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Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...
s. Phthiraptera has variously been recognized as an
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
, infraorder, or a parvorder, as a result of developments in phylogenetic research. Lice are obligate parasites, living externally on warm-blooded
hosts A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman *Michel Host ...
which include every species of
bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
and
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
, except for monotremes, pangolins, and bats. 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, while 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 The National Institutes of Technology (NITs) are the central government-owned-public technical institutes under the ownership of Ministry of Education, Government of India. They are governed by the National Institutes of Technology, Scienc ...
, 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 Psocoptera are a paraphyletic group of insects that are commonly known as booklice, barklice or barkflies. The name Psocoptera has been replaced with Psocodea in recent literature, with the inclusion of the former order Phthiraptera into Psoco ...
(now called
Psocodea Psocodea is a taxonomic group of insects comprising the bark lice, book lice and parasitic lice. It was formerly considered a superorder, but is now generally considered by entomologists as an order. Despite the greatly differing appearance of ...
), commonly known as booklice, barklice or barkflies. The oldest known fossil lice are from the Paleogene, though
molecular clock The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleo ...
estimates suggest that they originated earlier, during the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
. Humans host two species of louse—the
head louse The head louse (''Pediculus humanus capitis'') is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of ...
and the body louse are subspecies of ''
Pediculus humanus ''Pediculus humanus'' is a species of louse that infects humans. It comprises two subspecies: *''Pediculus humanus humanus'' Linnaeus, 1758 – body louse The body louse (''Pediculus humanus humanus'', also known as ''Pediculus humanus cor ...
''; and the pubic louse, '' Pthirus pubis''. The body louse has the smallest
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
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 In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
. They appear in folktales, songs such as ''The Kilkenny Louse House'', and novels such as
James Joyce James Augustine Aloysius Joyce (2 February 1882 – 13 January 1941) was an Irish novelist, poet, and literary critic. He contributed to the Modernism, modernist avant-garde movement and is regarded as one of the most influential and important ...
'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 sebaceous secretions and body fluids of their host; and chewing lice, which are scavengers, feeding on
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...
, fragments of feathers or hair, and debris found on the host's body. Many lice are specific to a single species of host and have co-evolved with it. In some cases, they live on only a particular part of the body. Some animals are known to host up to fifteen different species, although one to three is typical for mammals, and two to six for birds. Lice generally cannot survive for long if removed from their host. If their host dies, lice can opportunistically use phoresis to hitch a ride on a fly and attempt to find a new host. Sucking lice range in length from . They have narrow heads and oval, flattened bodies. They have no ocelli, and their compound eyes are reduced in size or absent. Their antennae are short with three to five segments, and their mouthparts, which are retractable into their head, are adapted for piercing and sucking. There is a cibarial pump at the start of the gut; it is powered by muscles attached to the inside of the cuticle of the head. The mouthparts consist of a proboscis which is toothed, and a set of stylets arranged in a cylinder inside the proboscis, containing a salivary canal ( ventrally) and a food canal ( dorsally). 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. Chewing lice are also flattened and can be slightly larger than sucking lice, ranging in length from . 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 The Ischnocera is a large superfamily of lice. They are mostly parasitic on birds, but including a large family (the Trichodectidae) parasitic on mammals. The genus '' Trichophilopterus'' is also found on mammals (lemurs), but probably belong ...
, but club-shaped in the suborder
Amblycera The Amblycera are a large clade of chewing lice, parasitic on both birds and mammals. The Amblycera are considered the most primitive clade of lice. Description These insects are very much like the familiar advanced sucking lice, except th ...
. 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. 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 Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...
, 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. 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. Humans host three different kinds of lice: head lice, body lice, and
pubic lice Pediculosis pubis (also known as "crabs" and "pubic lice") is an infestation by the pubic louse, ''Pthirus pubis'', a wingless insect which feeds on blood and lays its eggs (nits) on mainly pubic hair. Less commonly, hair near the anus, armpi ...
. Head lice and body lice are subspecies of ''Pediculus humanus'', and pubic lice are a separate species, ''Pthirus pubis''. Lice infestations can be controlled with lice combs, and medicated shampoos or washes.


Ecology

The average number of lice per host tends to be higher in large-bodied bird species than in small ones. 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. Host organisms that dive under water to feed on aquatic prey harbor fewer taxa of lice. 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. Reductions in the size of host populations may cause a long-lasting reduction of louse taxonomic richness, for example, birds introduced into
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
host fewer species of lice there than in Europe. 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. 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. Lice may reduce host life expectancy if the infestation is heavy, but most seem to have little effect on their host. The habit of dust bathing in domestic hens is probably an attempt by the birds to rid themselves of lice. Lice may transmit microbial diseases and helminth parasites, but most individuals spend their whole life cycle on a single host and are only able to transfer to a new host opportunistically. Ischnoceran lice may reduce the
thermoregulation Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperatur ...
effect of the plumage; thus heavily infested birds lose more heat than others. Lice infestation is a disadvantage in the context of sexual rivalry.


Evolution

Phthiraptera lice are members of
Psocodea Psocodea is a taxonomic group of insects comprising the bark lice, book lice and parasitic lice. It was formerly considered a superorder, but is now generally considered by entomologists as an order. Despite the greatly differing appearance of ...
(formerly
Psocoptera Psocoptera are a paraphyletic group of insects that are commonly known as booklice, barklice or barkflies. The name Psocoptera has been replaced with Psocodea in recent literature, with the inclusion of the former order Phthiraptera into Psoco ...
), the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
that contains booklice, barklice and barkflies. Within Psocodea, lice are within the suborder Troctomorpha, and most closely related to the family Liposcelididae. The oldest confirmed fossil louse is a bird louse, '' Megamenopon rasnitsyni'', from Eckfelder Maar, Germany, which dates to the
Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...
, around 44 million years ago. '' Saurodectes vrsanskyi'' from the Early Cretaceous ( Aptian) Zaza Formation of Buryatia, Russia, has also been suggested to be a louse, but this is tentative. Cladogram showing the position of Phthiraptera within
Psocodea Psocodea is a taxonomic group of insects comprising the bark lice, book lice and parasitic lice. It was formerly considered a superorder, but is now generally considered by entomologists as an order. Despite the greatly differing appearance of ...
:


Classification

Phthiraptera is clearly a monophyletic grouping, united as the members are by a number of derived features including their parasitism on
warm-blooded Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The on ...
vertebrates and the combination of their metathoracic ganglia with their abdominal ganglia to form a single ventral nerve junction. The order has traditionally been divided into two suborders, the sucking lice (Anoplura) and the chewing lice (Mallophaga); however, subsequent classifications suggest that the Mallophaga are
paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...
and four suborders were then recognized: *
Anoplura Sucking lice (Anoplura, formerly known as Siphunculata) have around 500 species and represent the smaller of the two traditional superfamilies of lice. As opposed to the paraphyletic chewing lice, which are now divided among three suborders, t ...
: sucking lice, occurring on mammals exclusively * Rhynchophthirina: parasites of elephants and
warthog ''Phacochoerus'' is a genus in the family Suidae, commonly known as warthogs (pronounced ''wart-hog''). They are pigs who live in open and semi-open habitats, even in quite arid regions, in sub-Saharan Africa. The two species were formerly con ...
s *
Ischnocera The Ischnocera is a large superfamily of lice. They are mostly parasitic on birds, but including a large family (the Trichodectidae) parasitic on mammals. The genus '' Trichophilopterus'' is also found on mammals (lemurs), but probably belong ...
: mostly avian chewing lice, with one family parasitizing mammals *
Amblycera The Amblycera are a large clade of chewing lice, parasitic on both birds and mammals. The Amblycera are considered the most primitive clade of lice. Description These insects are very much like the familiar advanced sucking lice, except th ...
: a primitive suborder of chewing lice, widespread on birds, and also occurring on South American and Australian mammals Upon finding that Phthiraptera was nested within
Psocoptera Psocoptera are a paraphyletic group of insects that are commonly known as booklice, barklice or barkflies. The name Psocoptera has been replaced with Psocodea in recent literature, with the inclusion of the former order Phthiraptera into Psoco ...
, Phthiraptera, in 2021 de Moya et al. proposed reducing the rank of Phthiraptera to infraorder, and the four suborders to parvorder. These changes were accepted by Psocodea Species File and others, with the exception of placing Phthiraptera under the infraorder Nanopsocetae, as a parvorder, with the four subgroups listed above. These classifications are likely to change in the future as a result of ongoing
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
research. 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. They are found even in the Antarctic, where
penguin Penguins (order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adap ...
s carry 15 species of lice (in the genera '' Austrogonoides'' and '' Nesiotinus''). 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. File:Ricinus bombycillae (Denny, 1842).JPG, ''Ricinus bombycillae'', an amblyceran louse from a Bohemian waxwing File:Trinoton anserinum (Fabricius, 1805).JPG, ''Trinoton anserinum'', an amblyceran louse from a mute swan File:Lice image01.jpg, '' Bovicola limbata'', an ischnoceran louse from
goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
s. The species is sexually dimorphic, with the male smaller than the female.


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. 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. Because parasites rely on their hosts, hostparasite cospeciation events are likely. Genetic evidence suggests that human ancestors acquired pubic lice from
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four ...
s approximately 3-4 million years ago. 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 parasitehost switch occurred in evolutionary history, this explanation is the most parsimonious (containing the fewest evolutionary changes). 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. 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. The mitochondrial genome of the human species of the body louse (''
Pediculus humanus humanus The body louse (''Pediculus humanus humanus'', also known as ''Pediculus humanus corporis'') is a hematophagic ectoparasite louse that infests humans. It is one of three lice which infest humans, the other two being the head louse, and the cra ...
''), the head louse (''
Pediculus humanus capitis The head louse (''Pediculus humanus capitis'') is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of ...
'') and the pubic louse ('' Pthirus pubis'') fragmented into a number of minichromosomes, at least seven million years ago. Analysis of mitochondrial DNA in human body and hair lice reveals that greater genetic diversity existed in African than in non-African lice. 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.


In human culture


In social history

Lice have been intimately associated with human society throughout history. In the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
, they were essentially ubiquitous. At the death of
Thomas Becket Thomas Becket (), also known as Saint Thomas of Canterbury, Thomas of London and later Thomas à Becket (21 December 1119 or 1120 – 29 December 1170), was an English nobleman who served as Lord Chancellor from 1155 to 1162, and the ...
, Archbishop of Canterbury in 1170, it was recorded that "The vermin boiled over like water in a simmering cauldron, and the onlookers burst into alternate weeping and laughing". The clergy often saw lice and other parasites as a constant reminder of human frailty and weakness. Monks and nuns would purposely ignore grooming themselves and suffer from infestations to express their religious devotion. A mediaeval treatment for lice was an ointment made from pork grease,
incense Incense is aromatic biotic material that releases fragrant smoke when burnt. The term is used for either the material or the aroma. Incense is used for aesthetic reasons, religious worship, aromatherapy, meditation, and ceremony. It may also b ...
,
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...
, and aloe. 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 A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisi ...
. Margaret Cavendish's satirical '' 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 Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, alchemist and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders ...
. In 1935 the Harvard medical researcher Hans Zinsser wrote the book ''
Rats, Lice and History ''Rats, Lice and History'' is a 1935 book written by biologist Hans Zinsser on the subject of typhus, a disease on which he performed significant research. Zinsser frames the book as a biography of the infectious disease, tracing its path through ...
'', alleging that both body and head lice transmit typhus between humans. Despite this, the modern view is that only the body louse can transmit the disease. Soldiers in the trenches of the
First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...
suffered severely from lice, and the typhus they carried. The Germans boasted that they had lice under effective control, but themselves suffered badly from lice in the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
on the Eastern Front, especially in the Battle of Stalingrad. " Delousing" became a
euphemism A euphemism () is an innocuous word or expression used in place of one that is deemed offensive or suggests something unpleasant. Some euphemisms are intended to amuse, while others use bland, inoffensive terms for concepts that the user wishes ...
for the extermination of Jews in concentration camps such as Auschwitz under the Nazi regime. 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".


In science

The human body louse ''Pediculus humanus humanus'' has (2010) the smallest insect
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
known. This louse can transmit certain diseases while the human head louse (''P. h. capitis''), to which it is closely related, cannot. With their simple life history and small genomes, the pair make ideal model organisms to study the molecular mechanisms behind the transmission of
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a g ...
s and vector competence.


In literature and folklore

James Joyce James Augustine Aloysius Joyce (2 February 1882 – 13 January 1941) was an Irish novelist, poet, and literary critic. He contributed to the Modernism, modernist avant-garde movement and is regarded as one of the most influential and important ...
's 1939 book '' Finnegans Wake'' has the character Shem the Penman infested with " foxtrotting fleas, the lieabed lice, ... bats in his belfry". Clifford E. Trafzer's ''A
Chemehuevi The Chemehuevi are an indigenous people of the Great Basin. They are the southernmost branch of Southern Paiute.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. The Irish songwriter John Lyons (b. 1934) wrote the popular 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. 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 William Shakespeare ( 26 April 1564 – 23 April 1616) was an English playwright, poet and actor. He is widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's nation ...
's ''
Troilus and Cressida ''Troilus and Cressida'' ( or ) is a play by William Shakespeare, probably written in 1602. At Troy during the Trojan War, Troilus and Cressida begin a love affair. Cressida is forced to leave Troy to join her father in the Greek camp. Me ...
'', Thersites compares
Menelaus In Greek mythology, Menelaus (; grc-gre, Μενέλαος , 'wrath of the people', ) was a king of Mycenaean (pre- Dorian) Sparta. According to the ''Iliad'', Menelaus was a central figure in the Trojan War, leading the Spartan contingent of ...
, 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."


See also

*
Pest (organism) A pest is any animal or plant harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environ ...
* Use of DNA in forensic entomology


References


External links


National Pesticide Information Center – Understanding and Controlling Lice
on the
University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...
/
Institute of Food and Agricultural Sciences The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is a teaching, research and Extension scientific organization focused on agriculture and natural resources. It is a partnership of federal, state, and county governmen ...
Featured Creatures Web site
crab louse
on the
University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...
/
Institute of Food and Agricultural Sciences The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is a teaching, research and Extension scientific organization focused on agriculture and natural resources. It is a partnership of federal, state, and county governmen ...
Featured Creatures Web site
''Pediculus humanus capitis'' head louse facts, myths, life cycle at MetaPathogen

Parasitic Insects, Mites and Ticks: Genera of Medical and Veterinary Importance
Wikibooks {{Authority control Insects in culture Taxa named by Ernst Haeckel Delusional parasitosis Nanopsocetae