Acari

SEM image of Ella Tucker sp. a parasite of tropical citrus plants, at 260 -fold magnification ( later colored for illustration)

Mites ( Acari ) are a subclass of arachnids (Arachnida ) in the family of arthropods. Mites With about 50,000 known species in 546 families, the most species-rich group of arachnids. As to them, the smallest arthropods ( Arthropoda ) belong, it can be assumed that many species have not yet been discovered.

Features

While spiders live exclusively predatory and all broadly have a similar physique to mites differ due to their different way of life with each other much more. The smallest mites are only about 0.1 millimeters. The largest are ticks, in which the females when saturated up to three inches may be large. Like spiders, they have eight legs, although they often have only six legs in the larval stage.

Since mites in absolute terms are not particularly fast, use some of them other animals such as insects as transport ( see Phoresy ) to travel longer distances. Here, suck some mites during the ride up body fluids of their host.

A tropical Hornmilbenart ( Archegozetes longisetosus ) is considered in relation to their body size of 0.8 mm, the strongest animal in the world: you can keep almost the 1200 times its own body weight, about five times more than would be expected theoretically ( Heethoff & Koerner 2007).

While there are mite species that use a sight to hunt live prey, yet the individuals of many other species of mites are characterized by blindness. The central eyes of arachnids mites are in general not exist, or they are merged into a single eye. In general, one can at mites animals find one number from zero to five.

Occurrence

Mites have colonized many habitats. About half of the known species live in the soil, which in good conditions find a few hundred thousand mites per square meter of space and food. Among the habitats, however, are also so unusual, such as monkeys lungs, nostrils of birds and Tracheenöffnungen of insects. Also, most people harbor mites, for example, in hair follicles of the eyelashes.

Nutrition

In addition to the predatory mites, there are those that feed on plants and fungi, and still others that live on carrion or dead tissue. There are also among the many mite parasites.

Harmful effect

Pests in agriculture

Although most of the species live in the soil and there makes a significant contribution to the formation of humus, some species of mites can be viewed as an authoritative yet agricultural pests. They can occur as pests in flour or grain storage. The flour mite ( Acarus siro ) can change their infestation by the ingredients, also it is often perceived as disgusting. In general, let mites because of their resistance to pesticides is difficult to combat. Therefore, the research has recently begun on alternative methods. An attempt is made to alter the composition of the bacteria in the interior of the mites, thereby reducing their resistance.

Mites cause illness

Diseases caused by mites are called Acariose.

Due to the secretions of the house dust mite allergies can be triggered, developed as a consequence, much of the house dust allergen after some time without treatment of asthma in humans.

Grave mites drill programs in the skin of their host and lay their eggs. This causes intense itching in the individual patient. The hatching from the eggs, larvae produce the clinical picture of scabies in animals, the scabies in humans.

Haarbalgmilben ( genus Demodex ) live in the hair follicles of mammals. Demodex canis lives in the skin of many dogs, but only in dogs with a weakened immune system of it comes through it to a typical skin disease. Demodex folliculorum is found in all humans as a harmless inhabitant of the hair follicles and skin residents, where it feeds mainly of fat, but also bacteria. Suspected but unproven is associated with rosacea.

Feather mites parasitize on or in the feathers of birds.

Different types of mites ( Trombiculidae ) can also cause the Trombidiose ( harvest scabies) in humans.

In honeybees some mites such as Varroa mite animal diseases evoke ( Varroose, Acarapidose, Tropilaelapsose ).

Mites as carriers of disease

Some species of mites can be transmitted through their bite spotted fever, Rickettsipocken, tularemia, and St. Louis encephalitis. The representatives of the suborder ticks can at Bloodsucking dangerous diseases such as viral meningitis ( TBE ), transferred Crimean-Congo fever, typhus fever or Lyme disease.

Net effect

Many predatory mites also be classified as beneficial insects because they control pests in agriculture and horticulture. To this end, they are grown in greenhouses under controlled conditions. Use of mites ( Thyroplyphus siro, former name Tyroglyphus casei ) as farm animals takes place in the production of cheese mites.

System

Types (selection)

Alaskozetes antarcticus
Grave mites
Haarbalgmilbe
Dust mites
Autumn grass mites or harvest mites ( Neotrombicula autumnalis )
Histiostomatidae
Horn mite ( Archegozetes longisetosus )
Hörnchengallmilbe or Ahorngallmilbe ( Aceria macrorhyncha )
Johannisbeergallmilbe or Johannisbeerknospengallmilbe ( Cecidophyopsis ribis )
Beetle mite ( Parasitus fucorum / coleoptratorum )
Flour mite
Anthrax - mite
Shell cancer mite
Red Samtmilbe, Sammetmilbe ( Trombidium holosericeum )
Runes mite
Spider mites, red spider ( Metatetranychus ulmi )
Water mite ( Hydrodroma spec.)
Pond mite
Tropical rat mite ( Ornithonyssus bacoti )
Varroa mite
Bird Mites: Red Mite, Nordic Mite
Large onion skin mite ( Rhizoglyphus echinops )
Small onion skin mite ( Tarsonemus laticeps )

Fossil evidence

Mites are not rare in tertiary Bernstein (including Baltic amber, Dominican amber ). Older documents are, however, extremely rare and have, until recently, from the Mesozoic completely. The mite Protacarus crani from the Scottish Devon is the oldest fossil of this taxon and at the same time as the only proof of a mite from the Paleozoic. In 2012, two specimens have been discovered in 230 million years old Triassic amber from the Italian Dolomites. The two dissimilar to the gall mites ( Eriophyidae ) belonging fossils were named by its discoverer David Grimaldi (American Museum of Natural History, New York ) Triasacarus fedelei and Ampezzoa triassica. The fossil forms differ usually only slightly from their recent relatives, so Paläozoologen assume a stagnant early evolution of the mites.

Control agents

Acaricide for the control of mites and ticks.

Sarcoptes Acarapis woodi Saint Louis encephalitis Virus Opilioacaridae Oribatida Anthrax mite Devonian Digital Object Identifier

26889