Amblycera is a

parvorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

of chewing lice from the

infraorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classific ...

Phthiraptera Louse (: lice) is the common name for any member of the infraorder Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera was previously recognized as an order, until a 2021 genetic study determined that ...

. The lice are

ectoparasites Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...

and spend their entire lives parasitizing their hosts. Amblycera tend to mostly feed on birds, and have specialized anatomy to assist in feeding. The lice undergo a three part process of metamorphosis and survive around thirty days after moulting into an adult. They rely on a combination of skin debris and blood for nutrients to sustain themselves. Amblycera are distributed globally, and are very host–specific.

Classification

Amblycera is currently classified as a

, and it was named by Kellogg in 1896. Amblycera belongs to the

, which contains all lice, and is part of the larger

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

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 ...

, which also contains booklice, barklice and barkflies. Around 30% of all bird lice belong to Amblycera. A

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

showing the position of Amblycera within

and

is shown below:

Characteristics

Like all chewing lice, Amblycera are permanent ectoparasites of their hosts, in that they spend their entire life living off of their individual host. Almost all Amblycera exclusively parasitize

birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

. In a section of their throat called the

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. In other words, a crop is a plant or plant product that is grown for a specific purpose such as food, Fiber, fibre, or fuel. When plants of the same spe ...

, Amblycera contain developed comb structures at the base. The structures are used to prevent feathers and other debris from progressing further into the digestive system. All species are wingless, and have a broad head with a pair of mandibles. The antennae are broken into three to five joints depending on the species, and they do not have any eyes. Anmblycera also have two small segmented claws at the end of their limbs. Species are small and dorsoventrally compressed, and are host specific in that a single species will parasitize on a single host. They can vary between one and five millimeters long, and range in color from white to black.

Life cycle

Amblycera undergo a process of

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

with three stages: Eggs (also known as "nits"), nymph and adult. The process usually takes around two to three weeks on average. Eggs are usually 0.8 millimeters long and oval shaped. The eggs also small holes called micropyles that allow for respiration. They range in color from yellow to white. The nymphs are also yellow to white in color, and undergo a three part process of

moulting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at ...

over the course of a week. After the third nymph moult the lice are considered adults, and will live up to thirty days off of their chosen host.

Feeding method

Amblycera feed almost entirely on birds. The lice depend on a combination of skin, hair, feathers and blood for food and nutrients. They use their mandibles in a horizontal scraping fashion to separate the skin from the bird so that it can be consumed. They also use their claws to grasp onto the feathers of the host in order to prevent the bird from shaking the lice off. They feed on both living and dead cells, as opposed to the closely related ischnoceran lice that feeds exclusively on dead material. While most ampblyceran lice use mandibles to feed, species in the genus ''Trochiloecete'' use two sharp stylets to pierce the skin and consume blood from nearby

blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...

. Amblycera lice tend to parasitize one host before quickly moving onto another one, without staying nearby one that is dead.

Distribution

Like all lice, Amblycera are distributed in the same locations as their preferred host. The lice were likely spread during the original human

colonization 475px, Map of the year each country achieved List of sovereign states by date of formation, independence. Colonization (British English: colonisation) is a process of establishing occupation of or control over foreign territories or peoples f ...

of various continents when host animals were brought along with them. The most diverse family, Menoponidae, has a high quantity of host-specific species is distributed across multiple continents. Amblycera have shown a positive correlation between the quantity and diversity of host birds in regions and the quantity and diversity of their own species.

Effects

The lice by themselves are not particularly harmful, however depending on the quantity the presence of Amblycera on birds they can cause

dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

and promote itchiness and scratching. In poultry, the lice can significantly reduce the rate of egg production. Birds with physically damaged bodies are vulnerable to Amblycera infestations due to the reduced ability to remove the lice by themselves. Birds infested with Amblycera also have a reduced ability to attract mating partners.

Families

Amblycera contain seven individual families of parasitic lice: * Menoponidae Mjöberg, 1910 * Laemobothriidae Mjöberg 1910 * Ricinidae Neumann 1890 * Boopiidae Mjöberg, 1910 * Gyropidae Kellogg, 1896 * Trimenoponidae Neumann 1890 * Abrocomophagidae Emerson and Price 1976

References

* * {{Taxonbar, from=Q1936744 Lice