Dorylus

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Dorylus
Dorylus gribodoi casent0172627 dorsal 1.jpg
Dorylus gribodoi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Leach, 1815
Subfamily: Dorylinae
Leach, 1815
Genus: Dorylus
Fabricius, 1793
Type species
Vespa helvola
Diversity [1]
61 species
Synonyms

CosmaecetesSpinola, 1851
Shuckardia Emery, 1895
SphecomyrmexSchulz, 1906
SphegomyrmexImhoff, 1852

Contents

Dorylus, also known as driver ants, safari ants, or siafu, is a large genus of army ants found primarily in central and east Africa, although the range also extends to southern Africa and tropical Asia. The term siafu is a loanword from Swahili, [2] and is one of numerous similar words from regional Bantu languages used by indigenous peoples to describe various species of these ants. Unlike the New World members of the former subfamily Ecitoninae (now Dorylinae), members of this genus form temporary subterranean bivouacs in underground cavities which they excavate and inhabit - either for a few days or up to three months. Also unlike some New World army ants, driver ants are not specialized predators of other species of ant, instead being more generalistic with a diet consisting of a diversity of arthropods. Colonies are enormous compared to other army ants and can contain over 20 million individuals. As with their American counterparts, workers exhibit caste polymorphism with the soldiers having particularly large heads that power their scissor-like mandibles. They are capable of stinging, but very rarely do so, relying instead on their powerful shearing jaws. [3] Driver ant queens are the largest living ants known, with the largest measuring between 40 - 63 millimeters (1.5 - 2.4 inches) in total body length depending on their physiological condition. [4]

Life cycle

Some soldier safari ants make tunnels to provide a safe route for the workers. Safari ants tunnel.jpg
Some soldier safari ants make tunnels to provide a safe route for the workers.

Seasonally, when food supplies become short, they leave the hill and form marching columns of up to 50,000,000 ants, which are considered a menace to people, though they can be easily avoided; a column can only travel about 20 metres in an hour. It is for those unable to move, or when the columns pass through homes, that there is the greatest risk. [5] Their presence is, conversely, beneficial to certain human communities, such as the Maasai. They perform a pest prevention service in farming communities, consuming the majority of other crop-pests, from insects to large rats. [6] For example, driver ants prey on larvae of the African sugarcane borer, a pest moth in sub-Saharan Africa.

The characteristic long columns of ants will fiercely defend themselves against anything that attacks them. [3] Columns are arranged with the smaller ants being flanked by the larger soldier ants. These instinctively take up positions as sentries, and set a perimeter corridor through which the smaller ants can run safely. Their bite is severely painful, each soldier leaving two puncture wounds when removed. Removal is difficult, however, as their jaws are extremely strong, and one can pull a soldier ant in two without it releasing its hold. Large numbers of ants can kill small or immobilized animals and strip them to husks. A large part of their diet is earthworms. All Dorylus species are blind, and, like most varieties of ants, communicate primarily through pheromones. [3]

In the mating season, alates (winged drones, queens of driver-ant species do not grow wings) are formed. The drones are larger than the soldiers and the queens are even larger. Driver ants do not perform a nuptial flight, but mate on the ground and the queens go off to establish new colonies. As with most ants, workers and soldiers are sterile females, and so do not reproduce. [3]

A male driver ant Dorylus helvolus, l, Seringveld.jpg
A male driver ant

Male driver ants, sometimes known as "sausage flies" (a term also applied to males of New World dorylines) due to their bloated, sausage-like abdomens, are among the largest ant morphs and were originally believed to be members of a different species. Males leave the colony soon after hatching but are drawn to the scent trail left by a column of siafu once they reach sexual maturity. When a colony of driver ants encounters a male, they tear his wings off and carry him back to the nest to be mated with a recently hatched queen. As in the majority of ant species, males die shortly afterward. [3] Driver ant queens exhibit polyandry; young queens from some species with large colony sizes must mate with 10–20 males before they have gathered enough sperm for their reproductive lives. [7] Once the queen is ready, roughly half of the workers in the colony will leave with her to found a new colony. [8] Driver ant queens are the largest ants on Earth and have the greatest egg-laying capacity among insects, laying several million eggs each month. [9]

Such is the strength of the ant's jaws that, in East Africa, they are used as natural emergency sutures. Various East African indigenous tribal peoples (e.g. Maasai moran), when suffering from a gash in the bush, will use the soldiers to stitch the wound by getting the ants to bite on both sides of the gash, then breaking off the body. This use of ants as makeshift surgical staples creates a seal that can hold for days at a time, and the procedure can be repeated, if necessary, allowing natural healing to commence. [10]

Several species in this genus carry out raids on termitaria, paralyzing or killing termites and carting them back to the nest. [11]

Colonies of driver-ant species have only one queen. [12] When she dies, the surviving workers may try to join another colony, but in other cases, when two colonies of the same driver-ant species meet, they usually change the marching directions to avoid conflicts.[ citation needed ]

Species

Dorylus sp. in Cameroon, consuming a grasshopper Dorylus.JPG
Dorylus sp. in Cameroon, consuming a grasshopper
Dorylus sp. in Zambia, consuming mayonnaise Dorylusmayonnaise.JPG
Dorylus sp. in Zambia, consuming mayonnaise
A column of safari ants in Kakamega Forest, Kenya, guarded by soldiers Safari Ants - Kakamega-Forest Kenya.jpg
A column of safari ants in Kakamega Forest, Kenya, guarded by soldiers

See also

Related Research Articles

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

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

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<span class="mw-page-title-main">Army ant</span> Name used for several ant species

The name army ant (or legionary ant or marabunta) is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limited area.

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<i>Eciton burchellii</i> Species of ant

Eciton burchellii is a species of New World army ant in the genus Eciton. This species performs expansive, organized swarm raids that give it the informal name, Eciton army ant. This species displays a high degree of worker polymorphism. Sterile workers are of four discrete size-castes: minors, medias, porters (sub-majors), and soldiers (majors). Soldiers have much larger heads and specialized mandibles for defense. In lieu of underground excavated nests, colonies of E. burchellii form temporary living nests known as bivouacs, which are composed of hanging live worker bodies and which can be disassembled and relocated during colony emigrations. Eciton burchellii colonies cycle between stationary phases and nomadic phases when the colony emigrates nightly. These alternating phases of emigration frequency are governed by coinciding brood developmental stages. Group foraging efforts known as "raids" are maintained by the use of pheromones, can be 200 metres (660 ft) long, and employ up to 200,000 ants. Workers are also adept at making living structures out of their own bodies to improve efficiency of moving as a group across the forest floor while foraging or emigrating. Workers can fill "potholes" in the foraging trail with their own bodies, and can also form living bridges. Numerous antbirds prey on the Eciton burchellii by using their raids as a source of food. In terms of geographical distribution, this species is found in the Amazon jungle and Central America.

<span class="mw-page-title-main">Nuptial flight</span> Mating flight of eusocial insects

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<i>Crematogaster</i> Genus of ants

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<i>Acromyrmex</i> Genus of ants

Acromyrmex is a genus of New World ants of the subfamily Myrmicinae. This genus is found in South America and parts of Central America and the Caribbean Islands, and contains 33 known species. Commonly known as "leafcutter ants" they comprise one of the two genera of advanced attines within the tribe Attini, along with Atta.

<span class="mw-page-title-main">Eusociality</span> Highest level of animal sociality a species can attain

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<i>Tetraponera</i> Genus of ants

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<i>Dorylus laevigatus</i> Species of ant

Dorylus laevigatus is a member of the army ant genus Dorylus, or Old World army ants. More specifically known as "driver ants", the genus Dorylus is abundant throughout Africa and stretches into tropical Asia, where D. laevigatus is primarily found. They are a eusocial colony-forming species, which live primarily underground, rarely venturing to the surface for any reason. D. laevigatus colonies are small for army ants, estimated averages falling between 30,000 and 1,000,000 individuals.

Dorylus molestus is a species of African army ant.

<i>Neivamyrmex</i> Genus of ants

Neivamyrmex is a genus of army ants in the subfamily Dorylinae.

<i>Dorylus gribodoi</i> Species of ant

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<span class="mw-page-title-main">Ergatoid</span> Wingless reproductive ant or termite

An ergatoid is a permanently wingless reproductive adult ant or termite. The similar but somewhat ambiguous term ergatogyne refers to any intermediate form between workers and standard gynes. Ergatoid queens are distinct from other ergatogyne individuals in that they are morphologically consistent within a species and are always capable of mating, whereas inter caste individuals, another class of ergatogynes, often are not. Ergatoids can exhibit wide morphological differences between species, sometimes appearing almost identical to normal workers and other times being quite distinct from both workers and standard queens. In addition to morphological features, ergatoids among different species can exhibit a wide range of behaviors, with some ergatoids acting only as reproductives and others actively foraging. Ergatoid queens have developed among a large number of ant species, and their presence within colonies can often provide clues on the social structures of colonies and as to how new colonies are founded. Without wings, almost all species of ants that solely produce ergatoid queens establish new colonies by fission.

<i>Megaponera</i> Genus of ants

Megaponera analis is the sole species of the genus Megaponera. They are a strictly termite-eating (termitophagous) ponerine ant species widely distributed in Sub-Saharan Africa and most commonly known for their column-like raiding formation when attacking termite feeding sites. Their sophisticated raiding behaviour gave them the common name Matabele ant after the Matabele tribe, fierce warriors who overwhelmed various other tribes during the 1800s. With some individuals reaching up to 25 millimetres (0.98 in) in length, M. analis is one of the world's largest ants.

This is a glossary of terms used in the descriptions of ants.

References

  1. Bolton, B. (2014). "Dorylus". AntCat. Retrieved 17 July 2014.
  2. Swahili translation Archived July 20, 2011, at the Wayback Machine
  3. 1 2 3 4 5 Hölldobler, Bert; Wilson, Edward O. (1990). The Ants . Belknap Press of Harvard University Press. ISBN   0-674-04075-9.
  4. Kronauer, Daniel (2020). Army Ants Nature's Ultimate Social Hunters. Cambridge, Massachusetts: Harvard University Press. p. 237. ISBN   978-0-674-24155-8.
  5. "NOVA - Master of the Killer Ants - PBS". www.pbs.org.
  6. Hastings, H.** Conling, D.E., Graham, D.Y.* & (1988-03-01). "Notes on the natural host surveys and laboratory rearing of Goniozus natalensis Gordh (Hymenoptera: Bethylidae), a parasitoid of Eldana saccharina Walker (Lepidoptera: Pyralidae) larvae from Cyperus papyrus L. in Southern Africa" [ permanent dead link ](PDF). Journal of the Entomological Society of Southern Africa
  7. Kronauer, Daniel J.C.; Johnson, Robert A.; Boomsma, Jacobus J. (February 23, 2007). "The Evolution of Multiple Mating in Army Ants". Evolution . 61 (2): 413–422. doi: 10.1111/j.1558-5646.2007.00040.x . PMID   17348950. The evolution of mating systems in eusocial Hymenoptera is constrained because females mate only during a brief period early in life, whereas inseminated queens and their stored sperm may live for decades…We show that queens of Neivamyrmex and Aenictus mate with the same high numbers of males (usually ca. 10–20) as do queens of army ant species with very large colony sizes…The species of Dorylus (Anomma) and Eciton where multiple queen mating has been documented (Kronauer 2004, 2006a, 2006b; Denny et al. 2004) have extreme degrees of worker caste polymorphism and larger colonies than almost any other social insect…
  8. Kronauer, Daniel J.C. (September 11, 2009). "Recent advances in army ant biology (Hymenoptera: Formicidae)". Myrmecological News . 12: 51–65. Retrieved 2023-07-05. The permanent lack of wings in army ant queens has one important corollary: they do not go on mating flights. Instead, young army ant queens mate inside their natal colony with foreign males that disperse on the wing…The reproductive colony undergoes fission during which the worker force splits into two roughly equal parts…
  9. Kronauer, Daniel J.C.; Johnson, Robert A.; Boomsma, Jacobus J. (February 23, 2007). "The Evolution of Multiple Mating in Army Ants". Evolution . 61 (2): 413–422. doi: 10.1111/j.1558-5646.2007.00040.x . PMID   17348950. Being the largest ants on Earth, African Dorylus (Anomma) queens also hold the world record in reproductive potential among the insects, with an egg-laying capacity of several millions per month…
  10. "From Ants to Staples: History and Ideas Concerning Suturing Techniques". ResearchGate.
  11. Biotropics Archived January 24, 2009, at the Wayback Machine
  12. Boswell, Grame P.; Franks, Nigel R.; Britton, Nicholas (19 March 2001). "Arms races and the evolution of big fierce societies" (PDF). Proceedings of the Royal Society B: Biological Sciences. 268 (1477): 1723–1730. doi:10.1098/rspb.2001.1671. PMC   1088800 . PMID   11506686 . Retrieved 2023-07-05. Here we consider the largest single-queen insect societies, those of the Old World army ant Dorylus, single colonies of which can have 20 million workers.