File: <mallophaga

Mallophaga, or "bird lice" or "chewing lice" are exclusively ectoparasites of birds and occasionally of mammals. Their reduced eyes, flattened form and tarsal claws are correlated with this mode of life. Unlike the Anoplura they have no piercing mouthparts and consume with well-developed chewing mouthparts small particles of feathers, hair, or other cuticular matter. They have been known to draw some blood from chickens.

All species are apterous, although it is believed that they lost wings in evolution, which is evidenced from thoracic sclerites. There is a gradual metamorphosis. The various families of biting lice are confined to definite groups of birds, indicating that evolution of the parasites has proceeded along with that of their bird hosts.

The common hen-louse, Menoponpallidum is an example. The head is semicircular in form and articulates with a prothorax that is freely movable on the rest of the body. A tagma is formed by the fusion of the meso- and metathorax with the abdomen. The mouth is situated ventrally on the head and surrounded by biting mandibles and less prominent 1st and 2nd maxillae.

Occurrence & Habits

All stages occur on the host and reproduction is continuous. Although birds are the primary hosts Mallophaga are also found on mammals occasionally. Birds that have become infested often exhibit the habit of "dusting", which cuts down on the number of lice. High infestations will cause a loss of weight and lowering of egg production in fowl, whereas small birds are often killed. Humans are never attacked.

When Mallophaga occur on birds they possess two claws, while on mammals only one claw is present.

Eggs are laid separately on feathers or hairs and the life cycle is completed in about a month, the young instars resembling the adult in form and habit. They are spread very rapidly through bodily contact. They crawl on the ground during the day and return to their host at night.

Control of Mallophaga

Mallophaga used to be controlled by dusting their poultry hosts with insecticides. Restrictions on such practices for public health reasons have made it exceedingly difficult to control these insects. When poultry are raised for the production of eggs and meat it is best to corral them in open fenced yards on the ground. In this way the birds are able to dust themselves with soil and thereby reduce louse infestations significantly. Such operations are not always economically practical, however, because of the additional space required and the difficulty of harvesting their eggs.

Details of Insect Taxonomic Groups

Examples of beneficial species occur in almost every insect order, and considerable information on morphology and habits has been assembled. Therefore, the principal groups of insect parasitoids and predators provide details that refer to the entire class Insecta. These details are available at <taxnames.htm>.

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References

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