Megaponera

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Megaponera
Megaponera Major with termites, crop.jpg
A major worker with termite prey
Stridulating workers in a moving column
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Megaponera
Mayr, 1862
Species:
M. analis
Binomial name
Megaponera analis
(Latreille, 1802)
Megaponera Distribution Africa.png
Distribution
   Present in country
   Likely present in country
   Absent from country
Synonyms

Megaponera analis is the sole species of the genus Megaponera. [1] They are a strictly termite-eating (termitophagous) ponerine ant species widely distributed in Sub-Saharan Africa [2] 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. [3] With some individuals reaching up to 25 millimetres (0.98 in) in length, M. analis is one of the world's largest ants. [4] [5]

Contents

Taxonomy

Megaponera is a genus of ponerine ant first defined by Gustav Mayr in 1862 for Formica analis [6] (Latreille, 1802), the sole species belonging to the genus to date. In 1994 William L. Brown Jr. synonymised the genus under Pachycondyla even though he lacked phylogenetic justification, thereby changing the name from Megaponera foetens to Pachycondyla analis. [7] In 2014 Schmidt and Shattuck revived Megaponera back to full genus status due to both molecular and morphological evidence. Since foetens was just a specific epithet incorrectly used throughout the literature the new name for the species as of June 2014 is Megaponera analis. [1]

Subspecies of Megaponera analis

Due to its very wide distribution throughout Africa, it is likely that there are many more subspecies of M. analis than those recognised at the moment – some of which may warrant elevation to full species status.

The five currently recognised subspecies of M. analis are: [1]

Morphology

Pachycondyla analis sam-hym-c008323a profile 1.jpg
Minor worker
Pachycondyla analis sam-hym-c008323b profile 1.jpg
Major worker
Pachycondyla analis sam-hym-c000749b profile 1.jpg
Queen with enlarged gaster

The size of worker ants varies between 5–18 millimetres (0.20–0.71 in), with larger workers making up to 50 percent of the colony. [8] Though it was often suggested that the larger ants also function as gamergates, [9] they were never observed laying fertile eggs, a function solely reserved to the ergatoid queen. [5] Even though M. analis is often referred to as dimorphic, with a major and minor caste, they actually exhibit polyphasic allometry[ clarification needed ] in worker sizes. The variations among the ants are mostly in size and pubescence (with minors having less), although differences in the mandibles have also been observed, with minors having smoother mandibles compared to majors. [4]

Range and habitat

Megaponera analis occurs throughout sub-Saharan Africa from 25° S to 12° N. [2] Its nests are generally subterranean, up to 0.7 metres (2 ft 4 in) deep, and often located next to trees, rocks, or abandoned termite hills. [10] While the nest itself may have more than one entrance, it comprises only one chamber in which the eggs, larvae, cocoons, and the queen are located. [11] Frogs of the species Phrynomantis microps are sometimes found in the nests, and have evolved a skin secretion that inhibits the ants aggression.

Behaviour

An M. analis raiding column Megaponera analis raiding column.jpg
An M. analis raiding column
Ants returning from a raid in Yankari Game Reserve, Bauchi, Nigeria Matabele ants.jpg
Ants returning from a raid in Yankari Game Reserve, Bauchi, Nigeria

Raiding behaviour

M. analis ants breaking up the protective soil layer of a termite feeding site Megaponera analis raiding termites.jpg
M. analis ants breaking up the protective soil layer of a termite feeding site

The raiding activity of M. analis focuses on dawn and dusk between 6:00–10:00 and 15:00–19:00, [11] [12] with approximately three to five raids occurring per day. There are also observations of a third raiding activity window during the night between 22:00–2:00, although this phase has been poorly studied. [10] M. analis raids focus solely on termites from the subfamily Macrotermitinae and generally consist of 200 to 500 ants. [8]

The general foraging pattern of M. analis starts with scout ants searching an area of approximately 50 m (160 ft) around the nest for termite foraging sites. This searching phase can last up to one hour, and if it is unsuccessful the scout returns to the nest by a circuitous route. If a scout ant finds a potential site, it will start to investigate it without getting into contact with the termites or entering the galleries, before returning by the quickest route to recruit its nestmates to conduct a raid. [8] While the quickest route is often also the shortest, this is not always the case. Scouts have been observed to use deviations on open terrain (like paths) on which they can run twice as fast to reduce travel time on average by 35%. [13]

Although the scout ant is observed to lay a pheromone trail on the return journey to the nest, the other ants seem to be unable to follow this trail without the help of the scout. [10] The scout ant therefore leads the raid from the front, with the other ants following in a column-like formation. [14] Recruitment time varies between 60 and 300 seconds, with all castes taking part in a raid. During the outward journey towards the termites, all ants are laying a pheromone trail, making it much easier for them to find their way back to the nest later without having to rely on the scout ant. [15]

Approximately 20–50 cm (7.9–19.7 in) before contact with the termites, the raiding column stops and agglomerates until all the ants in the column have arrived, forming a sort of circle around the raid leader (the scout). Afterwards the ants rush forward towards the termites in an open formation and overwhelm their prey. During the attack, a division of labour can be observed. While the majors focus mostly on breaking up the protective layer over the foraging galleries of the termites, the minors rush into the galleries to kill the termites through the created openings. [8] After a foraging site has been exploited, the ants congregate at the same place they waited earlier, with the majors carrying the termites, and return to the nest in a column-like formation. These raids are always a single event and ants do not return independently to re-exploit a former raiding site, although the possibility of the scout ant remembering a site and reinvestigating it in the future for a possible second raid cannot be excluded. [16]

Colony size and reproduction

M. analis male Megaponera analis male.jpg
M. analis male

Colony size varies, depending on the location and age of the colony, from 440 to 2300 adult ants. [4] Little is known about the reproduction of M. analis. The alate males of M. analis are often observed leaving and entering the nests of established colonies by using pheromone trails from previous raids as guides to the nest. [17] Since M. analis colonies are obligate termite hunters, a queen could not establish a nest on her own, since she could not conduct a raid against termites without a standing army of worker ants. It is therefore assumed that new colonies are always created through colony fission, with the new queen taking a number of the workers of the old colony with her to create a new colony. [5]

Helping behaviour

Cooperative self defence

While cooperative defence of the nest is well known in ants, [5] cooperative self-defence outside of the nest is much less so. When M. analis ants are attacked by driver ants (Dorylus sp.) outside of the nest, they cooperate with one another in an attempt to defend themselves by checking each other's extremities for enemy ants and removing any that are clinging to their legs or antennae. [18]

Saving injured individuals

During the battle against termites some of the ants get injured. The termite soldiers are able to bite off extremities or cling on to the ant body after their death. These ants have evolved a unique mechanism to deal with this increased foraging cost. The battle injured ants "call" for help with a pheromone in their mandibular gland (consisting of two chemical compounds: dimethyl disulfide and dimethyl trisulfide), attracting nestmates, which then start to investigate the injured nestmate, pick her up, and carry the injured ant back to the nest. By doing so, they reduce their mortality rate of 32% to close to zero. Inside the nest the clinging termites get removed. In case they lost one or two legs the ants adapt to a four or five legged locomotion to compensate for it, allowing them to reach running speeds similar to a healthy ant. These injured ants are then capable again of performing colony tasks and are even observed in future raids against termites. A model calculated the value of this rescue behaviour to allow a colony to be 28.7% larger than a colony that would not show this behaviour (due to the energy saving by not having to replace the injured workers with new healthy replacements). This is the only invertebrate species known to show such a behaviour towards injured individuals. [19]

The rescue behaviour is also limited to only lightly injured ants (loss of 1-2 limbs); heavily injured ants (that have lost 3 or more limbs) are left behind on the hunting ground. The mechanism with which this is regulated is believed to be relatively simple and based on a two-step process: after an ant is injured the first step is for it to try standing normally on its legs again ("return to an idling position"). Step two is to call for help and cooperate with the responding helpers, but if step one cannot be achieved, then step two will not occur. Heavily injured ants are therefore in a constant loop trying to achieve step one, making it a very simple mechanism of only rescuing ants that are still useful for the colony. [20]

Megaponera injured ant investigated.jpg
Injured ant (termite bites) being investigated by nestmate at the hunting ground
Megaponera (injured carried).jpg
Injured ant being carried back to the nest

Treatment of injured ants

M. analis ant treating the wound of an injured nestmate in the nest Megaponera Wound treatment.jpg
M. analis ant treating the wound of an injured nestmate in the nest

Observations inside the nest have revealed that these ants treat the wounds of their injured nest-mates, making them the first recorded non-human species to consistently take care of the wounds of other individuals. Nest mates grab the damaged limb of the injured ant in their mandibles and hold it in place with their front legs. They then start to "lick" the wound for numerous minutes. This treatment occurs predominantly within the first hour after injury. Without treatment, the typical mortality rate of injured ants is 80%. [20] Wounds often get infected by opportunistic pathogens on the soil surface entering the wound. A major, lethal pathogen in this regard for M. analis is Pseudomonas aeruginosa. Wounds exposed to this pathogen lead to a mortality of close to 90%. Infected ants signal their infected wounds through changes in their cuticular hydrocarbon profile, allowing nestmates to recognise infected wounds and tream them accordingly. This second, therapeutic care phase also includes the application of the secretions from the metapleural gland, which harbor over 100 antimicrobial compounds and proteins. This specialised antimicrobial wound care allows the ants to successfully treat infected wounds, allowing the injured ants to recover from their injuries. [21]

See also:

Related Research Articles

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<span class="mw-page-title-main">Trophallaxis</span> Transfer of food between members of a community through stomodeal or proctodeal means

Trophallaxis is the transfer of food or other fluids among members of a community through mouth-to-mouth (stomodeal) or anus-to-mouth (proctodeal) feeding. Along with nutrients, trophallaxis can involve the transfer of molecules such as pheromones, organisms such as symbionts, and information to serve as a form of communication. Trophallaxis is used by some birds, gray wolves, vampire bats, and is most highly developed in eusocial insects such as ants, wasps, bees, and termites.

<span class="mw-page-title-main">Ponerinae</span> Subfamily of ants

Ponerinae, the ponerine ants, is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including Dinoponera gigantea - one of the world's largest species of ant. Mated workers have replaced the queen as the functional egg-layers in several species of ponerine ants. In such queenless species, the reproductive status of workers can only be determined through ovarian dissections.

<i>Myrmecia</i> (ant) Genus of ants

Myrmecia is a genus of ants first established by Danish zoologist Johan Christian Fabricius in 1804. The genus is a member of the subfamily Myrmeciinae of the family Formicidae. Myrmecia is a large genus of ants, comprising at least 93 species that are found throughout Australia and its coastal islands, while a single species is only known from New Caledonia. One species has been introduced out of its natural distribution and was found in New Zealand in 1940, but the ant was last seen in 1981. These ants are commonly known as bull ants, bulldog ants or jack jumper ants, and are also associated with many other common names. They are characterized by their extreme aggressiveness, ferocity, and painful stings. Some species are known for the jumping behavior they exhibit when agitated.

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

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<i>Harpegnathos saltator</i> Species of ant

Harpegnathos saltator, sometimes called the Indian jumping ant or Jerdon's jumping ant, is a species of ant found in India. They have long mandibles and have the ability to leap a few inches. They are large-eyed and active predators that hunt mainly in the early morning. The colonies are small and the difference between workers and queens is very slight.

<i>Nothomyrmecia</i> Genus of ants

Nothomyrmecia, also known as the dinosaur ant or dawn ant, is an extremely rare genus of ants consisting of a single species, Nothomyrmecia macrops. These ants live in South Australia, nesting in old-growth mallee woodland and Eucalyptus woodland. The full distribution of Nothomyrmecia has never been assessed, and it is unknown how widespread the species truly is; its potential range may be wider if it does favour old-growth mallee woodland. Possible threats to its survival include habitat destruction and climate change. Nothomyrmecia is most active when it is cold because workers encounter fewer competitors and predators such as Camponotus and Iridomyrmex, and it also increases hunting success. Thus, the increase of temperature may prevent them from foraging and very few areas would be suitable for the ant to live in. As a result, the IUCN lists the ant as Critically Endangered.

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

The green-head ant is a species of ant that is endemic to Australia. It was described by British entomologist Frederick Smith in 1858 as a member of the genus Rhytidoponera in the subfamily Ectatomminae. These ants measure between 5 and 7 mm. The queens and workers look similar, differing only in size, with the males being the smallest. They are well known for their distinctive metallic appearance, which varies from green to purple or even reddish-violet. Among the most widespread of all insects in Australia, green-head ants are found in almost every Australian state, but are absent in Tasmania. They have also been introduced in New Zealand, where several populations have been established.

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<i>Plectroctena</i> Genus of ants

Plectroctena is an Afrotropical genus of ants, with most species occurring in the rainforest zones of West and Central Africa. Some species are cryptic or subterranean foragers, while others forage in open grassland terrain. The workers forage singly or in groups of 2 to 3. They nest in the earth at varying depths, or in collapsed logs. They prey mainly on millipedes, including their young or eggs.

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<span class="mw-page-title-main">Gamergate (ant)</span> Reproductively viable female worker ant

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<i>Phrynoponera</i> Genus of ants

Phrynoponera is a strictly Afrotropical genus of ants in the subfamily Ponerinae.

<i>Buniapone</i> Genus of ants

Buniapone is a monotypic genus of ants in the subfamily Ponerinae. Buniapone amblyops, the single described species, is found in Southern and Southeast Asia.

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

<i>Messor capitatus</i> Species of ant

Messor capitatus is an ant species part of the genus Messor. This genus includes about 40 specialized species that are found in dry areas of Mediterranean countries such as Africa, Southern Europe, and Asia.Messor capitatus are known as an Old World species because they release trail pheromones from the Dufour gland instead of from poison glands. Messor capitatus are known as individual foragers that collect food independently of one another but sometimes will also use group foraging to form irregular, broad columns. Messor capitatus main food source is seeds but they also will eat remains of plants and animals.

<i>Ectatomma opaciventre</i> Species of ant

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References

  1. 1 2 3 Schmidt, C.A.; Shattuck, S. O. (18 June 2014). "The Higher Classification of the Ant Subfamily Ponerinae (Hymenoptera: Formicidae), with a Review of Ponerine Ecology and Behavior". Zootaxa. 3817 (1): 1–242. doi:10.11646/zootaxa.3817.1.1. PMID   24943802.
  2. 1 2 Wheeler, William Morton (1936). "Ecological Relations of Ponerine and Other Ants to Termites". Proceedings of the American Academy of Arts and Sciences. 71 (3): 159–243. doi:10.2307/20023221. JSTOR   20023221.
  3. ↑ Wilson, Edward O. (2014). A Window on Eternity: A Biologist's Walk Through Gorongosa National Park. Simon & Schuster. p. 83. ISBN   978-1476747415.
  4. 1 2 3 Villet, Martin H. (1990). "Division of labour in the Matabele ant Megaponera foetens (Fabr.) (Hymenoptera Formicidae)". Ethology Ecology & Evolution. 2 (4): 397–417. doi:10.1080/08927014.1990.9525400.
  5. 1 2 3 4 Hölldobler, Bert; Wilson, Edward O. (1990). The Ants. Cambridge, Mass.: Belknap Press of Harvard University Press. ISBN   9780674040755.
  6. ↑ Mayr, G. (1862). "Myrmecologische Studien". Verh. K-K. Zool.-Bot. Ges. Wien12: 649–776 (page 714, Megaponera; (diagnosis in key) as genus; Megaponera in Ponerinae [Poneridae])
  7. ↑ Bolton, B. (1994). Identification guide to the ant genera of the world . Harvard University Press. pp.  222. ISBN   0-674-44280-6.
  8. 1 2 3 4 Longhurst, C.; Howse, P. E. (1979). "Foraging, recruitment and emigration in Megaponera foetens (Fab.) (Hymenoptera: Formicidae) from the Nigerian Guinea Savanna". Insectes Sociaux. 26 (3): 204–215. doi:10.1007/BF02223798. S2CID   24846197.
  9. ↑ Crewe, R. M.; Peeters, C. P.; Villet, M. (1984). "Frequency distribution of worker sizes in Megaponera foetens". South African Journal of Zoology. 19 (3): 247–248. doi:10.1080/02541858.1984.11447886. ISSN   0254-1858.
  10. 1 2 3 Yusuf, Abdullahi A. (2010). Termite raiding by the ponerine ant Pachycondyla analis (Hymenoptera: Formicidae) (Ph.D.). University of Pretoria.
  11. 1 2 Lepage, M. G. (1981). "Étude de la prédation de Megaponera foetens (F.) sur les populations récoltantes de Macrotermitinae dans un ecosystème semi-aride (Kajiado-Kenya)". Insectes Sociaux. 28 (3): 247–262. doi:10.1007/BF02223627. S2CID   28763771.
  12. ↑ Levieux, Jean (1966). "Note préliminaire sur les colonnes de chasse de Megaponera fœtens F. (Hyménoptère Formicidæ)". Insectes Sociaux. 13 (2): 117–126. doi:10.1007/BF02223567. S2CID   2031222.
  13. ↑ Frank, E.; Hönle, P.; Linsenmair, K. (2018). "Time optimized path-choice in the termite hunting ant Megaponera analis". Journal of Experimental Biology. 221 (13): jeb174854. doi: 10.1242/jeb.174854 . PMID   29748213.
  14. ↑ Bayliss, J.; Fielding, A. (2002). "Termitophagous foraging by Pachycondyla analis (Formicidae, Ponerinae) in a Tanzanian coastal dry forest" (PDF). Sociobiology. 39: 103–122. Archived from the original (PDF) on 2014-06-04. Retrieved 2014-10-21.
  15. ↑ Hölldobler, Bert; Braun, Ulrich; Gronenberg, Wulfila; Kirchner, Wolfgang H.; Peeters, Christian (1994). "Trail communication in the ant Megaponera foetens (Fabr.) (Formicidae, Ponerinae)". Journal of Insect Physiology. 40 (7): 585–593. doi:10.1016/0022-1910(94)90145-7.
  16. ↑ Longhurst, C.; Baker, R.; Howse, P. E. (1979). "Termite predation by Megaponera foetens (FAB.) (Hymenoptera: Formicidae)". Journal of Chemical Ecology. 5 (5): 703–719. doi:10.1007/BF00986555. S2CID   19727605.
  17. ↑ Longhurst, C.; Howse, P. E. (1979). "Some Aspects of the Biology of the Males of Megaponera Foetens (Fab.) (Hymenoptera: Formicidae)". Insectes Sociaux. 26 (2): 85–91. doi:10.1007/BF02223502. S2CID   26624905.
  18. ↑ Beck, J.; Kunz, K. (2007). "Cooperative self-defence: Matabele ants (Pachycondyla analis) against African driver ants (Dorylus sp.; Hymenoptera: Formicidae)". Myrmecological News. 10: 27–28.
  19. ↑ Frank, Erik Thomas; Schmitt, Thomas; Hovestadt, Thomas; Mitesser, Oliver; Stiegler, Jonas; Linsenmair, Karl Eduard (12 April 2017). "Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis". Science Advances. 3 (4): e1602187. doi:10.1126/sciadv.1602187. PMC   5389746 . PMID   28439543.
  20. 1 2 Frank, Erik Thomas; Wehrhahn, Marten; Linsenmair, Karl Eduard (14 February 2018). "Wound treatment and selective help in a termite-hunting ant". Proceedings of the Royal Society B. 285 (1872): 20172457. doi:10.1098/rspb.2017.2457. PMC   5829198 . PMID   29445019.
  21. ↑ Frank, Erik Thomas; Kesner, Lucie; Liberti, Joanito; Helleu, Quentin; LeBoeuf, Adria; Sponsler, Douglas; Azuma, Fumika; Economo, Evan; Waridel, Patrice; Engel, Philipp; Schmitt, Thomas; Keller, Laurent (29 December 2023). "Targeted treatment of injured nestmates with antimicrobial compounds in an ant society". Nature Communications. 14: 8446. doi:10.1038/s41467-023-43885-w. PMC   10756881 .
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