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Microhodotermes viator

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Microhodotermes viator
Soldier and winged reproductive castes of Microhodotermes viator
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Blattodea
Infraorder: Isoptera
Family: Hodotermitidae
Genus: Microhodotermes
Species:
M. viator
Binomial name
Microhodotermes viator
(Latreille, 1804)
Synonyms[1]
  • Termes viator (Latreille, 1804)
  • Hodotermes (Hodotermes) faurei (Fuller, 1921)
  • Hodotermes (Hodotermes) peringueyi (Fuller, 1921)
  • Hodotermes (Hodotermes) silvestrii (Fuller, 1921)
  • Hodotermes (Hodotermes) thomseni (Fuller, 1921)
  • Hodotermes viator hageni (Fuller, 1921)
  • Hodotermes aurivillii (Sjöstedt, 1900)

Microhodotermes viator, commonly called the southern harvester termite,[2] the Karoo harvesting termite,[3] the wood-eating harvester termite,[4] houtkapper (lit. 'wood cutter'), and stokkiesdraer (lit. 'stick carrier'),[5] is a species of harvester termite native to the desert shrubland of Namibia and South Africa. The eusocial insects inhabit soil mounds called heuweltjies. In 2024, researchers found inhabited Microhodotermes viator mounds up to 34,000 years old—by far the oldest active termite structures ever dated.[6]

Description[edit]

A worker termite

The holotype, collected and first described by Pierre André Latrielle in 1804, has a clear red-brown head with a width of 3.8 mm. The unusually large head of M. viator is distinctive among Hodotermitidae. On its head are sharply-defined bright yellow pseudo-ocelli. The body is an opaque yellow-orange, with a dark band in the transverse furrow of the prothorax, and the legs are pale yellow.[7] Claude Fuller described the legs as brown or red-brown, with the tarsi and the tips of the tibiae and femora being yellow.[7]

Latrielle described the larva as having a light brown body and a large brown head, distinctly faceted black eyes, and yellow ocelli.[7]

The species is polymorphic, having different forms for different castes, and sexually dimorphic. Males are often larger than females.[7] Soldier termites have long, thin jaws that curve inward only at their tips, and body lengths of 7–13 mm, while workers have indistinctly striped brown abdomens and body lengths between 6–8 mm.[8] Alates have an average body length of 14.01 mm.[9]

Distribution and habitat[edit]

Microhodotermes viator is found in South Africa and Namibia, particularly on the west coast.[10] It is found mainly in scrubland with annual precipitation of 125–750mm.[11] The precise range of M. viator has not been mapped.[12] M. viator colonies in Namaqualand experience a warm and dry climate, with no perennial rivers in the area.[13]

Behavior[edit]

Microhodotermes viator are eusocial insects, forming colonies of several thousand with castes of workers and soldiers.[14] They are foragers of plant material emerging during the day in winter and during the night in summer.[15] A 1993 study suggests that M. viator thwarts predators by emerging to forage at unpredictable times of day, irrespective of temperature, humidity, and rainfall.[15] Foraging M. viator work in groups to cut plants, particularly grass stalks[14] and woody plants (particularly Pteronia),[8] in pieces 1–2 cm long[16] and carry them back to the nest ithrough subsurface tunnels to be stored in underground chambers. They digest cellulose, making them extremely important decomposers in the microorganism-poor desert biomes they inhabit.[14]

Nesting[edit]

The large spots of reduced vegetation are heuweltjies, which are inhabited by Microhodotermes viator and cover 20% of South Africa's west coast.

Colonies of Microhodotermes viator form nests, including in regularly-spaced[17] circular mounds of earth called heuweltjies (meaning 'little hills'),[13][15] which when viewed from above resemble large fairy circles.[18] Heuweltjies inhabited by M. viator cover over 20% of South Africa's west coast, including the Fynbos and Succulent Karoo biomes,[19] and can reach up to 40 metres (130 ft) in diameter and 2 metres (6.6 ft) in height.[13] There has been debate as to whether the heuweltjies are directly constructed by termites or if their formation is the product of erosion, both termite-influenced and not.[20] The distribution of heuweltjies represents roughly 49% of the distribution of M. viator.[12] M. viator colonies outside of the Succulent Karoo and Nama Karoo biomes do not form mounds; they live in nests a few metres underground.[14] Studies investigating the role of M. viator in heuweltjie formation have found that the termites formed them indirectly as ecosystem engineers by enriching the soil around their nests with organic matter, which has promoted growth of widely separated patches of vegetation that in turn influenced wind erosion to form the mounds.[20][21] The soil chemistry of the heuweltjies is different from the surrounding soil, with mineral enrichments that align with those associated with other termite formations.[17] The even spacing of the mounds is explained by proponents of the zoogenic hypothesis as being a result of competition between colonies for space and vegetation.[14]

The superficial sand on heuweltjies inhabited by M. viator is also host to other termites, ants, burrowing bees, mole-rats, and aardvarks, all of whom actively rework the earth. The subsurface structure of the mounds, though, is dominated by the complex of tunnels and chambers constructed by M. viator. A study of mounds on the western bank of Clanwilliam Dam in South Africa, found active M. viator habitation in 78.9% of intact mounds, as indicated by piles of fresh frass.[17]

A worker moving a stick

The structures formed by M. viator are described as having four principal forms: anastomosing tubular tunnels 3 mm–1 cm wide; hundreds[14] of straight tunnels extending with ellipsoidal cross-sections greater than 1 cm in width, which extended several metres radially from the mound's central depression to its periphery and beyond (apparently access ways connecting the hive to storage chambers and foraging sites), oval- or kidney-shaped chambers for the temporary storage of vegetation and cut twigs, generally 5–6 by 3–4 cm with a polished interior surface, and a delicate complex of horizontal shelves made of compacted organic material, which constituted the hive itself.[17] The hive is roughly spherical and ranged from 0.3–1 m in diameter.[5]

A 1991 study of calcified mounds inhabitied by M. viator found them to be 4,000 to 5,500 years old. Fossil termite structures were found in the mounds, indicating that the termite colonies had been inhabiting their mounds throughout the period.[17] In 2024, a team of researchers used carbon dating on inhabited M. viator mounds along the Buffels River in Namaqualand to discover that they were 34,000 years old—before the Last Ice Age[22]—making them the oldest inhabited termite features ever dated. The study also found that the mounds contained organic material up to 19,000 years old buried deep within the mound, with the younger material being buried lower down at depths greater than 1 metre (3.3 ft). This led researchers to describe the inhabited termite mounds as "ancient carbon reservoirs".[13]

Symbiosis and parasites[edit]

Crustaceans[edit]

A number of termitophilous isopods live in the nests and foraging cells of M. viator colonies, including Phylloniscus braunsi, Titana mirabilis, Coatonia phylloniscoides, and Antidorcasia elongata.[a] The isopods, who are found in the nests of numerous termite species, most likely have an obligatory relationship with their termite hosts, probably living as scavengers feeding on detritus within the nest. The Titaniidae are either tolerated by their hosts, or are protected from attack by their speed and by their flat, horseshoe crab-like body shapes.[23]

Insects and springtails[edit]

In the scarab family, the flower chafers Elpidus hopei, Xiphoscelis gariepina, and Trichoplus agis are termitophiles associated with M. viator,[24] and T. aepytus, a dark brown Cremastocheilinus, is often found in Microhodotermes viator mounds in Namaqualand.[25][24] The rove beetles Termitoletus schultzei,[26] T. neoschultzei, T. niger, T. coatoni, T. sheasbyi, and Hodoxenus sheasbyi,[24] and the clown beetles Monoplius pinguis, M. inflatus, and M. peringueyi, live in Microhodotermes viator nests,[24] as do the primitive insects of the order Zygentoma Dinatelura afra, D. primitiva,[27] Silvestrella termitophila, S. myrmecophila,[28] Rulenatida apprima, Rulenatida primitiva, Natiruleda magnifica, Pseudaletura trichophila, Linadureta versicolor, Eluratinda sheasbyi, Eluratinda coatoni, and Ctenolepisma intercursa.[29] H. sheasbyi is described as highly integrated into the society of its termite hosts. The beetles antennate soldier termites and offer the tips of their abdomens to the termites, who in turn seem to drink from the tip. The opposite situation, with the beetles drinking from the termites' abdomens after antennation, has also been observed.[30]

The elongate-bodied Paronellid springtail Cyphoderus collurus is a termitophile associated with M. viator.[24]

Protozoa[edit]

The flagellate form of the protozoan Gigantomonas herculea parasitizes Microhodotermes viator.[31]

Predation[edit]

Ouroborus cataphractus (pictured here in its defensive posture, which resembles an ouroboros) feeds on southern harvest termites that emerge in large numbers after spring rains

Arthropods[edit]

A major predator of Microhodotermes viator is Pachycondyla hottentota, a specialized ant that catches termites as they return to foraging ports.[15] Another specialized predator is the spider Ammoxenus daedalus. A. daedalus apparently feeds only on smaller worker termites, and "detects their suitability as prey items by touch". When a group of foraging termites is attacked, they respond by overwhelming the area with large workers so as to prevent the spider from finding a small enough termite to eat.[11] Other predators include the ant Ocmyrmex cillei[15] and the invasive Argentine ant.[32]

The sand termite Psammotermes allocerus feeds on organic matter in the waste dumps of M. viator.[33]

Vertebrates[edit]

M. viator is possibly the most important prey item of Armadillo girdled lizard (Ouroborus cataphractus), which "feeds ferociously" on the large numbers of termites that appear just after the spring rains.[34] The termites are also eaten by the lark Mirafra apiata, commonly known as the Cape clapper lark.[35] The aardvark is a predator of M. viator, and a study of mounds near Clanwilliam Dam in South Africa found that 53.16% of intact mounds bore signs of aardvark excavation. Many of the mounds bearing signs of aardvark predation were still active, indicating that M. viator colonies are capable of surviving aardvark predation events.[17]

The larvae of M. viator are recorded as being eaten by humans in South Africa.[36]

References[edit]

  1. ^ "Microhodotermes viator (Latreille, 1804) | COL". www.catalogueoflife.org. Retrieved 2024-07-05.
  2. ^ McAuliffe, Joseph R.; Hoffman, M. Timm; McFadden, Leslie D.; Bell, Wesley; Jack, Sam; King, Matthew P.; Nixon, Veronica (2019-03-01). "Landscape patterning created by the southern harvester termite, Microhodotermes viator: Spatial dispersion of colonies and alteration of soils". Journal of Arid Environments. 162: 26–34. doi:10.1016/j.jaridenv.2018.11.010. ISSN 0140-1963.
  3. ^ van Ark, H. (1969). "Control of the Karoo harvesting termite, Microhodotermes viator (Latreille) (Hodotermitidae, Isoptera)". Phycophylactica. 1 (1): 1–8 – via Sabinet African Journals.
  4. ^ Suttie, J. M.; Reynolds, Stephen G.; Batello, Caterina; Food and Agriculture Organization of the United Nations, eds. (2005). Grasslands of the world. Plant production and protection series. Rome: Food and Agricultural Organization of the United Nations. p. 98. ISBN 978-92-5-105337-9. OCLC 61697614.
  5. ^ a b Annecke, David P.; Moran, V. Cliff (1982). Insects and mites of cultivated plants in South Africa. Durban Woburn, Mass: Butterworths. ISBN 978-0-409-08398-9.
  6. ^ "34,000-year-old termite mounds in South Africa are still being used". Mongabay Environmental News. 2024-06-28. Retrieved 2024-07-05.
  7. ^ a b c d Fuller, Claude (1921). "The termites of South Africa". South African journal of natural history. 3 (1): 14–52.
  8. ^ a b Picker, Mike; Griffiths, Charles; Weaving, Alan (2002). Field Guide to Insects of South Africa. Penguin Random House South Africa. ISBN 978-1-86872-713-1.
  9. ^ Engel, Michael S.; Barden, Phillip; Riccio, Mark L.; Grimaldi, David A. (February 2016). "Morphologically Specialized Termite Castes and Advanced Sociality in the Early Cretaceous". Current Biology. 26 (4): 522–530. doi:10.1016/j.cub.2015.12.061. ISSN 0960-9822.
  10. ^ Krishna, K.; Grimaldi, D.A.; Krishna, V.; Engel, M.S. (2013). "Treatise on the Isoptera of the World: Basal Families". Bulletin of the American Museum of Natural History. 377 (2): 303–306. doi:10.1206/377.2. ISSN 0003-0090.
  11. ^ a b "Microhodotermes | Termites of the World". termites.myspecies.info. Retrieved 2024-07-05.
  12. ^ a b Cramer, Michael D.; von Holdt, Johanna R. C.; Uys, Vivienne M.; Midgley, Jeremy J. (2017-11-01). "The present and likely past climatic distribution of the termite Microhodotermes viator in relation to the distribution of heuweltjies". Journal of Arid Environments. 146: 35–43. doi:10.1016/j.jaridenv.2017.07.010. ISSN 0140-1963.
  13. ^ a b c d Francis, M.L.; Palcsu, L.; Molnár, M.; Kertész, T.; Clarke, C.E.; Miller, J.A.; van Gend, J. (May 2024). "Calcareous termite mounds in South Africa are ancient carbon reservoirs". Science of The Total Environment. 926: 171760. doi:10.1016/j.scitotenv.2024.171760. ISSN 0048-9697.
  14. ^ a b c d e f Lovegrove, Barry (6 January 2022). The Living Deserts of Southern Africa. Penguin Random House. ISBN 978-1775847045.
  15. ^ a b c d e Dean, W. Richard J.; Milton, Suzanne, eds. (28 June 1999). The Karoo: Ecological Patterns and Processes (1st ed.). Cambridge University Press. ISBN 978-0521554503.
  16. ^ Nel, J. J. C.; Walters, M. C.; Pretorius, M. W. (1974). "Pests of Pastures". Entomology Memoir. 41.
  17. ^ a b c d e f Moore, J. M.; Picker, M. D. (1991-05-01). "Heuweltjies (earth mounds) in the Clanwilliam district, Cape Province, South Africa: 4000-year-old termite nests". Oecologia. 86 (3): 424–432. doi:10.1007/BF00317612. ISSN 1432-1939.
  18. ^ Vlieghe, Kelly; Picker, Mike; Ross‐Gillespie, Vere; Erni, Birgit (February 2012). "Herbivory by subterranean termite colonies and the development of fairy circles in SW Namibia". Ecological Entomology. 40 (1): 42–49. doi:10.1111/een.12157. ISSN 0307-6946.
  19. ^ Clarke, C.E.; Vermooten, M.; Watson, A.; Hattingh, M.; Miller, J.A.; Francis, M.L. (May 2022). "Downward migration of salts in termite-affected soils: Implications for groundwater salinization". Geoderma. 413: 115747. doi:10.1016/j.geoderma.2022.115747. ISSN 0016-7061.
  20. ^ a b McAuliffe, Joseph R. (2023-08-28). "Earthen mounds ( heuweltjies ) of South Africa and their termite occupants: applicability of concepts of the extended phenotype, ecosystem engineering and niche construction". Philosophical Transactions of the Royal Society B: Biological Sciences. 378 (1884). doi:10.1098/rstb.2022.0150. ISSN 0962-8436. PMC 10331911. PMID 37427482.
  21. ^ McAuliffe, Joseph R.; Hoffman, M. Timm; McFadden, Leslie D.; Jack, Sam; Bell, Wesley; King, Matthew P. (2019-04-01). "Whether or not heuweltjies: Context-dependent ecosystem engineering by the southern harvester termite, Microhodotermes viator". Journal of Arid Environments. 163: 26–33. doi:10.1016/j.jaridenv.2018.11.012. ISSN 0140-1963.
  22. ^ Stellenbosch University (2024-06-10). Uncovering ancient termite wonders. Retrieved 2024-07-08 – via YouTube.
  23. ^ Kensley, Brian F. (15 October 1970). "Termitophilous Isopods from Southern Africa". Annals of the South African Museum. Annale van die Suid-Afrikaanse Museum. 57: 131–147 – via Biodiversity Heritage Library.
  24. ^ a b c d e Kistner, David H. (28 July 1969). "New Termitophilous Staphylinidae (Coleoptera) from Hodotermitidae (Isoptera) Nests". Journal of the New York Entomological Society. 78–79: 2–8.
  25. ^ Prins, A. J. (2 April 1984). "Morphological and Biological Notes on Some South African Arthropods Associated with Decaying Organic Matter Part 3: The Families Dermestidae, Cantharidae, Melyridae, Tenebrionidae, and Scarabaeidae (Coleoptera)". Annals of the South African Museum. Annale van die Suid-Afrikaanse Museum. 94: 258 – via Biodiversity Heritage Library.
  26. ^ Seevers, Charles (9 April 1957). Fieldiana: Zoology: Volume 40: A Monograph on the Termitophilous Staphylinidae (Coleoptera). Vol. v.40 (1957). Chicago: Chicago Natural History Museum. p. 250.
  27. ^ Paclt, J. (1902). "Thysanura Fam. Nicoletiidae". In Wytsman, P.; Townsend, Lee Hill (eds.). Genera insectorum (in Latin and French). Vol. 210–216. Bruxelles: L. Desmet-Verteneuil [etc.] p. 17.
  28. ^ Wytsman, P.; Wytsman, P.; Townsend, Lee Hill; Wytsman, P. (1902). Genera insectorum. Vol. 217c-219. Bruxelles: L. Desmet-Verteneuil [etc.]
  29. ^ Wygodzinsky, Pedro W. (1970). "Thysanura associated with termites in Southern Africa (Insecta). Bulletin of the AMNH ; v. 142, article 3". Bulletin of the American Museum of Natural History. 142 (3): 213–254.
  30. ^ "Hodoxenina". Forestis. February 27, 2001. Archived from the original on February 8, 2015. Retrieved February 12, 2015.
  31. ^ Kirby, H. (1946). "Gigantomonas herculea Dogiel, a polymastigote flagellate with flagellated and amoeboid phases of development". University Of California Publications In Zoology. 53.
  32. ^ Krishna, Kumar; Weesner, Frances M., eds. (1969). Biology of Termites. Academic Press.
  33. ^ Coaton, W.G.H. & Sheasby, J.L. (1973) The genus Psammotermes Desneux (Rhinotermitidae). National Survey of the Isoptera of South Africa. Series A. Cimbebasia, 3, 19–28.
  34. ^ le, P.; Mouton, F.N.; Geertsema, H.; Visagie, L. (April 2000). "Foraging mode of a group-living lizard, Cordylus cataphractus (Cordylidae)". African Zoology. 35 (1): 1–7. doi:10.1080/15627020.2000.11407185. ISSN 1562-7020.
  35. ^ Fry, C. H. (10 March 1992). "Myrmecophagy by Pseudochelidon eurystomina and other African birds". Bulletin of the British Ornithologists' Club. 112: 92.
  36. ^ Mitsuhashi, Jun (13 July 2016). Edible Insects of the World. CRC Press. ISBN 978-1498756570.
  1. ^ P. braunsi was found by researchers among M. viator nests in Aus, Namibia as well as in South Africa; the rest of the listed species were found in M. viator nests in South Africa.
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