name = Mite|
image_width = 200px
image_caption = Peacock mite, "
subclassis = Acari
subclassis_authority = Leach, 1817
and see text
Acarina or Acari are a
taxonof arachnidsthat contains mites and ticks. The diversity of the Acari is extraordinary and its fossil history goes back to the Devonianera. As a result, acarologists (the people who study mites and ticks) have proposed a complex set of taxonomic ranks to classify mites. In most modern treatments, the Acari is considered a subclassof Arachnida and is composed of 2-3 superorders or orders: Acariformes, Parasitiformes, and Opilioacariformes; the latter is often considered a subgroup within the Parasitiformes. The monophylyof the Acari is open to debate and the relationships of the acarines to other arachnids is not at all clear. In older treatments the subgroups of the Acarina were placed at order rank, but as their own subdivisions have become better-understood it is more usual to treat them at superorder rank
Most acarines are minute to small (e.g. 0.08–1.0 mm), but the largest Acari (some ticks and red velvet mites) may reach lengths of 10–20 mm. It is estimated that over 50,000 species have been described (as of 1999) and that a million or more species are currently living. The study of mites and ticks is called acarology (from Greek ἀκάρι, "akari", a type of mite; and -λογία, "-logia")cite book |author=D. E. Walter & H. C. Proctor |year=1999 |title=Mites: Ecology, Evolution and Behaviour |publisher=University of NSW Press, Sydney and CABI, Wallingford |id=ISBN 0-86840-529-9] , and the leading
scientific journals for acarology include " Acarologia", " Experimental and Applied Acarology" and " International Journal of Acarology".
Mites are members of
Arachnidaand, as such, should have a segmented body with the segments organised into two tagmata: a prosoma(cephalothorax) and an opisthosoma(abdomen). However, only the faintest traces of primary segmentation remain in mites, the prosoma and opisthosoma are insensibly fused, and a region of flexible cuticle (the cirumcapitular furrow) separates the chelicerae and pedipalps from the rest of the body. This anterior body region is called the capitulum or gnathosoma and is also found in the Ricinulei. The remainder of the body is called the idiosoma and is unique to mites.
Most adult mites have four pairs of legs, like other
arachnids, but some have fewer. For example, gall mites like "Phyllocoptes variabilis" (superfamily Eriophyioidea) have a wormlike body with only two pairs of legs; some parasitic mites have only one or three pairs of legs in the adult stage. Larval and prelarval stages have a maximum of three pairs of legs; adult mites with only three pairs of legs may be called 'larviform'.
The mouth parts of mites may be adapted for biting, stinging, sawing or sucking. They breath through tracheae, stigmata (small openings of the skin), intestines and the skin itself. Species hunting for other mites have very acute senses, but many mites are eyeless. The central eyes of arachnids are always missing, or they are fused into a single eye. Thus, any eye number from none to five may occurSchmidt 1993: 58ff] .
ontogenytypically consists of an egg, a prelarval stage (often absent), a larval stage (hexapod except in Eriophyoidea which have only two pairs of legs), and a series of nymphal stages. Any or all of these stages except the adult may be suppressed or occur only within the body of a previous stage. Larvae (and prelarvae) have a maximum of three pairs of legs (legs are often reduced to stubs or absent in prelarvae); legs IV are added at the first nymphal stage. Usually a maximum of three nymphal stages are present and they are referred to in sequence as protonymph, deutonymph, and tritonymph; however, some soft ticks have supernumary nymphal stages. The females of some Tarsonemidaebear sexually mature young. If one or more nymphal stages are absent, then authors may disagree on which stage(s) is(are) present. Only the Oribatidapass through all developmental stages.
Diversity and lifestyles
Acarines are extremely diverse. They live in practically every habitat, and include aquatic (freshwater and sea water) and terrestrial species. They outnumber other
arthropodsin the soil organic matter and detritus. Many are parasitic, and they affect both vertebratesand invertebrates. Most parasitic forms are external parasites, while the free living forms are generally predatory and may even be used to control undesirable arthropods. Others are detritivores that help to break down forest litter and dead organic matter such as skincells. Others still are plant feeders and may damage crops.
Damage to crops is perhaps the most costly economic effect of mites, especially by the
spider mites and their relatives (Tetranychoidea), earth mites ( Penthaleidae), thread-footed mites ( Tarsonemidae) and the gall and rust mites ( Eriophyidae). Some parasitic forms affect humansand other mammals, causing damage by their feeding, and can even be vectors of diseasessuch as scrub typhusand rickettsialpox. A well known effect of mites on humans is their role as an allergenand the stimulation of asthmain people affected by respiratory disease. The use of predatory mites (e.g. Phytoseiidae) in pest controland herbivorous mites that infest weeds are also of importance. An unquantified, but major positive contribution of the Acari is their normal functioning in ecosystems, especially their roles in the decomposer subsystem .
phylogenyof the Acari is still disputed and several taxonomic schemes have been proposed for their classification. Most researchers agree that the Acari contain two separate lineages: the Acariformes (also Actinotrichida) and the Parasitiformes (also Anactinotrichida). However, some researchers treat these groups as superorders and others as orders.
Acariformesare the most diverse group of mites.
Trombidiformes- plant parasitic mites (spider mites, peacock mites, gall mites, red-legged earth mites, etc.), snout mites, chiggers, hair follicle mites, velvet mites, water mites, etc.
Sarcoptiformes- oribatid, endeostigmatan, and astigmatan mites
Endeostigmata- basal sarcoptiform lineages
Oribatida- oribatid mites, beetle mites, armored mites (also cryptostigmata)
Astigmata- stored product, fur, feather, dust, and human itch mites, etc.
Parasitiformesare the group including ticks and a variety of mites.
Mesostigmata- bird mites, phytoseiid mites, raubmilben
Ixodida- hard and soft ticks
Opilioacariformesare a small order or suborder of parasitiform mites that are superficially similar to harvestmen( opiliones, hence their name). :Obsolete names::* Opilioacarida:* Notostigmata
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* (1993): Giftige und gefährliche Spinnentiere. "Westarp Wissenschaften" ISBN 3894324058
Experimental and Applied Acarology, ISSN: 1572-9702 (electronic) 0168-8162 (paper), Springer
*cite book |author=E. Baker |year=1952 |title=An Introduction to Acarology |publisher=New York: The MacMillan Company
*cite book |author=T. Woolley |year=1988 |title=Acarology: Mites and Human Welfare |publisher=New York:
Wiley Interscience|id=ISBN 0-47-104168-8
*cite book |author=R. B. Halliday, D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff |year=2001 |title=Acarology, Proceedings of the 10th International Congress [5-10 July 1998] |publisehr=
CSIRO Publishing, Melbourne |pages=960 pp |id=ISBN 0-643-06658-6
*cite book |author=D. E. Walter & H. C. Proctor |year=2001 |title=Mites in soil, an interactive key to mites and other soil microarthropods |publisher=ABRS Identification Series.
CSIRO Publishing, Collingwood, Victoria
*cite book |author=G. W. Krantz |year=1978 |title=A Manual of Acarology |edition=Second edition |publisher=
Oregon State UniversityBook Stores, Corvallis, OR |id=ISBN 0-882-46064-1
*cite web |url=http://tolweb.org/Acari/2554 |title=Acari. The Mites |work=
Tree of Life Web Project|author=David Evans Walter, Gerald Krantz & Evert Lindquist |date= 1996-12-13
**cite web |url=http://tolweb.org/Acariformes/2563 |author=Heather Proctor |date=
1998-08-09|title=Acariformes. The "mite-like" mites |work= Tree of Life Web Project
**cite web |url=http://tolweb.org/Parasitiformes |author=David Evans Walter |title=Parasitiformes. Holothyrans, ticks and mesostigmatic mites |date=
1996-12-13|work= Tree of Life Web Project
*cite web |url=http://www.lucidcentral.com/keys/lwrrdc/public/aquatics/aghydra/html/about.htm |title=Key to Families and Subfamilies of Water Mites (Hydracarina) in Australia |author=Mark Harvey & Heather Proctor
*cite web |url=http://www.lucidcentral.org/keys/v3/mites/Invasive_Mite_Identification/key/Whole_site/Home_whole_key.html |title=Invasive Mite Identification |author=David Evans Walter |date=
2006-09-15|publisher= Colorado State University, Ft. Collins, CO & USDA/APHIS/PPQ Center for Plant Health Science and Technology, Raleigh, NC
* [http://www.jove.com/index/details.stp?ID=737 Non-invasive 3D-visualization with sub-micron resolution using synchrotron-X-ray-tomography]
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