Pyroglyphidae is a family of non-parasitic

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

s. It includes the house dust mite that live in human dwellings, many species that live in the burrows and nests of other animals, and some pests of dried products stored in humid conditions.

Etymology

The naming of the family originates from the fact that

dust mites House dust mites (HDM, or simply dust mites) are various species of acariform mites belonging to the family Pyroglyphidae that are found in association with dust in dwellings. They are known for causing allergies. Biology Species The current ...

cause

eczema Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...

, with intense itching and a red rash. The condition has been described as like burns from fire on the skin, with a 'burning' itching sensation, hence the word 'Pyro' in 'pyroglyphidae'.

Characteristics

Mites in this family are very tiny; the female American house dust mite (''Dermatophagoides farinae''), for example, measures about 420 microns in length and 320 microns in width, with the male being somewhat narrower.

Ecology

These mites mostly live in the nests and burrows of animals and birds where they feed on

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

from the skin and feathers of their hosts. They need a humid atmosphere because the air is their only source of moisture. They thrive when the

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

is greater than 50% but become desiccated and die at lower relative humidity levels. Other mites in this family feed on stored products such as grain, cereals, nuts, dried fruit, cheeses and pet foods, but only in conditions of high relative humidity. The sexes are separate in this family. The female lays two or three eggs each day and these develop through several stages;

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

, protonymph, trytonymph and adult. At , the complete cycle takes 34 days, but the length of time taken varies with the temperature and relative humidity. If the latter is very low, the protonymph can enter

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

, surviving for several months in a quiescent state until conditions improve, after which development recommences.

House dust mites

Three species of house dust mite are commonly found in human dwellings; ''Dermatophagoides farinae'', ''Dermatophagoides pteronyssinus'' and ''Euroglyphus maynei''. They feed on flakes of skin found in dust and typically occur on carpets, around sofas and chairs, and on mattresses. They may be very plentiful in the humid tropics, but in temperate climates are more numerous in humid summers than in winters, when the relative humidity is usually lower in homes. Some people suffer a reaction to

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms ...

s present in the faeces of

house dust mites House dust mites (HDM, or simply dust mites) are various species of acariform mites belonging to the family Pyroglyphidae that are found in association with dust in dwellings. They are known for causing allergies. Biology Species The current ...

. These may cause

atopic dermatitis Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin (dermatitis). It results in puritis, itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens o ...

or be inhaled giving rise to

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, cou ...

or rhinitis.

References

External links

* * {{Taxonbar, from=Q7263653 Acariformes Acari families