Louse

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"Lice" redirects here. For the infection, see Pediculosis. For the district of Diyarbakır Province in Turkey, see Lice, Turkey. For the episode of The Office, see Lice (The Office). For other uses, see Louse (disambiguation).

Phthiraptera
Temporal range: Cenomanian–present
Light micrograph of Fahrenholzia pinnata
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Psocodea
Suborder: Troctomorpha
Infraorder: Nanopsocetae
Parvorder: Phthiraptera
Haeckel, 1896
Clades[1]

Louse (pl.: lice) is the common name for any member of the

parvorder, as a result of developments in phylogenetic research.[1][2][3]

Lice are

vectors of diseases such as typhus
.

Chewing lice live among the hairs or feathers of their host and feed on skin and debris, whereas sucking lice pierce the host's skin and feed on blood and other secretions. They usually spend their whole life on a single host, cementing their eggs, called nits, to hairs or feathers. The eggs hatch into nymphs, which moult three times before becoming fully grown, a process that takes about four weeks. Genetic evidence indicates that lice are a highly modified lineage of Psocoptera (now called Psocodea), commonly known as booklice, barklice or barkflies. The oldest known fossil lice are from the Cretaceous.[4]

Humans host two species of louse—the head louse and the body louse are subspecies of Pediculus humanus; and the pubic louse, Pthirus pubis. The body louse has the smallest genome of any known insect; it has been used as a model organism and has been the subject of much research. Lice were ubiquitous in human society until at least the Middle Ages. They appear in folktales, songs such as The Kilkenny Louse House, and novels such as James Joyce's Finnegans Wake. They commonly feature in the psychiatric disorder delusional parasitosis. A louse was one of the early subjects of microscopy, appearing in Robert Hooke's 1667 book, Micrographia.

Morphology and diversity

Lice are divided into two groups: sucking lice, which obtain their nourishment from feeding on the

phoresis to hitch a ride on a fly and attempt to find a new host.[6]

Sucking lice range in length from 0.5 to 5 mm (1⁄64 to 13⁄64 in). They have narrow heads and oval, flattened bodies. They have no

dorsally).[8] The thoracic segments are fused, the abdominal segments are separate, and there is a single large claw at the tip of each of the six legs.[7]

Chewing lice are also flattened and can be slightly larger than sucking lice, ranging in length from 0.5 to 6 mm (1⁄64 to 15⁄64 in). They are similar to sucking lice in form but the head is wider than the thorax and all species have compound eyes. There are no ocelli and the mouthparts are adapted for chewing. The antennae have three to five segments and are slender in the suborder Ischnocera, but club-shaped in the suborder Amblycera. The legs are short and robust, and terminated by one or two claws. Some species of chewing lice house symbiotic bacteria in bacteriocytes in their bodies. These may assist in digestion because if the insect is deprived of them, it will die. Lice are usually cryptically coloured to match the fur or feathers of the host.[7][9] A louse's color varies from pale beige to dark gray; however, if feeding on blood, it may become considerably darker.

Female lice are usually more common than males, and some species are parthenogenetic, with young developing from unfertilized eggs. A louse's egg is commonly called a nit. Many lice attach their eggs to their hosts' hair with specialized saliva; the saliva/hair bond is very difficult to sever without specialized products. Lice inhabiting birds, however, may simply leave their eggs in parts of the body inaccessible to preening, such as the interior of feather shafts. Living louse eggs tend to be pale whitish, whereas dead louse eggs are yellower.[5] Lice are exopterygotes, being born as miniature versions of the adult, known as nymphs. The young moult three times before reaching the final adult form, usually within a month after hatching.[5]

Humans host three different kinds of lice:

lice combs, and medicated shampoos or washes.[10]

Ecology

The average number of lice per host tends to be higher in large-bodied bird species than in small ones.[11] Lice have an aggregated distribution across bird individuals, i.e. most lice live on a few birds, while most birds are relatively free of lice. This pattern is more pronounced in territorial than in colonial—more social—bird species.[12] Host organisms that dive under water to feed on aquatic prey harbor fewer taxa of lice.[13][14] Bird taxa that are capable of exerting stronger antiparasitic defense—such as stronger T cell immune response or larger uropygial glands—harbor more taxa of Amblyceran lice than others.[15][16] Reductions in the size of host populations may cause a long-lasting reduction of louse taxonomic richness,[17] for example, birds introduced into New Zealand host fewer species of lice there than in Europe.[18][19] Louse sex ratios are more balanced in more social hosts and more female-biased in less social hosts, presumably due to the stronger isolation among louse subpopulations (living on separate birds) in the latter case.[20] The extinction of a species results in the extinction of its host-specific lice. Host-switching is a random event that would seem very rarely likely to be successful, but speciation has occurred over evolutionary time-scales so it must be successfully accomplished sometimes.[17]

Lice may reduce host life expectancy if the infestation is heavy,

helminth parasites,[22] but most individuals spend their whole life cycle on a single host and are only able to transfer to a new host opportunistically.[7] Ischnoceran lice may reduce the thermoregulation effect of the plumage; thus heavily infested birds lose more heat than others.[23]
Lice infestation is a disadvantage in the context of sexual rivalry.[24][25]

Evolution

Phthiraptera lice are members of

suborder Troctomorpha, and most closely related to the family Liposcelididae.[26] The oldest confirmed fossil louse is Archimenopon myanmarensis, an amblyceran from the Cretaceous amber from Myanmar.[4] Another early representative of the group is a bird louse, Megamenopon rasnitsyni, from Eckfelder Maar, Germany, which dates to the Eocene, around 44 million years ago.[27] Saurodectes vrsanskyi from the Early Cretaceous (Aptian) Zaza Formation of Buryatia, Russia, has also been suggested to be a louse, but this is tentative.[28]

Cladogram showing the position of Phthiraptera within Psocodea:[1]

Psocodea

Classification

Phthiraptera is clearly a

paraphyletic and four suborders were then recognized:[30]

Upon finding that Phthiraptera was nested within

phylogenetic research.[2][3]

Nearly 5,000 species of louse have been identified, about 4,000 being parasitic on birds and 800 on mammals. Lice are present on every continent in all the habitats that their host animals occupy.[30] They are found even in the Antarctic, where penguins carry 15 species of lice (in the genera Austrogonoides and Nesiotinus).[31] The oldest known record of the group is Megamenopon rasnitsyni from the Eocene of Germany, but it is essentially a modern form, belonging to Amblycera, so the group as a whole likely has an origin in the Mesozoic.[27]

Phylogeny

Lice have been the subject of significant DNA research in the 2000s that led to discoveries on human evolution. The three species of sucking lice that parasitize human beings belong to two genera, Pediculus and Pthirus: head lice (Pediculus humanus capitis), body lice (Pediculus humanus humanus), and pubic lice (Pthirus pubis). Human head and body lice (genus Pediculus) share a common ancestor with chimpanzee lice, while pubic lice (genus Pthirus) share a common ancestor with gorilla lice. Using phylogenetic and cophylogenetic analysis, Reed et al. hypothesized that Pediculus and Pthirus are sister taxa and monophyletic.[32] In other words, the two genera descended from the same common ancestor. The age of divergence between Pediculus and its common ancestor is estimated to be 6-7 million years ago, which matches the age predicted by chimpanzee-hominid divergence.[32] Because parasites rely on their hosts, host–parasite cospeciation events are likely.

Genetic evidence suggests that human ancestors acquired pubic lice from gorillas approximately 3-4 million years ago.[32] Unlike the genus Pediculus, the divergence in Pthirus does not match the age of host divergence that likely occurred 7 million years ago. Reed et al. propose a Pthirus species host-switch around 3-4 million years ago. While it is difficult to determine if a parasite–host switch occurred in evolutionary history, this explanation is the most parsimonious (containing the fewest evolutionary changes).[32]

Additionally, the DNA differences between head lice and body lice provide corroborating evidence that humans used clothing between 80,000 and 170,000 years ago, before leaving Africa.[33] Human head and body lice occupy distinct ecological zones: head lice live and feed on the scalp, while body lice live on clothing and feed on the body. Because body lice require clothing to survive, the divergence of head and body lice from their common ancestor provides an estimate of the date of introduction of clothing in human evolutionary history.[33][34]

The mitochondrial genome of the human species of the body louse (

Pthirus pubis) fragmented into a number of minichromosomes, at least seven million years ago.[35] Analysis of mitochondrial DNA in human body and hair lice reveals that greater genetic diversity existed in African than in non-African lice.[34][36] Human lice can also shed light on human migratory patterns in prehistory. The dominating theory of anthropologists regarding human migration is the Out of Africa Hypothesis. Genetic diversity accumulates over time, and mutations occur at a relatively constant rate. Because there is more genetic diversity in African lice, the lice and their human hosts must have existed in Africa before anywhere else.[36]

In human culture

For information about human infestation, see
Treatment of human head lice
.

In social history

Drawing of a louse clinging to a human hair. Robert Hooke, Micrographia, 1667

Lice have been intimately associated with human society throughout history. In the

ointment made from pork grease, incense, lead, and aloe.[39]

Robert Hooke's 1667 book, Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses with observations and Inquiries thereupon, illustrated a human louse, drawn as seen down an early microscope.[40]

The Description of a New World, Called The Blazing-World (1668) has "Lice-men" as "mathematicians", investigating nature by trying to weigh the air like the real scientist Robert Boyle.[41][42]

In 1935 the Harvard medical researcher Hans Zinsser wrote the book Rats, Lice and History, alleging that both body and head lice transmit typhus between humans.[43] Despite this, the modern view is that only the body louse can transmit the disease.[44]

Detail showing delousing from Jan Siberechts' painting Cour de ferme ("Farmyard"), 1662

Soldiers in the trenches of the

Auschwitz under the Nazi regime.[45]

In the psychiatric disorder delusional parasitosis, patients express a persistent irrational fear of animals such as lice and mites, imagining that they are continually infested and complaining of itching, with "an unshakable false belief that live organisms are present in the skin".[46]

In science

The human body louse Pediculus humanus humanus has (2010) the smallest insect

vector competence.[48]

In literature and folklore

Mother Louse, a notorious alewife in Oxford during the mid-18th century, shown with three lice as a coat of arms. Image by David Loggan.[49][50]

James Joyce's 1939 book Finnegans Wake has the character Shem the Penman infested with "foxtrotting fleas, the lieabed lice, ... bats in his belfry".[51]

Clifford E. Trafzer's A

Southern Paiute Tribe retells the story of Sinawavi (Coyote)'s love for Poowavi (Louse). Her eggs are sealed in a basket woven by her mother, who gives it to Coyote, instructing him not to open it before he reaches home. Hearing voices coming from it, however, Coyote opens the basket and the people, the world's first human beings, pour out of it in all directions.[52]

The Irish songwriter John Lyons (b. 1934) wrote the popular[53] song The Kilkenny Louse House. The song contains the lines "Well we went up the stairs and we put out the light, Sure in less than five minutes, I had to show fight. For the fleas and the bugs they collected to march, And over me stomach they formed a great arch". It has been recorded by Christie Purcell (1952), Mary Delaney on From Puck to Appleby (2003), and the Dubliners on Double Dubliners (1972) among others.[53][54]

Robert Burns dedicated a poem to the louse, inspired by witnessing one on a lady's bonnet in church: "Ye ugly, creepin, blastid wonner, Detested, shunn'd, by saint and sinner, How dare ye set your fit upon her, sae fine lady! Gae somewhere else, and seek your dinner on some poor body." John Milton in Paradise Lost mentioned the biblical plague of lice visited upon pharaoh: "Frogs, lice, and flies must all his palace fill with loathed intrusion, and filled all the land." John Ray recorded a Scottish proverb, "Gie a beggar a bed and he'll repay you with a Louse." In Shakespeare's Troilus and Cressida, Thersites compares Menelaus, brother of Agamemnon, to a louse: "Ask me not what I would be, if I were not Thersites; for I care not to be the louse of a lazar, so I were not Menelaus."[55]

Woodlouse

The name

suborder Oniscidea within the order Isopoda, unrelated to lice. The Oxford English Dictionary's earliest citation of this usage is from 1611.[56]

See also

References

  1. ^
    PMID 32979270
    .
  2. ^ a b Johnson, Kevin P.; Smith, Vincent S. (2021). "Psocodea species file online, Version 5.0". Retrieved 2021-11-03.
  3. ^ a b "Catalogue of Life, Phthiraptera Haeckel, 1896". 2021. Archived from the original on 2021-11-05. Retrieved 2021-11-03.
  4. ^
    PMID 38320551
    .
  5. ^
    ISBN 978-0-19-510033-4
    .
  6. ISBN 978-0-549-46429-7.{{cite thesis}}: CS1 maint: date and year (link
    )
  7. ^
    ISBN 978-1-4020-6242-1
    .
  8. ISBN 978-1-118-84615-5
    .
  9. ^ Smith V. "Phthiraptera: Summary". Phthiraptera.info. Retrieved 25 October 2015.[permanent dead link]
  10. S2CID 13547569
    .
  11. JSTOR 3676976
    .
  12. JSTOR 3677308
    .
  13. S2CID 31000581
    .
  14. S2CID 38683871
    .
  15. S2CID 12992951
    .
  16. S2CID 11433594
    .
  17. ^
    PMID 8314369
    .
  18. doi:10.1080/106351599260544
    .
  19. PMID 20455925
    .
  20. JSTOR 5727
    .
  21. S2CID 13869042
    .
  22. JSTOR 3283282
    .
  23. S2CID 85731062. Archived from the original
    (PDF) on 2010-06-10. Retrieved 2010-08-14.
  24. doi:10.1093/icb/30.2.251. Archived from the original
    (PDF) on 2010-06-10. Retrieved 2010-08-14.
  25. doi:10.1093/beheco/ari029
    .
  26. PMID 20860811
    .
  27. ^
    PMID 15503987
    .
  28. ^ Rasnitsyn AP, Zherikhin VV (1999). "First fossil chewing louse from the lower Cretaceous of Baissa, Transbaikalia (Insecta, Pediculida= Phthiriaptera, Saurodectidae fam. n.)". Russian Entomological Journal. 8 (4): 253–5.
  29. ISBN 978-3-662-10396-8
    .
  30. ^ a b Smith V. "Phthiraptera.info". International Society of Phthirapterists. Retrieved 25 October 2015.
  31. S2CID 53516244
    .
  32. ^
    PMID 17343749
    .
  33. ^ a b Parry W (7 November 2013). "Lice Reveal Clues to Human Evolution". LiveScience. Retrieved 25 October 2015.
  34. ^
    S2CID 15277254
    .
  35. PMID 23042553
    .
  36. ^
    S2CID 9456340
    .
  37. PMID 19067623
    .
  38. Aeon
    . Retrieved 2022-10-13.
  39. ISBN 978-0-7787-1351-7
    .
  40. ^ Hooke R. "Microscopic view of a louse". The Royal Society. Retrieved 17 October 2015.
  41. ISBN 978-0-8018-9443-5
    . The Bear-men were to be her Experimental Philosophers, the Bird-men her Astronomers, the Fly- Worm- and Fish-men her Natural Philosophers, the Ape-men her Chymists, the Satyrs her Galenick Physicians, the Fox-men her Politicians, the Spider- and Lice-men her Mathematicians, the Jackdaw- Magpie- and Parrot-men her Orators and Logicians, the Gyants her Architects, &c.
  42. ^ Cavendish M (1668). The Description of a New World, Called the Blazing-World. A. Maxwell.
  43. ISBN 978-1-4128-0672-5
    .
  44. ^ Altschuler DZ (1990). "Zinsser, Lice and History". HeadLice.org. Retrieved 19 October 2015.
  45. ^ Evans RJ. "The Great Unwashed". Gresham College. Retrieved 17 October 2015.
  46. ^ Weinstein P (26 February 2013). "'The Great Unwashed': Entomophobia/Delusionary Parasitosis; Illusionary Parasitosis". The Great Plagues: Epidemics in History from the Middle Ages to the Present Day. University of Sydney Department of Medical Entomology. Archived from the original on 17 May 2016. Retrieved 17 October 2015.
  47. PMID 20566863
    .
  48. PMID 21655436
    .
  49. ^ White W (1859). Notes & Queries. Oxford University Press. pp. 275–276.
  50. ^ Pierce H (2004). "Unseemly pictures: political graphic satire in England, c. 1600-c. 1650" (PDF). University of York.
  51. ^ Joyce J (1939). Finnegans Wake. Faber. p. 180.
  52. ISBN 978-0-295-80582-5
    .
  53. ^ a b Carroll J. "Songs of Clare: The Kilkenny Louse House". Clare Library. Retrieved 19 October 2015.
  54. ^ Scott B (2013). "My Colleen by the Shore" (PDF). Veteran. Retrieved 25 October 2015.
  55. hdl:10393/21088
    .
  56. ^ "Woodlouse". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)

External links

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