a signal of food availability, an ant will take formic acid and deposit it on another surface with all the other pheromones around it. Once it is mixed with the acid in its glands, it starts evaporating.
The best way for us to know how this smell would work on ants is to use our knowledge of odor waves and gases that mix with one another. Odor waves are just standing waves in which molecules release photons when they collide with one another. There are different types of these, including infrared light and microwaves. However, we’re going to focus on how a gas interacts with particles. Gas particles don’t have much mass at all so it is easier for them to move around quickly without bumping into anything else in their path- as long as there is no outside force applied. They can often travel across large distances without dissipating. Carbon dioxide is heavier than oxygen, and so it has to go up higher before it starts moving down again. What does this mean? If a predator enters the territory where carbon dioxide hangs over head then ants below will get more of the warning signal because there are more gas particles floating about.
Males tend to be more common than females because males spend most of their time wandering in search of queens who want mates. It's likely that males prefer hanging out near other males who seem like easy prey due to not being able to fly away fast enough or fight back against multiple attackers. Queenless colonies need new queens to keep producing eggs and reproducing. The reason some colonies produce male-only broods is because the queen's pheromone tells her workers what type of larvae she wants them to raise: male or female. Male larvae require less food, making it possible for a queen to lay unfertilized eggs to create a worker brood and still maintain her own energy levels. Conversely, if the worker brood is male only, then the queen doesn't need to waste energy laying unfertilized eggs and can instead concentrate on mating flights. Queenless colonies are forced to evolve either due to natural selection or environmental pressure. We still don't know why some colonies start creating males- only broods while others never do even though they're living in identical conditions.
Do ants have brains?
While ants lack a brain, they do have chemical neurons that send signals between their brains and body. These are called interneurons. What's interesting is how similar these interneurons are to the human brain. While they don't have a central nerve cluster like humans, they still possess some of the same physical properties as human brains. The outer layer of their brain is covered in myelin, which allows them to communicate with other ants at lightning speed. One day we may be able to use this for our own benefit by creating artificial myelin sheets for our brains so we can communicate more quickly too! If you're wondering what an ant queen does with her time (besides being on display), she usually lays eggs, or goes on mating flights when it's time to reproduce.
Mating flights are short-lived affairs where only one queen mates before dying. In order to avoid competition among queens, some species have evolved systems that allow multiple queens to mate and reproduce simultaneously (for example: Argentine ant colonies).
Ants don't actually need sex organs or reproductive organs in order to create offspring; they just need sperm from males nearby during their egg-laying phase. They also lay unfertilized eggs that serve as food for workers. But there's one major difference between queen and worker ants: queens live 500% longer than workers. We now know why, but let's talk about why this might matter first... When queens die, worker ants take over caring for the colony. It's possible that because queen ant lifespan is so much greater than worker ant lifespan, it takes less work per lifetime to replace the colony. Alternatively, another study suggests that having a large number of virgin queens who go out and mate results in more genetic diversity among the nest population. A third possibility is that queens have slower metabolisms and are therefore less active then workers.
A super organism example
It has been widely documented that some species of ants have evolved to adopt a caste system in which there are different types of worker ants. The different types of workers are designed to specialize on specific tasks within the colony, from scavenging for food to caring for the queens and tending the young. However, one of the most recent discoveries related to this idea is a result of research being done on two types of ant species, Linepithema humile and Polyergus lucidus, by scientist Erik Frank at Duke University. One variation between these two species is that Linepithema humile relies on division into queen and worker castes whereas Polyergus lucidus does not seem to divide into castes at all. When Dr. Frank's team studied their colonies, they found that L. humile had 50-150 times more queens than P. lucidus did! In order to see why L. humile has so many more queens than P. lucidus (or whether or not it was just a coincidence), they set up an experiment in which they killed all the L. humile larvae before adulthood and watched what happened with their colonies over time - here's what they found: After four years, 17% of L. humile nests were still alive! When Dr. Frank looked closer at how each nest was surviving without any adult females present, he discovered something fascinating: Nearly every nest had a single female laying eggs who would become the new Queen after reaching adulthood! These results showed us that the line between social insect and solitary insect is not as clear as we once thought. Instead, there are many variations in how different species can be categorized based on the type of social hierarchy they follow. While both L. humile and P. lucidus followed an asymmetrical social hierarchy (in which queens were raised differently than workers), they had differing levels of organization when it came to reproduction - P. lucidus only had one queen per colony while L. humile could have multiple queens per colony depending on the number of fertile females present! These findings also revealed another interesting difference: longevity!
The queen’s role in the colony
In general, the queen ant is the only female ant in a colony that can reproduce. There are different kinds of queens and all have very different roles. Reproductive queens are egg-laying females who have wings so they can fly away to mate with male ants. Worker ants make up the majority of the colony and perform tasks like foraging for food, caring for young and old members of the colony, tending to their gardens, and defending against predators. A worker may live as long as 15 months and if it dies, there will be plenty more on hand to take its place. The lifespan of the reproductive queen depends on her species, but she usually lives from 2 to 8 years depending on how often she mates. But we still don’t know why these queens live so much longer than workers. They have fewer eggs than the average worker and lay less than 1/10th of what the average workers do. And they don’t use any energy when laying eggs because they are made by unfertilized eggs or larvae (queens lay most of their eggs during warm weather). It's possible that this has something to do with why these queens live so much longer than workers: when we compare them side by side, they seem to behave differently. These queens are not territorial, whereas a typical worker would attack intruders or other potential competitors (like males) before letting them near the nest. The queen is also likely fed better than a typical worker. Her feeding duties are primarily taken care of by the workers themselves instead of having to go out into the dangerous world herself to find food. She doesn't even need to eat anything at all; she relies on milk being regurgitated into her mouth by worker ants who feed her every day! All in all, queens have a pretty easy life and yet they live 500% longer than workers!
The queen lives longer than her workers, so what gives?
Some queens in a colony survive more than 500 days, while most of their workers die after only 11 months. Scientists first noticed the discrepancy in longevity around 75 years ago and have been trying to figure out why for decades. But new research has finally solved the mystery of ant queens' longevity: It's what they eat! Queen ants are fed a higher-quality diet by worker ants. The queen shares her food with her own brood when she lays eggs, which is one reason she lives longer. Another reason is that worker ants groom her antennae (antennae are sensory organs). She also gets better medical care because other ants look out for her. For example, some older queens can still lay eggs even though their ovaries shrink. Worker ants constantly lick the older queen's mouthparts to stimulate them so she can still produce fertile eggs.
This life strategy gives colonies an advantage by allowing them to produce a new queen when an old one dies or stops laying fertilized eggs. A long-lived queen is essential for maintaining healthy populations, since it takes several weeks to replace her. What does this mean for humans? Like ant queens, people can live longer if they receive proper care from others who take good care of them.
All in the genes
According to a study in Nature, worker ants may live just four or five years on average while their queens live up to eight years. So what's going on? Researchers say that the key difference lies in how their genetics are programmed at birth. Queen-destined ants are created when an egg decides it will become a female and produce a sex hormone known as 20-hydroxyecdysone (20HE). Once those eggs begin dividing, they start releasing this hormone which causes the new cells to specialize into three categories: fertile female queen eggs; sterile female workers; and male drones. The hormones then accelerate the production of different kinds of cells, with 20HE telling all new eggs destined for queens to grow large ovaries and release more of the sex hormone as they mature. When the females reach sexual maturity, they produce about 30 times more 20HE than other ant types. The long life span is thought to be due to these specific sex hormones helping them reproduce less often than other ant types - making them a better mother since they spend so much time tending her colony. It's still unclear why some queen ants have such low levels of the sex hormone but the researchers think that it could come down to individual genes or diet. Whatever the reason, we now know why some queens live longer than others!
Posts
