Amblycera

Amblycera is a parvorder of chewing lice from the infraorder Phthiraptera. The lice are ectoparasites and spend their entire lives parasitizing off of their hosts. Amblycera tend to mostly feed off of 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 hostTemplate:Ndashspecific.

Classification

Amblycera is currently classified as a parvorder, and it was named by Kellogg in 1896.<ref name="PsocodeaSpeciesFile">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Amblycera belongs to the infraorder Phthiraptera, which contains all lice, and is part of the larger order Psocodea, which also contains booklice, barklice and barkflies. Around 30% of all bird lice belong to Amblycera.<ref name=":8">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> A cladogram showing the position of Amblycera within Phthiraptera and Psocodea is shown below:<ref name="deMoya2021">Template:Cite journal</ref> Template:Clade

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.<ref name=":0">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Almost all Amblycera exclusively parasitize birds.<ref name=":0" /> In a section of their throat called the crop, Amblycera contain developed comb structures at the base.<ref name=":1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The structures are used to prevent feathers and other debris from progressing further into the digestive system.<ref name=":1" /> All species are wingless, and have a broad head with a pair of mandibles.<ref name=":2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name=":2" /> Species are small and dorsoventrally compressed, and are host specific in that a single species will parasitize on a single host.<ref name=":0" /> They can vary between one and five millimeters long, and range in color from white to black.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Life cycle

Amblycera undergo a process of metamorphosis with three stages: Eggs (also known as "nits"), nymph and adult. The process usually takes around two to three weeks on average.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Eggs are usually 0.8 millimeters long and oval shaped. The eggs also small holes called micropyles that allow for respiration.<ref>Template:Cite book</ref> They range in color from yellow to white.<ref name=":3">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The nymphs are also yellow to white in color, and undergo a three part process of moulting 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.<ref name=":3" />

Feeding method

Amblycera feed almost entirely on birds. The lice depend on a combination of skin, hair, feathers and blood for food and nutrients.<ref name=":4">Template:Cite journal</ref> 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.<ref name=":4" /> They feed on both living and dead cells, as opposed to the closely related ischnoceran lice that feeds exclusively on dead material.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Amblycera lice tend to parasitize one host before quickly moving onto another one, without staying nearby one that is dead.<ref name=":8" />

Distribution

Like all lice, Amblycera are distributed in the same locations as their preferred host.<ref name=":5">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The lice were likely spread during the original human colonization of various continents when host animals were brought along with them.<ref name=":5" /> The most diverse family, Menoponidae, has a high quantity of host-specific species is distributed across multiple continents.<ref>Template:Cite journal</ref> 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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Effects

The lice by themselves are not particularly harmful,<ref name=":6">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> however depending on the quantity the presence of Amblycera on birds they can cause dermatitis and promote itchiness and scratching.<ref name=":7">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In poultry, the lice can significantly reduce the rate of egg production.<ref name=":7" /> Birds with physically damaged bodies are vulnerable to Amblycera infestations due to the reduced ability to remove the lice by themselves.<ref name=":6" /> Birds infested with Amblycera also have a reduced ability to attract mating partners.<ref name=":7" />

Families

Amblycera contain seven individual families of parasitic lice:<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Menoponidae Mjöberg, 1910
• Laemobothriidae Mjöberg 1910
• Ricinidae Neumann 1890
• Boopiidae Mjöberg, 1910
• Gyropidae Kellogg, 1896
• Trimenoponidae Neumann 1890
• Abrocomophagidae Emerson and Price 1976

References

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