Have you ever stopped to observe the ants rushing through the cracks in the rocks or the grass? As a class of highly social insects, ants cooperate with each other and perform their duties efficiently to complete the work of nesting, foraging, cleaning and feeding offspring. There are more than 10,000 kinds of ants that have been recorded in the world, and more than 600 kinds of ants are distributed in my country. Among them, the more common ones are burrowing ants, yellow ants and black-brown ants.
In rainforests all over the world, there is a very peculiar class of ants that maximizes their ability to unite and cooperate: they often go out to their nests to hunt prey many times larger than themselves; they use their bodies to build “buildings” of various shapes… …This peculiar ant is the army ant.
Army ants are a general term for a class of ants, with about 400 species, mainly including the army ants living in South America, the spear ants living in Africa, and the double-segmented army ants living in Southeast Asia.
For the past 17 years, American entomologist Daniel Daniel has been working on army ants. The army ant’s extraordinary adaptability attracted him. Even though his research team would spend weeks tracking the colonies, often enduring the bites of army ants, they still enjoyed it. The collective hunt of army ants may be one of nature’s most spectacular sights. As Daniel’s team explored the rainforests of Costa Rica, Kenya and Venezuela, they repeatedly saw the ground suddenly move like magic. These “moving grounds” are nearly 20 meters wide, and they are the army of army ants surging like a torrent. They go one after the other through the fallen leaves and climb the vegetation in search of any tasty prey. As soon as one of these “little warriors” encounters a suitable prey (perhaps a katydid or an earthworm), it immediately sends out a chemical signal to summon other companions. Afterwards, they assemble with extraordinary speed, holding their prey under control and breaking it up into small pieces suitable for handling. According to statistics, in one day, an army of army ants can prey on tens of thousands of arthropods and other invertebrates.
Army ant colonies break into small groups when attacking, and then regroup with a full load of loot after the battle. At the other end of the army of marching ants, new warriors will continue to join the battle. The trajectories of these army ants meander through the rainforest like highways, and the width of the trajectories is even more than 100 meters. According to these trajectories, you can imagine the grand occasion of army ants attacking their prey.
The meandering “highway” is the army of army ants surging like a torrent
A katydid unfortunately became the prey of these “little warriors”
There are also other species of ants on the army ant diet, especially the larger carpenter ants
Antbirds that gather around a colony. For these antbirds, the marching ants have become out-and-out “delivery boys”
Army ants are the most numerous animal groups on earth, and some colonies living in Africa can reach 20 million individuals. There are 500,000 army ants living in South America. They can be found in subtropical regions of Mexico to tropical regions of Brazil. The diet of this army ant is particularly rich, including katydids and cockroaches in the class of insects, centipedes in the class of lipopods, and spiders and scorpions in the class of arachnids. They also prey on some larger arthropods. However, other species of ants, especially the larger carpenter ants, are most prominent on the army ant’s diet. As the name suggests, carpenter ants will nibble on the branches of trees and carve out promenades as dwellings. When the army ants attack the carpenter ants, the battle tends to last for hours. Initially, the carpenter ants can also block the entrance to the nest, keeping the marching ants out. However, under the fierce attack of the army ants, all the barriers will collapse, and the brutal looting of the army ants will follow. The army ants will take away all the adult ants and offspring of the carpenter ant, and the kingdom of the carpenter ant will die out.
The army of army ants acts collectively, and wherever it goes, it can be said to be “chicken flying and dogs jumping”, and other small animals will flee everywhere, so army ants are also called “repelling ants”. Some fleeing prey, even if they escaped the killing of the army ants, still did not escape the danger, because there is a class of birds we call “antbirds” that gather around the ant colony, and they will hide and wait for the opportunity to prey escaped insects. For these tragic insects, it is really “escape from the wolf’s den and into the tiger’s mouth”. Some antbirds are highly specialized, tracking ant colonies in specific areas of the rainforest, and even feeding only when the colonies pounce on their prey. For these antbirds, the marching ants have become out-and-out “delivery boys”.
In addition to antbirds, some parasitic flies also take advantage of the fire. Some of them hovered over the army of army ants, like small helicopters, and some stopped on branches or leaves to wait for an opportunity. When the time comes, they swoosh down and pounce on the fleeing arthropods to lay their eggs on the poor creatures. Afterwards, the fly eggs hatch into fly maggots, which start inside the prey and nibble them down into an empty shell.
In addition to antbirds and parasitic flies, there are many animals that rely on army ants to make a living, such as the Brinell ants among the army ants. That is, army ants support hundreds of species of “eaters.” Since the army ants’ food is more abundant, these “diners” are only enough to eat their leftovers.
social division of labor
When you observe army ants, you will find that they are different in size, shape and color, and are divided into different grades, which is a very common phenomenon in social insects. Different grades not only look different in appearance, but also have different social division of labor.
The soldier ants of the army ants are larger, with ivory-colored heads and a pair of menacing knife-like upper jaws, and they will occasionally show off their fangs and claws. When encountering a natural enemy invasion, they will pierce the skin of the natural enemy with their upper jaws, and sometimes use the sting to inject the venom into the body of the natural enemy. The upper jaws of soldier ants have a very strong bite. In traditional medicine in some countries, doctors sometimes arrange soldier ants in a row on the wound of the wounded. Once the upper jaws of the soldier ants fix both sides of the wound, the doctor cuts off the soldier ant’s body with a “click” sound. Even if the body is lost, the soldier ants will not release the upper jaw, which plays a good role in suturing the wound. Soldier ants are the guards in the ant colony. They do not participate in hunting, nor are they responsible for other day-to-day affairs in the ant nest. They are only responsible for protecting the territory and the safety of the ant colony.
Soldier ants are large, with an ivory-colored head and a pair of menacing knife-like upper jaws
Worker females have extra-long and powerful hind legs that are disproportionate to their bodies, which allows them to carry huge objects
In second place are worker females, which have a uniform brown body color and belong to the porter class of the army ant dynasty. Worker females have extra-long and powerful hind legs that are disproportionate to their bodies, which enables them to carry huge objects. When the prey is too large to be moved by a single army ant, they will move the prey in a cooperative way. Studies have shown that army ants are extremely efficient in teamwork, and the weight of objects they carry together is far greater than the sum of the weights of the same number of individuals carrying objects individually.
Soldiers and worker ants, although distinctive and eye-catching, are relatively few in the colony. The most numerous army ants are the worker ants. Worker ants do everything, find food, feed offspring and queens, build nests, etc. are all done by worker ants. Worker ants have black heads and chests, and vary in size. While not as threatening as soldier ants, worker ants can also sting humans. An entomologist was studying army ants in Venezuela when he felt several raindrops falling on him from a tall tree. When he found out it was actually army ants and quickly brushed them away, he was stung by the slipping army ants anyway. About an hour later, the unusually severe pain caused him to twitch.
Teamwork in army ants goes far beyond hunting and group transport. “Every mountain opens a road, meets water and builds a bridge”, in this respect, the army ants can be called “masters”. When an army ant stumbles into a small gap on the road that the army ant must pass, as long as the army of army ants keeps passing through and maintains a certain amount of circulation, it will stay in the small gap and treat its own body as a As a stepping stone to ensure that your companions can pass safely and quickly. When the gap is too large or encounter other obstacles, the army ants will bite each other’s bodies and build an “ant bridge” to save the crawling distance. The construction and dismantling of this kind of “bridge” is extremely fast, often in tens of seconds. The “ant bridge” is not static. The length of the “ant bridge” increases as the number of army ants increases, and the distance between the ant colony and the target is continuously shortened. The researchers found that dynamic ant bridges do not always achieve the shortest distance. Often, after the ant bridge is extended to a certain extent, the number of ants participating in the construction of the ant bridge will not continue to increase, and the length of the bridge will also stop increasing. The researchers believe that the army ants appear to use operations research in the bridge-building process. Since the ants participating in the bridge construction cannot participate in other work, once the ant colony finds that the number of ants invested in extending the bridge is out of balance with the number of ants required for other work, they will stop investing more ants in building the bridge. When army ants pass through a narrow path, such as a thin branch, they converge on both sides of the branch to form flanks, widening the path in this way and allowing the colony to pass quickly.
Early natural scientists attributed this phenomenon of collective cooperation to the reasoning abilities of army ants. But recent research has shown that this complex coordination is achieved by translating some simple rules into large-scale behavioral associations. The rule is: don’t move when your mate walks past you. The mutual agreement seems simple, but it can realize extremely complex cooperative behavior.
Tens of thousands of marching ants work together to build various “bridges” with their bodies
Tens of thousands of army ants work together to build various “buildings” with their bodies, like insect building blocks. As long as you have enough perseverance and a little luck, you may be able to follow the footsteps of the army of army ants to find their old nests-the “high-rise buildings” built by army ants with their bodies. It can be said that this is the masterpiece of the army ants as architectural wizards. Unlike most ants, army ants do not build permanent nests in soil. Instead, they build nests with their own bodies, known as camping nests. Some army ants build their nests entirely on the ground, while others hang from tree trunks or at the base of large trees, sometimes up to 1 meter in diameter.
Army ants don’t build nests like most ants do, they use their bodies to build a living nest, or campsite. They tend to roost in tree trunks or small burrows. Camp members grab each other’s legs and build an organized ball-like structure. The oldest worker ants are on the outside, and the queen ants are on the inside. When the ants outside sense movement, the soldier ants quickly gather to defend the nest
Take a closer look and you’ll see that this design is perfect! Army ants are connected to each other by hooked protrusions on their feet, forming chains and further webs, much like the scaffolding that surrounds the outer layers of a building on a construction site. The internal passages and nursery are also formed by the interconnected bodies of the army ants. The smallest worker ants stay in the nursery to care for the young. The nest also automatically regulates the temperature. During the sweltering noon, the outer army ants will slightly loosen their connection to each other, making the nest as a whole fluffy, so that the air can circulate better to achieve cooling; on cold nights, the outer army ants will tighten each other. The link conserves heat and provides a warm and comfortable growing environment for the developing larvae.
The researchers had witnessed more than 100 such camps during their months of fieldwork, and one of them impressed them. The researchers spent days tracking a type of army ant. Finally, one night, they found the colony of this army ant. I saw that the ant colony used a fallen branch and two large leaves to build a peculiarly shaped nest on the open ground. The nest looks like a cathedral with three naves, and the marching ants come and go like tourists visiting St Paul’s Cathedral. This is really a delicate building, worthy of our study and study.
Army ants’ successful predatory lifestyle forced them to evolve into nomadic animals
What is home?
Some people may be curious that army ants have such efficient teamwork capabilities that they can build sophisticated and complex permanent nests like other ants. So why do they like to travel all the way and like to build temporary nests? The researchers’ answer: The successful predatory lifestyle of the army ants forced them to evolve into nomadic animals, like the ancient nomadic tribes that plagued farming peoples. Looting a village that has just been looted doesn’t make much money. Instead, it would be wise to quickly find new hunting grounds. In layman’s terms, it is “one shot for another place”. So what could be more convenient for a nomadic tribe than a camp that doesn’t require building materials?
The relocation of the camp generally begins in the evening. When a big drama is about to take place, the army ants in the camp will appear restless and increasingly excited. The army ants that had just returned from hunting were also driven out of their nests by the worker ants. What followed was a torrent of marching ants pouring out, and the camp soon disappeared. On a dark night in the rainforest, following the route of the previous raid, the army ants gathered again with their food and larvae, and a brand new camp soon formed. Of course, a group of grotesquely-shaped guests were behind them waiting to eat rice. Finally, the queen ant and her entourage also appeared. The queen’s travels are ostentatious and strictly protected. The queen ant is responsible for laying eggs and is the largest and most important member of the colony. Without it, the entire ant colony would fall apart. Therefore, during the relocation process at night, the queen ants have been surrounded by soldier ants and are closely protected.
long live the queen
The queens of army ants are very different from those of other ants. The queens of army ants are not only larger but also wingless. Most species of ants send many young queens on mating flights. These are the larger, winged individual ants we occasionally see in spring. Once fertilized, the young queen sheds her wings, burrows in the ground to build a nest, lays eggs continuously, and slowly establishes her own dynasty as the number of offspring continues to increase. A few years later, a new queen will be born in its dynasty, thus realizing the inheritance of the lineage. But this strategy didn’t work for army ants. Because the method of starting from nothing and from less to more is sure to end in failure for the army ants. So their strategy is to split the original colony in two, which is very similar to the splitting of honeybees. Each ant colony selects a queen and develops independently, thus forming a new army ant dynasty. Therefore, the queen of army ants is the rarest and most precious to the rest of the colony. The queen never leaves the safe colony and does not put herself in danger.
Army ant queens are not only larger but also wingless
Army ants can’t fly, which brings them troubles – it is difficult to perform fast and efficient long-distance migration only by crawling, and only through efficient migration can they avoid unsuitable terrain and habitats and find a more suitable place for survival . Genetic studies have shown that rivers are insurmountable barriers for army ants. This means that habitat fragmentation poses a serious threat to the survival of army ants. This situation, in turn, affects the diversity of the species that army ants hunt, and the well-being of many species that depend on army ants for their survival. If humans want to protect these incredible little creatures and their companions, it must ensure that they can move unimpeded through the tropical rainforest they depend on.