War in ants

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Wars or conflicts can break out between different groups in some ant species for a variety of reasons. These violent confrontations typically involve entire colonies, sometimes allied with each other, and can end in a stalemate, the complete destruction of one of the belligerents, the migration of one of the groups, or, in some cases, the establishment of cordial relations between the different combatants or the adoption of members of the losing group. For some species of ants, this is even a deliberately undertaken strategy, as they require capturing pupae from other species to ensure the continuity of their colony. Thus, there are specific biological evolutions in certain species intended to give them an advantage in such conflicts. In some of these confrontations, ants can adopt ritualized behavior, even governed by certain implicit rules, for example by organizing duels between the most important ants of each colony or choosing a specific location for a battle.

Contents

These conflicts are not simply internal to ants, which can fight each other even within the same species, but also involve other animals, particularly other eusocial insects like termites or wasps. In the early 21st century, with the rapid spread of many species into new habitats facilitated by human colonization, significant wars are being waged between different supercolonies.

Terminology

The use of the term "war", found in scientific literature, [1] [2] [3] is an anthropocentric analogy, derived from human wars.

Causes and prevalence

Causes

The reasons that can lead ant colonies to clash are varied and depend on the species, locations, and contexts. For a number of them, such as leafcutter ants Atta laevigata , wood ants of the genus Formica, certain species of the genus Carebara , or giant ants Dinomyrmex gigas, it is a matter of territory covered and thus the available food for the different colonies. [2] [3] [4] [5] It can also be related to issues of overpopulation of the same species in the same area at certain times of the year. [3] In other cases, some species aim to capture the pupae of an opposing group to use them in their own colony later. [1]

Prevalence

It is difficult to assess the prevalence of this type of behavior in ants, given the significant diversity of species, behaviors, and different situations. Some species undergo specific evolutions with the sole purpose of engaging in these conflicts, such as Polyergus rufescens, which have sickle-shaped mandibles. [6] The emergence of supercolonies from the 19th century, facilitated by human movements, has certainly reinforced these behaviors in the affected ants. [7] It also seems to depend on the context in which the ants find themselves. [7] For instance, within the same species, a colony facing external threats from another ant colony can produce up to twice as many soldier larvae as a colony not experiencing the same pressures. [7] Some species are almost exclusively on defensive strategies, such as Camponotus ligniperdus, which are peaceful and occupy a small territory but defend it fiercely against any incursion, even against more dangerous or deadly species. [8]

Process and outcomes

Process

In general, there are two main ways ants conduct these conflicts. [9] On the one hand, some species use specific ants that are more powerful and whose primary function is to fight. [9] On the other hand, colonies increase the number of available fighters and send large numbers of individuals into battle. [9] [10] In some species, conflict is ritualized, for example through limited duels undertaken by the individuals most capable of combat, [2] but phenomena of battles are also common. [3] [10] In the genus Formica , such battles are commonplace and can involve tens of thousands of individuals, and they are sometimes ritualized, with the respective groups withdrawing at nightfall only to return the next day to the same locations to resume the battle. [3] The bodies of dead or injured ants are then brought back to the colony, where they are eaten. [3] In other species, such as within the genus Carebara , ants arrange themselves in specific formations before the battle, like phalanxes, and advance against each other. [5] They also regularly sacrifice workers, whose role is to try to hinder, injure, and attack enemy majors, before their own majors join the battlefield and can intervene. [5]

In other cases, particularly among ants that aim to capture larvae or pupae, colonies use chemical weapons, such as olfactory propaganda, to try to enter the targeted colonies as discreetly as possible. [5]

Outcomes

Generally, wars between ants are costly for the groups, which must allocate a significant portion of their production to the war effort, to the detriment of forming workers, for example. [7] These wars can result in the death of tens of thousands of individuals within a few hours; for wood ants of the genus Formica, there are regularly 10,000 casualties per day during the spring. [3] For these ants, the war ends either when the opposing colony is destroyed or when the available prey is sufficient again for the needs of the colonies, which have then lost thousands of members. [3] Estimates from 2016 on certain ant species show a loss of about a third of the total colony population in case of victory. [11]

For some species, such as Crematogaster mimosae, victory over an opposing colony usually results in the flight or death of the opposing queen, but the victorious colony often adopts the surviving ants of the losing colony, likely a way to avoid and mitigate the significant resource loss due to the war effort. [11] In a few rare cases, the queen of the losing colony is herself adopted by the victorious colony, and the two merge. [11]

Supercolonies

With the development of ant supercolonies, which follows human expansion into new areas, groups of dozens, hundreds, or even thousands of colonies [12] engage in large-scale conflicts against other species. [7] For example, around San Diego in the 2010s, millions of ants died each month in significant battles between the supercolony formed by Argentine ants and three other supercolonies present in the area. [5]

Related Research Articles

<span class="mw-page-title-main">Ant</span> Family of insects

Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.

<i>Formica exsecta</i> Species of ant

Formica exsecta is a species of ant found from Western Europe to Asia.

<i>Formica</i> Genus of ants

Formica is a genus of ants of the family Formicidae, including species commonly known as wood ants, mound ants, thatching ants, and field ants. Formica is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus Formica is the European red wood ant Formica rufa. Ants of this genus tend to be between 4 and 8 mm long. Ants belonging to the Formica genus possess a single knob or bump located between their thorax and abdomen. These ants primarily feed on honeydew, a sugary liquid produced by aphids. Formica ants appear to take on a shepherding role with smaller aphids, relocating them to different parts of plants to ensure a continuous food source for the aphids. By doing so, the ants can establish a relatively sustainable honeydew supply for both themselves and their colony.

<i>Formica cunicularia</i> Species of ant

Formica cunicularia is a species of ant found all over Europe. They are especially common in western Europe and southern England, but they can be found from southern Scandinavia to northern Africa and from Portugal to the Urals. In England, Donisthorpe records the species as having occurred as far north as Bewdley in Worcestershire. In Formica cunicularia, the worker is an ashy grey black color and is usually 4.0–6.5 mm long. The males are found to have a uniformly dark body and are 8.0–9.0 mm long. The queen is yellowish red to dark black and is 7.5–9.0 mm.

<span class="mw-page-title-main">Ant colony</span> Underground lair where ants live, eat, and tend eggs

An ant colony is a population of ants, typically from a single species, capable of maintaining their complete lifecycle. Ant colonies are eusocial, communal, and efficiently organized and are very much like those found in other social Hymenoptera, though the various groups of these developed sociality independently through convergent evolution. The typical colony consists of one or more egg-laying queens, numerous sterile females and, seasonally, many winged sexual males and females. In order to establish new colonies, ants undertake flights that occur at species-characteristic times of the day. Swarms of the winged sexuals depart the nest in search of other nests. The males die shortly thereafter, along with most of the females. A small percentage of the females survive to initiate new nests.

<span class="mw-page-title-main">Carpenter ant</span> Genus of ants (Camponotus spp.)

Carpenter ants are large ants indigenous to many forested parts of the world.

<span class="mw-page-title-main">Banded sugar ant</span> Species of carpenter ant (Camponotus consobrinus)

The banded sugar ant, also known as the sugar ant, is a species of ant native to Australia. A member of the genus Camponotus in the subfamily Formicinae, it was described by German entomologist Wilhelm Ferdinand Erichson in 1842. Its common name refers to the ant's liking for sugar and sweet food, as well as the distinctive orange-brown band that wraps around its gaster.

<i>Formica polyctena</i> Species of ant

Formica polyctena is a species of European red wood ant in the genus Formica and large family Formicidae. The species was first described by Arnold Förster in 1850. The latin species name polyctena is from Greek and literally means 'many cattle', referring to the species' habit of farming aphids for honeydew food. It is found in many European countries. It is a eusocial species, that has a distinct caste system of sterile workers and a very small reproductive caste. The ants have a genetic based cue that allow them to identify which other ants are members of their nest and which are foreign individuals. When facing these types of foreign invaders the F. polyctena has a system to activate an alarm. It can release pheromones which can trigger an alarm response in other nearby ants.

<i>Harpagoxenus sublaevis</i> Species of ant

Harpagoxenus sublaevis is a species of ant in the subfamily Myrmicinae. It is found in Austria, France, Germany, Italy, and Switzerland.

<i>Formica sanguinea</i> Species of ant

Formica sanguinea, or blood-red ant, is a species of facultative slave-maker ant in the genus Formica characterized by the ability to secrete formic acid. It ranges from Central and Northern Europe through Russia to Japan, China, the Korean Peninsula, Africa and also the United States. This species is coloured red and black with workers up to 7 mm long.

<span class="mw-page-title-main">Argentine ant</span> Species of ant

The Argentine ant is an ant native to northern Argentina, Uruguay, Paraguay, Bolivia and southern Brazil. This invasive species was inadvertently introduced by humans on a global scale and has become established in many Mediterranean climate areas, including South Africa, New Zealand, Japan, Easter Island, Australia, the Azores, Europe, Hawaii, and the continental United States. Argentine ants are significant pests within agricultural and urban settings, and are documented to cause substantial harm to communities of native arthropods, vertebrates, and plants within their invaded range.

<i>Polyrhachis</i> Genus of ants

Polyrhachis is a genus of formicine ants found in the Old World with over 600 species. The genus is yet to be comprehensively resolved and contains many varied species including nest-weavers, swimming workers, soil and tree-dwellers. First fossil record of this genus was P. annosa from Miocene.

<i>Formica truncorum</i> Species of ant

Formica truncorum is a species of wood ant from the genus Formica. It is distributed across a variety of locations worldwide, including central Europe and Japan. Workers can range from 3.5 to 9.0mm and are uniquely characterized by small hairs covering their entire bodies. Like all other ants, F. truncorum is eusocial and demonstrates many cooperative behaviors that are unique to its order. Colonies are either monogynous, with one queen, or polygynous, with many queens, and these two types of colonies differ in many characteristics.

<span class="mw-page-title-main">Slave-making ant</span> Species of ants that steal young ants of another species to contribute to their colony

Slave-making ants or slaver ants are brood parasites that capture broods of other ant species to increase the worker force of their colony. After emerging in the slave-maker nest, slave workers work as if they were in their own colony, while parasite workers only concentrate on replenishing the labor force from neighboring host nests, a process called slave raiding.

<i>Polyergus rufescens</i> Species of ant

Polyergus rufescens is a species of slave-making ant native to southern Europe and parts of Asia, commonly referred to as the European Amazon ant or as the slave-making ant. It is an obligatory social parasite, unable to feed itself or look after the colony and reliant on ants of another species to undertake these tasks. To replenish these servant ants, it raids nearby ant colonies and carries home pupae and larvae, and these are reared to provide future workers for the colony. A newly mated female P. rufescens needs to make its way into one of these "host" nests, kill the host queen, and be accepted by the host workers in her place.

<i>Camponotus floridanus</i> Species of ant known as the Florida carpenter ant

Camponotus floridanus, or Florida carpenter ant, is a species of ant in the genus Camponotus. First described as Formica floridana by Buckley in 1866, the species was moved to Camponotus by Mayr in 1886. The ant is widespread in Florida and occurs as far north as North Carolina and as far west as Mississippi.

<i>Camponotus castaneus</i> Species of ant

Camponotus castaneus, the red hazelnut carpenter ant, is a species of carpenter ant located in the eastern United States. It is a primarily orangish-red ant in the family Camponotus. Its workers are usually around 8-10 mm, and queens around 18-20 mm. As with most Camponotus species, camponotus castaneus has majors and super-majors, usually appearing in the second or third year of the colony's founding, majors are usually 10-14 mm, with super majors being around 13-17 mm. Camponotus castaneus has a generalist diet, feeding on insects and carbohydrates such as honeydew, which is easily accessible. The ant has a smooth thorax and abdomen, with 1 node separating them.

<i>Camponotus ligniperda</i> Brown-black carpenter ant

Camponotus ligniperda, the brown-black carpenter ant, is a common species of carpenter ant distributed widely throughout Europe. Found in a variety of woodland habitats, they commonly nest on the ground in dry tree stumps, dead fallen trees, or beneath stones and wooden logs that are partially buried. C. ligniperda is an ecologically dominant species wherever it is found due to both its large size and particularly aggressive nature.

In ants, social conflicts, sex conflicts, or caste conflicts can exist. These conflicts occur within the same colony or supercolony at various levels: on an individual scale, between two or more specific ants; on the scale of sex, between males and females; or on the scale of different castes, between queens and workers. They should not be confused with ant wars, which involve different and opposing colonies or supercolonies. Even as larvae, ants can engage in conflicts, typically at the scale of the entire colony, against other individuals within the same colony. These social conflicts may involve the male-to-female ratio within the colony. For example, in some species, male and female larvae may engage in mutual cannibalism, often with males being more aggressive, to increase their chances of survival and growth. Conflicts can also arise between workers and queens over the management of the larvae produced; workers may favor female larvae, while queens increase the ratio of males they lay. These conflicts are generally more intense depending on the degree of relatedness between the ants involved. For instance, ants belonging to the same supercolony or a polygynous colony - meaning a colony with several queens - tend to engage more against workers or larvae from a queen different from their own. In species and colonies operating under the gamergate system, where each worker is a potential queen, ants engage in battles to become the sole or one of the few worker-queens capable of laying eggs.

References

  1. 1 2 Chauvin, Rémy (1974). "Les sociétés les plus complexes chez les insectes". Communications. 22 (1): 63–71. doi:10.3406/comm.1974.1338. Archived from the original on 9 March 2024. Retrieved 8 July 2024.
  2. 1 2 3 Pfeiffer, Martin; Linsenmair, Karl Eduard (1 December 2001). "Territoriality in the Malaysian giant ant Camponotus gigas (Hymenoptera/Formicidae)". Journal of Ethology. 19 (2): 75–85. doi:10.1007/s101640170002. ISSN   1439-5444.
  3. 1 2 3 4 5 6 7 8 Mabelis, A. A. (1 January 1983). "Interference Between Wood Ants and Other Ant Species (Hymenoptera, Formicidae)". Netherlands Journal of Zoology. 34 (1): 1–20. doi:10.1163/002829684X00010. ISSN   1568-542X. Archived from the original on 8 March 2021. Retrieved 8 July 2024.
  4. ↑ WHITEHOUSE, MARY E.A.; JAFFE, KLAUS (June 1996). "Ant wars: combat strategies, territory and nest defence in the leaf-cutting antAtta laevigata". Animal Behaviour. 51 (6): 1207–1217. doi:10.1006/anbe.1996.0126. ISSN   0003-3472. Archived from the original on 8 July 2024. Retrieved 8 July 2024.
  5. 1 2 3 4 5 Moffett, Mark W. (2011). "Ants & the Art of War". Scientific American. 305 (6): 84–89. Bibcode:2011SciAm.305e..84M. doi:10.1038/scientificamerican1211-84 (inactive 8 July 2024). ISSN   0036-8733. JSTOR   26002920. PMID   22214134.{{cite journal}}: CS1 maint: DOI inactive as of July 2024 (link)
  6. ↑ Laurent Cournault. Les fourmis : une biodiversité méconnue (PDF). p. 6. Archived (PDF) from the original on 8 July 2024. Retrieved 8 July 2024.
  7. 1 2 3 4 5 Keller, Laurent; Gordon, Élisabeth (2013). La vie des fourmis. Poches. Paris: O. Jacob. ISBN   978-2-7381-2968-0.
  8. ↑ Czechowski, Wojciech (1 January 1988). "Inter- and intraspecific competive relations in Camponotus ligniperdus (Latr.) (Hymenoptera, Formicidae" (PDF). Annales Zoologici. Retrieved 8 July 2024.
  9. 1 2 3 Lymbery, Samuel J.; Webber, Bruce L.; Didham, Raphael K. (12 September 2023). "Complex battlefields favor strong soldiers over large armies in social animal warfare". Proceedings of the National Academy of Sciences. 120 (37): e2217973120. Bibcode:2023PNAS..12017973L. doi:10.1073/pnas.2217973120. ISSN   0027-8424. PMC   10500280 . PMID   37639613.
  10. 1 2 CSIRO. "Ant wars: How native species can win the battle over invasive pests". phys.org. Archived from the original on 29 August 2023. Retrieved 8 July 2024.
  11. 1 2 3 Rudolph, Kathleen P.; McEntee, Jay P. (17 December 2015). "Spoils of war and peace: enemy adoption and queen-right colony fusion follow costly intraspecific conflict in acacia ants". Behavioral Ecology. 27 (3): 793–802. doi:10.1093/beheco/arv219. ISSN   1045-2249. Archived from the original on 8 July 2024. Retrieved 8 July 2024.
  12. ↑ Moffett, Mark W. (2012). "Supercolonies of billions in an invasive ant: What is a society?". Behavioral Ecology. 23 (5): 925–933. doi:10.1093/beheco/ars043. ISSN   1465-7279. Archived from the original on 24 August 2023. Retrieved 8 July 2024.
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