Ants and the art of war

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Battles between different ant colonies are remarkably similar to military operations conducted by humans.

Mark W. Mofett is a Research Fellow at the National Museum of Natural History at the Smithsonian Institution who studies ant behavior. In search of these insects, Moffett traveled to tropical countries in both the Americas, Asia and Africa, describing ant communities and discovering new species, as detailed in his book Adventures Among Ants

The fierce battle looked as if a blur had fallen on both sides. The degree of brutality of the battle that came into my field of vision exceeded all imaginable boundaries. Tens of thousands of fighters rushed forward with frantic determination. Little warriors, dedicated to their cause, did not try to avoid collision even in the face of imminent death. The skirmishes were short and merciless. Suddenly, three undersized fighters pounced on the enemy and held him in place until a larger warrior approached and cut the body of the prisoner, leaving him crushed in a puddle.

I staggered back from the camera's viewfinder, convulsively sucking in the humid air of the Malaysian rainforest, and reminded myself that the fighters were not humans, but ants. I spent many months recording such battles with a portable video camera, which I used as a microscope, observing small insects - in this case the species of marauding ants Pheidologeton dtversus.

Scientists have long known that some species of ants (and termites) form tight-knit communities of up to several million individuals. These insects are characterized by complex behavior, including raising "domestic" animals, maintaining sanitary conditions, regulating movement and, most surprisingly, waging wars, ie. systematic battles between the inhabitants of one anthill and the inhabitants of another, in which both sides are under the threat of mass extermination. It is only recently that scientists have begun to realize how closely ants' warfare mimics our own methods of warfare. It has been found that ants, just like humans, use a surprising number of different tactics, attack methods, and strategies in combat that determine when and where to start a battle.

Fear and awe

It is noteworthy that the methods of waging war in humans and ants are similar, despite the sharp differences in the biology and social structure of their communities. The population of anthills mainly consists of sterile females playing the role of workers or soldiers (at times they are joined by several short-lived male drones) of iodine or several fertile females. Community members do not have a centralized management, a clear leader, notions of power and hierarchy. Despite the fact that the queens act as the centers of the colony's life (since they ensure its reproduction), they do not lead the shelves and do not organize work. We can say that the colonies are decentralized, and the workers, each of which individually has a minimum of information, make their own decisions in the fight, which, nevertheless, turn out to be effective, despite the lack of centralization in the group; this is known as swarm intelligence. But although insects and humans lead different lifestyles, they fight their brethren for similar reasons. We are talking about economic and territorial factors, conflicts associated with finding a convenient shelter or food source, and sometimes even with labor resources: some species of ants abduct larvae from other anthills in order to raise slaves from them.

- Some ant species live in tightly knit colonies, numbering from thousands to millions, which from time to time go to war with other anthills, trying to reclaim additional resources, such as territory or food sources.

The tactics used by ants in war depend on what is at stake. Some species win in battle due to a constant offensive, which is why a statement from the treatise * 0 on the art of war * of the great Chinese military leader Sun Tzu comes to mind, who back in the VI century. BC wrote: - War loves victory and does not like duration. In nomadic ants, various species of which inhabit warm regions around the world and in some other representatives, for example, Asian marauder ants, hundreds or even millions of individuals act in closed phalanxes blindly, attacking prey and enemies as soon as they appear in front of them. In Ghana, I saw a living carpet of working ants of the nomadic species Dorytus nigricans, lined up shoulder to shoulder in an army and moving through the terrain, and their column was about 30 m wide. These African warlike ants, which in the case of species like D. Nigricans move in wide columns and therefore they are called nomadic, with their blade-like jaws they easily cut off flesh and can finish off a victim thousands of times larger than themselves. Although vertebrates can usually avoid encountering ants, in Gabon I saw an antelope trapped and eaten alive by an army of stray ants. Both groups of ants are marauders. and nomads use other competing ants for food, and with such a large number of armies, victory over any rival, which can then be eaten, is inevitable. Nomadic ants almost always hunt with the whole mass, and their choice of prey is very disgusting - they systematically storm anthills of other colonies in order to eat their brood (i.e. larvae and eggs).

Moving phalanxes of nomads or marauders are reminiscent of the military units that formed people both in the American Civil War and in the times of the ancient Sumerian states. Moving in the form of such columns in the absence of a specific end goal turns each of their raids into a gamble: insects can head towards the barren territory and not find enough food there.

Other ant species send smaller groups of workers called scouts in search of food. Thanks to the fan-shaped distribution, the small number of scouts cover a wider territory, encountering much more prey and enemies, while the rest of the colony is in the nest area.

However, communities that rely on scouts can generally catch much less prey because of the encounter with it. the scouts must have time to return to the anthill and carry away the main forces with them - usually by releasing pheromone chemicals. prompting the army to follow them. During the time it takes for the scouts to connect with the main forces, the enemy can regroup or retreat. In the case of nomadic or marauding ants, on the other hand, workers can immediately turn to their comrades for help due to the fact that they move behind them.

Placing troops

Columns of marauders and nomads are so dangerous and successful not only because of their high numbers. My research on marauding ants has shown that their armies are redeployed in a certain way, which makes them very effective and thus reduces the risk to the colony. The actions of individual individuals depend on their magnitude. Marauder workers vary in size, and this difference is much more pronounced than in any other species. Tiny individuals of small worker ants (in my conventional classification - "infantry") quickly move in the vanguard - in the danger zone, where the first clash of the army with opposing colonies of ants or other prey occurs. By themselves, small working individuals have no chance of defeating the enemy, if it is not a scout ant of the same size for single hunting species. However, a large number of such insects, marching in the front ranks of the army, will create a serious obstacle. While some of them can die in combat, they nevertheless manage to slow or immobilize the enemy until the moment when reinforcements in the form of larger workers of the working caste, known as medium and large worker ants, arrive, which will deal a fatal blow to the victim. Such individuals are present in the army in smaller numbers, but they are much more dangerous, since some of them are about 500 times heavier than small ants.

The sacrifice of small workers on the front line helps to reduce mortality among medium and large soldiers, for the feeding and preservation of which the colony requires much more resources. Pushing the most easily replaceable fighters into the zone of greatest risk is an old and time-tested tactic. The ancient inhabitants of Mesopotamia acted in a similar way with a slightly recoverable and lightly armed militia from the peasants, which was herded into a kind of herd, and the worst weight that a war could bring down fell upon it. At the same time, the elite part of the army (of wealthy citizens) had the most valuable weapons, including protective ones, which allowed it to remain relatively safe under the protection of these crowds during the battle. How human armies can defeat the enemy, exhausting him. wounding over and over again and finishing off the entire army by attack (tactics of "defeat in parts"), so the marauder ants mow down opponents quickly enough, moving forward with the whole army and exhausting them, instead of trying to simultaneously resist the enemy power.

In addition to destroying representatives of other species of ants and other prey, marauding ants actively protect the territories around anthills and hunting grounds from the invasion of other armies of their kind. Medium and large ants usually stay behind until each small soldier grabs the limbs of the enemy. Clashes like these can last for several hours are shown to be more disastrous than the battles that occur between marauders and representatives of other species. Hundreds of tiny ants interlock over an area of several square meters, gradually tearing each other to pieces.

This variant of hand-to-hand combat is the most common form of destruction of the enemy for ants. The mortality rate among members of a large colony is almost invariably high and is directly related to the low value of the life of individual individuals. Ants, which are less able to withstand a strong foe in a direct collision, resort to using weapons with a larger radius of action, allowing them to injure or immobilize the enemy without approaching him. - for example, stun an opponent with something like tear gas, as do the red forest ants of the genus Formica, which live in Europe and North America, or throw small stones at his head, which is typical for the Dorymyrmex bieolar ants from Arizona.

A study by Nigel Franks of the University of Bristol in England showed that the attack mode practiced among nomadic ants and marauders is organized according to Lanchester's Quadratic Law, one of the equations developed during World War I by engineer Frederick Lanchester (Frederick Lanchester) to assess the potential strategies and tactics of opposing sides. His mathematical calculations showed that when there are many simultaneous fights in a certain territory, the superiority in numbers gives more advantages than the higher qualities of individual fighters. Therefore, it is only when the danger grows, reaching extreme levels, that larger individuals of marauding ants enter the battle, putting themselves at risk.

So, due to the fact that Lancheether's quadratic law does not apply to all cases of battles between humans, it also does not describe all situations in battles between insects. The group of slave ants (also called the Amazon ants) is one such surprising exception. Certain individuals of the Amazons steal brood from the colony they attacked in order to raise slaves from it in their anthill. Durable Amazon armor (exoskeleton) and knife-like jaws provide them with superpowers in battle. Therefore, they are not afraid to attack the anthill, the defenders of which greatly outnumber them. To avoid death, some Amazon ants use "chemical propaganda" - they emit chemical signals that cause disorientation in the attacked colony and keep the working ants of the injured side from attacking the aggressors. By doing so, as Frank and his undergraduate student Lucas Partridge of the University of Bath have shown, they change the mode of the fight, so that the outcome is determined by a different Lanchester equation. which describes the battles of people in a certain historical period. This is the so-called linear Lanchester's law. showing the fight. in which the rivals fight one on one (which the Amazons achieve by releasing a chemical signaling substance) and the victory goes to the side whose warriors are stronger, even if their opponent has a significant numerical superiority. In fact, a colony surrounded by slave ants allows attackers to plunder the anthill with little or no resistance.

Among ants, the combat value of each individual for the colony as a whole is associated with the risk to which it is ready to take in battle: the higher it is, the more likely that the insect will die from the damage received, but also cause maximum damage to the enemy. For example, the guards that surround the foraging trails of marauding ants are made up of older female workers, injured in labor, who usually fight to the last. In a 2008 article for Naturwissenschaften, Deby Cassill of the University of South Florida wrote that only older (one-month old) fire ants participate in skirmishes, while week-old workers attacked flee, and diurnal ones fall and lie motionless. pretending to be dead. Then the usual practice for a person to mobilize healthy young people for military service, when viewed from the standpoint of ants, may seem pointless. But anthropologists have found some evidence that indicates that, in at least a few cultures, successful warriors have always had more descendants. Subsequent reproductive success could make combat worth such a risk - a factor not applicable to worker ants due to their sterility.

Territory control

Other ant war strategies, analogous to those in humans, have become known from the observation of Asian tailor ants. These insects inhabit the canopy of most of the tropical forests of Africa, Asia and Australia, where they can build giant nests located on several trees at once, and their colonies number up to 500 thousand individuals, which is comparable to the number of large settlements of some nomadic ants. Tailors resemble nomadic ants and are highly aggressive. Despite these similarities, the two species use completely different working methods. While nomadic ants do not defend the territory, since in their campaigns for prey (ants of other species that they feed on) they all move together, colonies of tailor ants populate and fiercely defend a certain area, sending their workers in different directions, who follow for the penetration of opponents deep into this zone. They skillfully control what is happening in a huge space in the crowns of trees, protecting several key points, for example, the lower part of the tree trunk, bordering the ground. Suspended nests made of leaves are located at strategic points in the crowns, and troops of fighters step out of them where they are needed.

Working tailor ants are also more independent than nomads. The constant raids of nomadic ants contributed to limiting their autonomy. Due to the fact that the orders of these insects exist in a continuously moving column, they need a relatively small amount of communication signals. Their reactions to the appearance of enemies or victims are highly regimented. Tailoring ants, on the other hand, roam their territory more freely and are less constrained in their reactions to new dangers or opportunities for profit. Differences in lifestyles evoke contrasting pictures of the formation of the army of Frederick the Great and the more mobile columns of Napoleon on the battlefield.

Tailoring ants follow a strategy similar to that of nomad ants when capturing prey and destroying enemies. In all cases, tailor ants use a short-range, attractive pheromone synthesized by their mammary glands, which prompts nearby brethren to fight. Other elements of the "official protocol" of tailor ants are specific to the period of hostilities. When a worker returns from a fight with another colony, he sharply bends his body at the sight of fellows passing by in order to warn them of an ongoing fight. At the same time, along the entire route, it secretes another chemical secretion produced by the rectal gland. It contains a pheromone that encourages all members of the colony to follow this ant to the battlefield. Moreover, to claim a previously unoccupied space, workers use another signal, namely to defecate at specific points, much like dogs marking their territory with urine tags.

Size matters

In both cases, in both ants and humans, the urge to engage in actual combat is directly related to the size of the community. Small colonies rarely organize protracted battles - except in cases of self-defense. Just as hunter-gatherer tribes, which were often nomadic and lacking large stocks, tiny ant colonies of only a few dozen individuals do not create a fixed network of trails, pantries, or nests to die for. In times of intense conflict between the two groups, such ants, like tribes of humans with similar lifestyles, would rather flee than fight.

Sprawling colonies usually already accumulate a certain amount of resources that would be worth protecting, but their numbers are still not large enough to risk the lives of their troops. Medium-sized colonies of honey ants from the southwestern United States are an example of a community that avoids unnecessary fights. In order to calmly hunt the living creatures living in the vicinity of the anthill, they can start preventive skirmishes near the neighboring anthill so that the enemy is distracted and does not arrange fights that are dangerous for the existence of the colony. During such distracting skirmishes, rival ants rise high on their six legs and walk around each other in circles. This ritualized behavior is more of a bloodless, ceremonial display of power that is common to small clans of people, as suggested by biologists Bert Holldobler of Arizona State University and Edward Osborne Wilson of Harvard. With a fortunate coincidence, a community with fewer tournament ants - which is typical of weaker colonies - can retreat without loss, while a victorious side, capable of causing serious damage to its enemies, is able to eat the brood and kidnap large workers who act as "containers "Swollen from food, which they regurgitate in response to the requests of other members of the nest. Honey ant winners transport the fattening workers to their nest and keep them as slaves. To avoid such a fate, worker scout ants inspect the venues of demonstration tournaments, trying to determine when the rival side begins to outnumber them, and, if necessary, take flight.

Participation in serious battles is most typical for ant species that live in large colonies, consisting of hundreds of thousands of individuals or more. Scientists are inclined to believe that such giant clusters of social insects are not very effective, because produce fewer new queens and males per capita than smaller groups. On the contrary, I consider them to be very productive, since they have the opportunity to invest resources not only in reproduction, but also in labor. which would exceed the required minimum; it is similar to the work of the human body, producing adipose tissue, which can fuel the body during difficult times. Various researchers argue that individual ant individuals do less and less useful work as the community grows, and this leads to the fact that most of the colony exhibits minimal activity at the same time. In this regard, the increase in the size of the community will increase the share of the reserve intended for the army, which will allow the Lanceether's law to be put into effect in clashes with enemies. By analogy, most anthropologists believe that people began to get involved in full-scale wars only after the size of their communities increased dramatically, which was associated with the transition to agriculture.

Superorganisms and supercolonies

The ability for extreme forms of warfare appeared in ants due to their social association, which is similar to the union of individual cells into a single organism. Cells recognize each other by the presence of certain chemical signals on their surface membranes: a healthy immune system attacks any cell with different identifying marks. In most healthy colonies of ants, the same principle works: they recognize their own by a specific smell coming from them, and they attack or avoid those whose smell is different from the inhabitants of their anthill. For ants, this scent is like the national flag tattooed on their skin. The persistence of the scent ensures that for the ants, the war cannot end in a relatively bloodless victory of one colony over another. Insects cannot “change citizenship” (at least adults). There may be a small number of rare exceptions, but in the vast majority of cases, every worker ant in the colony will be part of its native community until death. (The interests of an individual ant and the whole colony do not always coincide. Working ants of some species may try to start reproduction - but they are unlikely to be able - mainly due to a conflict in the work of different genes of their body.) Such a rigid attachment to their colony is present in all ants. because their communities are anonymous, i.e.each worker ant recognizes the belonging of a particular individual to a particular caste, for example, soldiers or queens, but is not capable of individual recognition of individuals within a community. Absolute loyalty to one's community is a fundamental property of all creatures acting as separate elements of a single superorganism, in which the death of one worker ant causes much less damage than, for example, the loss of one finger from a person. And the larger the colony, the less sensitive such a "cut" will be.

The most impressive example of insect devotion to their nest is the Argentine ants, or Linepithema humile. These indigenous inhabitants of Argentina quickly spread throughout the world as a result of human activities. The largest supercolony is in California, stretching along the coast from San Francisco to the Mexican border, and perhaps has a trillion individuals, united by a trait of "national" commonality. Every month, millions of Argentine ants are killed in the border battles that rage around San Diego, where the supercolony's territory touches those of three other communities. The war lasts from the moment insects appeared on the territory of the state, i.e. for about 100 years.

Lanchester's quadratic law can be successfully applied to describe these fights. Argentine ants, "cheap to produce" - tiny and, as they are exterminated, are constantly replaced by new warriors thanks to inexhaustible reinforcements, form colonies with a population density of up to several million individuals per one average suburban area with a house. These supercolonies, significantly outnumbering the enemy, no matter what local species try to resist them, police control the captured territories and kill every rival. which they face.

What gives the Argentine ant a constant willingness to fight? Many species of ants, as well as other animals, including humans, exhibit the “dead enemy effect,” as a result of which, after a period of conflict, as both opponents stop at the border, their mortality rate drops sharply. At the same time, the number of skirmishes decreases, and often empty * unoccupied * lands remain between them. However, in the river floodplains, where this species of ants comes from, the belligerent colonies must stop fighting every time. when water rises in the channel, driving them out on a hill. Therefore, the conflict never subsides, and the battle never ends. Thus, their wars continue without losing tension, decade after decade.

The violent invasion of supercolonies of ants is reminiscent of how human colonial superpowers once exterminated smaller tribes of local people, from American Indians to Australian Aborigines. But. Fortunately, humans do not form the superorganisms characteristic of insects: our belonging to a particular social group can change, allowing immigrants to join a new collective, thanks to which nations are gradually transforming. And if a war between ants, alas, may be inevitable, then people may well learn to avoid such a confrontation.

Translation: T. Mitina