Myrmecia nigriceps

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Myrmecia nigriceps
Myrmecia nigriceps worker from Strangways, Victoria
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmeciinae
Genus: Myrmecia
Species:
M. nigriceps
Binomial name
Myrmecia nigriceps
Mayr, 1862[1]
Synonyms
  • Myrmecia fasciata (Clark, 1951)

Myrmecia nigriceps, also known as the black-headed bull ant, is a species of ant endemic to Australia. A member of the genus Myrmecia in the subfamily Myrmeciinae, it was first described by Austrian entomologist Gustav Mayr in 1862. These ants are large, varying from 19 to 23 millimetres (0.75 to 0.91 in) in length. However, colonies contain workers that are much smaller, usually half the size of normal workers. The queens are the largest while the males are the smallest, which can be easily identified due to their small mandibles.

Mainly nocturnal M. nigriceps is found in hot hilly areas and woodland, nesting underground in mounds. The ant's diet consists of sweet liquids from flowering plants and invertebrate prey, which are fed to the carnivorous larvae. Spiders are known to eat these ants, and echidnas consume the larvae and pupae. Like other Myrmecia species, M. nigriceps ants possess a powerful and painful sting, and the venom is capable of inducing allergic reactions in sensitive people.

Taxonomy

First identified by

Nothomyrmecia macrops).[7][8]

Myrmecia nigriceps is a member of the M. gulosa

Latin words niger, meaning "black", and caput, meaning "head". This references the distinctive black head of the ant. With this said, M. nigriceps is commonly known as the black-headed bull ant.[9]

Description

Front view
Side view
Top view

The size of worker ants varies from 19 to 23 millimetres (0.75 to 0.91 in). However, colonies contain very small workers, usually less than half the size of normal sized workers. Despite this, it is not known if M. nigriceps is polymorphic, due to little differences in morphology between the workers in comparison to Formicinae ants and Pheidole, with soldiers having enormous heads.[10] The queens are the largest, measuring around 24 to 26 millimetres (0.94 to 1.02 in), and males being around similar sizes to worker ants at 18 to 20 millimetres (0.71 to 0.79 in).[11] The head and gaster are black, and the thorax, node, and postpetiole are either red or yellowish red, while the antennae and legs are either yellow or testaceous. The mandibles and clypeus are also yellow.[11] The hair is short and yellow in colour, erect on the body and suberect on the legs. The pubescence (short, fine, soft hair) is white and abundant all over the postpetiole and gaster. The head is almost as broad as its total length, and the mandibles are longer than the head with 13 teeth present.[11]

The queen is similar in appearance to the worker, but they are the largest members of the colony. The hair is more abundant, and the head is broader. The mandibles are shorter and broader, although they are still as long as the head.[11] The wings are yellowish in colour and translucent in appearance. Males are the smallest members of the colony and can be easily identifiable by their perceptibly smaller mandibles. The hairs on males are the longest and most abundant among the worker and queen castes, with a long and broad head.[11]

Myrmecia nigriceps is similar in appearance to M. vindex, but several morphological characters distinguish these two species from each other. For example, M. nigriceps is generally larger than M. vindex, and its head is either black or dark brown; the head is broader and more rectangular in workers. The

thorax and pedicel are noticeably darker and brownish red. The nests and behaviour, however, of both ants are similar to each other.[5]

Distribution and habitat

Myrmecia nigriceps is distributed throughout

plateaus, woodland, native vegetation, hot hilly areas covered with scrubby vegetation and in rehabilitated sites, at elevations ranging from 300 to 460 metres (1,000 to 1,500 ft).[13][14][15][16]

Myrmecia nigriceps is a mound constructing species, although colonies can be found under logs.[5][17] Workers decorate the nest with a variety of items, including lateritic pebbles and soil crumbs, in a similar fashion of meat ant (Iridomyrmex purpureus) nests.[17] Other items used for nest decorating include small stones and plant material.[18]

Behaviour and ecology

Worker grooming herself

Myrmecia nigriceps ants are

Camponotus workers and males.[5][18][22] Cockroaches, such as Platyzosteria castanea and Platyzosteria ruficeps, can repel attacks by M. nigriceps by discharging a secretion that disorientates the attacking workers.[23] Workers begin to forage one hour before sunset, with peak activity occurring during the twilight hours. These ants have excellent vision, having the largest eye lenses and photoreceptors than any other Myrmecia ant.[20] These ants are capable of discriminating the distance and size of objects moving nearly a metre away, sensitive to motion and will rapidly charge towards any moving objects to attack it.[24]

These ants are preyed on by the short-beaked echidna (Tachyglossus aculeatus), and by spiders in the genus Zenodorus, particularly Zenodorus metallescens.[25][26] Blindsnakes are known to consume the larvae and pupae of these ants.[27] Colonies are also a host for M. inquilina, a social parasite that lays its eggs inside the colony.[28]

Myrmecia nigriceps is an extremely aggressive ant, and larger colonies may rival other colonies of a different Myrmecia species (such as M. gulosa) in terms of fierceness and pugnacity.[5] While the mandibles cause little to no pain in humans, the ant is equipped with a painful and powerful sting that is found at the end of the gaster. Like other ants, the sting is not barbed, and workers are able to sting multiple times without injuring themselves.[29] With a median lethal dose (LD50) of 7.3 mg/kg, the venom is relatively weak in comparison to other Myrmecia ants, whose LD50 is much lower.[a][31] However, in a 2011 study, at least one patient had an allergic reaction to M. nigriceps venom. This study also concluded that many other Myrmecia species can cause anaphylaxis, as well as the Green-head ant (Rhytidoponera metallica).[32] In the Starr sting pain scale, a scale which compares the overall pain of hymenopteran stings on a four-point scale, the sting of M. nigriceps was ranked as two in pain, described as "painful".[33] M. nigriceps ants are able to enter colonies they do not reside in without being attacked; this may be due to these ants failing to recognise foreigners, or the consequences of ignoring workers from other colonies is low.[34][35]

Nuptial flight occurs after rain for several days, taking place between December and March. The males and virgin queens emerge from their nest, and unlike other species who mate on the ground or climb onto nearby trees or branches to fly off from, the reproductive alates will fly from the nest. Recorded nuptial flights usually took place on hilltops.[21] M. nigriceps queens are not known to seal up their entrance during colony foundation, unlike other Myrmecia species such as M. regularis.[36] Workers can live exceptionally long, with an average lifespan of 2.2 years; maximum longevity in workers varied from 2.1 to 2.4 years.[37][38][39]

See also

Notes

  1. ^ Some tested Myrmecia species have an LD50 value of 0.18–0.35 mg/kg.[30]

References

  1. ^ Johnson, Norman F. (19 December 2007). "Myrmecia nigriceps Mayr". Hymenoptera Name Server version 1.5. Columbus, Ohio, USA: Ohio State University. Retrieved 1 April 2015.
  2. doi:10.5281/zenodo.25912
    .
  3. ^ Forel, Auguste (1907). Formicidae. In Michaelsen & Hartmeyer. Die Fauna Südwest-Australiens. Ergebnisse der Hamburger-Südwest-Australischen Forschungsreise 1905 (PDF) (in German). Gustav Fischer, Jena. p. 264.
  4. doi:10.5281/zenodo.25595
    .
  5. ^
    OCLC 1411297
    .
  6. ^
    doi:10.1080/00222939100771021
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  7. PMID 15899976
    .
  8. doi:10.1603/0013-8746(2006)99[487:BAOTEO]2.0.CO;2
    .
  9. ISBN 978-0-7270-1165-7
    .
  10. ^ McAreavey, John (1948). "Observations on Myrmecia tarsata Smith". Proceedings of the Linnean Society of New South Wales. 73: 137–141.
  11. ^ a b c d e f Clark, John (1951). The Formicidae of Australia Volume 1. Subfamily Myrmeciinae (PDF). Melbourne: Commonwealth Scientific and Industrial Research Organisation, Australia. pp. 64–66.
  12. doi:10.5281/zenodo.26621
    .
  13. JSTOR 25003349
    .
  14. ^ "Species: Myrmecia nigriceps". AntWeb. California Academy of Sciences. Retrieved 26 August 2015.
  15. doi:10.1046/j.1442-9993.2003.01312.x
    .
  16. ISBN 978-0-644-03922-2
    .
  17. ^ a b Conole, Lawrence E. (1993). "Observations of nest mound decoration by the bulldog ant Myrmecia forficata and other Myrmecia species in south-west Victoria". The Victorian Naturalist. 110 (5): 217–218.
  18. ^
    S2CID 31047636
    .
  19. ^ Brown, William (1953). "Revisionary notes on the ant genus Myrmecia of Australia" (PDF). Bulletin of the Museum of Comparative Zoology. 111 (6): 1–35.
  20. ^
    S2CID 35467027
    .
  21. ^
    PMID 20926444
    .
  22. JSTOR 2422136
    .
  23. S2CID 1047249
    .
  24. doi:10.1242/jeb.119.1.115
    .
  25. doi:10.1111/j.1469-7998.1992.tb04399.x
    .
  26. S2CID 83504302
    .
  27. doi:10.1163/156853889X00430
    .
  28. S2CID 34794416
    .
  29. doi:10.5281/zenodo.26623
    .
  30. ISBN 978-1-4020-6242-1
    .
  31. ISBN 978-0-88706-896-6
    .
  32. S2CID 20021826
    .
  33. doi:10.18474/0749-8004-20.2.225
    .
  34. ISBN 978-0-691-13879-4
    .
  35. S2CID 2271439
    .
  36. doi:10.1071/ZO9580001
    .
  37. ISBN 978-0-691-05924-2
    .
  38. ISBN 978-0-674-04075-5
    .
  39. S2CID 26383105
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Myrmecia_nigriceps&oldid=1223598120"