| Phthiraptera | |
|---|---|
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| Light micrograph of Fahrenholzia pinnata | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Subclass: | Pterygota |
| Infraclass: | Neoptera |
| Order: | Phthiraptera Haeckel, 1896 |
| Suborders | |
Lice (singular: louse), also known as fly babies, is the common name for over 3000 species of wingless insects of the order Phthiraptera; three of which are classified as human disease agents. They are obligate ectoparasites of every avian and mammalian order except for Monotremes (the platypus and echidnas), bats, whales, dolphins, porpoises and pangolins.
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Most lice are scavengers, feeding on skin and other debris found on the host's body, but some species feed on sebaceous secretions and blood. Most are found only on specific types of animal, and, in some cases, only to 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. For example, in humans, different species of louse inhabit the scalp and pubic hair. Lice generally cannot survive for long if removed from their host.[1]
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 the males, and some species are even known to be parthenogenetic. A louse's egg is commonly called a nit. Many lice attach their eggs to their host's 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 lice eggs tend to be pale white. Dead lice eggs are more yellow.[1]
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, which they usually reach within a month of hatching.[1]
The order has traditionally been divided into two suborders, the sucking lice (Anoplura) and the chewing lice (Mallophaga); however, recent classifications suggest that the Mallophaga are paraphyletic and four suborders are now recognised:
It has been suggested that the order is contained by the Troctomorpha suborder of Psocoptera.
Humans host three different kinds of lice: head lice, body lice , and pubic lice. The DNA differences between head lice and body lice provide corroborating evidence that humans started losing body hair about 2,000,000 years ago.[2]
Recent DNA evidence suggests that pubic lice spread to humans approximately 2,000,000 years ago from gorillas.[3]
Adult and nymphal lice can survive on sheep-shearers' moccasins for up to 10 days, but microwaving the footwear for five minutes in a plastic bag will kill the lice.[4]
Lice infestations can be controlled with lice combs, and medicated shampoos or washes.
 Ricinus bombycillae, an Amblyceran louse from the bohemian waxwing |
 Trinoton anserinum, an Amblyceran louse from a mute swan. |
 Damalinia limbata is an Ischnoceran louse from goats. The male is smaller than the female. |
 Diagram of a louse, by Robert Hooke, 1667. |
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| Phthiraptera | |||||||||||||
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| File:Fahrenholzia | |||||||||||||
| Fahrenholzia pinnata | |||||||||||||
| Scientific classification | |||||||||||||
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Lice (singular: louse), are wingless insects of the Order Phthiraptera. They are all external parasites, on every species of birds and most mammalian orders. They are not found on Monotremes (the platypus and the echidnas or spiny anteaters) and a few eutherian orders, namely the bats (Chiroptera), whales, dolphins and porpoises (Cetacea) and pangolins (Pholidota). There are more than 3,000 different species; three are classified as human lice.
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Lice spend their whole life on the host. For are adapted to keep close contact with the host. These adaptations are reflected in their size (0.5–8 mm), stout legs, and claws which are adapted to clinging tightly to hair, fur and feathers. They are also wingless and flattened.
Lice feed on skin (epidermal) debris, feather parts, sebaceous secretions and blood. A louse's color varies from pale beige to dark grey; however, if feeding on blood, it may become considerably darker.
A louse's egg is commonly called a nit. Lice attach their eggs to their host's hair with specialized saliva which results in a bond that is very difficult to separate without specialized products. Living lice eggs tend to be pale white. Dead lice eggs are more yellow. Lice are very annoying and are difficult to remove, but not impossible. The process is called nit-picking, and is often done with a close-toothed metal comb. For humans, anti-insect shampoos are available.
The order has traditionally been divided into two suborders; the sucking lice (Anoplura) and chewing lice (Mallophaga). Four suborders are now recognised:
It has been suggested that the order is contained by the Troctomorpha suborder of Psocoptera. What this means is that lice may have evolved from free-living species of that group.
Humans are unique in that they host three different species of lice: head lice, body lice (which live mainly in clothing), and pubic lice. The DNA differences between head lice and body lice provide corroborating evidence that humans started wearing clothes at approximately 70,000 BCE.[1]
Recent DNA evidence suggests that pubic lice spread to the ancestors of humans approximately 3.3 million years ago from the ancestors of gorillas by sharing the same bed or other communal areas with them, and are more closely related to lice endemic to gorillas than to other lice species infesting humans.[2]
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Lice
The chewing louse Damalinia limbata is found on Angora goats. The male louse (right) is typically smaller than the female (left), whose posterior margin of the abdomen is more rounded than those of male lice. |
Louse diagram, Micrographia, Robert Hooke,
Diagram of a louse, by Robert Hooke, 1667. |
Trichodectes
Trichodectes canis, the biting dog louse |
  | Body and Head lice - body louse and head louse, Pediculus spp. |
| | Crab Louse - crab louse, Pthirus pubis (Linnaeus) |
| | Lice Pest Control Information - National Pesticide Information Center - National Pesticide Information Center - Pest Control Information |
| | WebMD Lice Info - Head Lice | Pubic Lice | Body Lice - Symptoms, Diagnosis and Treatment from WebMD |
| | How to Get Rid of Lice - How to Get Rid of Lice - wikiHow |
| | How to Get Rid of Lice - How to Get Rid of Lice - HowToGetRidofStuff.com |
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