Temporal range: Early Devonian–recent
Peacock mite, Tuckerella sp.jpg
Peacock mite (Tuckerella sp.),
false-colour SEM, magnified 260×
Scientific classification e
Leach, 1817

and see text

The Acari (or Acarina) are a taxon of arachnids that contains mites and ticks. The diversity of the Acari is extraordinary and their fossil history goes back to at least the early Devonian period.[1] Acarologists (people who study the Acari) have proposed a complex set of taxonomic ranks to classify mites. In most modern treatments, the Acari are considered a subclass of the Arachnida and are composed of two or three superorders or orders: Acariformes (or Actinotrichida), Parasitiformes (or Anactinotrichida), and Opilioacariformes; the latter is often considered a subgroup within the Parasitiformes. The monophyly of the Acari is open to debate, and the relationships of the acarines to other arachnids is not at all clear.[2] In older treatments, the subgroups of the Acarina were placed at order rank, but as their own subdivisions have become better understood, treating them at the superorder rank is more usual.

Most acarines are minute to small (for example, 0.08–1.00 mm or 0.003–0.039 in), but the largest (some ticks and red velvet mites) may reach lengths of 10–20 mm (0.4–0.8 in). Over 50,000 species have been described (as of 1999) and an estimated million or more species may exist. The study of mites and ticks is called acarology (from Greek ἀκαρί/ἄκαρι, akari, a type of mite; and -λογία, -logia),[3] and the leading scientific journals for acarology include Acarologia, Experimental and Applied Acarology and the International Journal of Acarology.


Mites are arachnids, and as such, evolved from 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 fused, and a region of flexible cuticle (the circumcapitular furrow) separates the chelicerae and pedipalps from the rest of the body. This anterior body region is called the capitulum or gnathosoma, and according to some works, 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 (family Eriophyidae) have a worm-like 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'. Also, members of the Nematalycidae within the Endeostigmata, which live between sand grains, have often worm-like and elongated bodies with reduced legs.[4]

The mouth parts of mites may be adapted for biting, stinging, sawing, or sucking. They breathe 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 occur.[5]

Other Languages
العربية: قراديات
asturianu: Acari
azərbaycanca: Gənələr
башҡортса: Талпандар
беларуская: Кляшчы
български: Акари
brezhoneg: Akarian
català: Àcar
čeština: Roztoči
Cymraeg: Acari
dansk: Mider
Deutsch: Milben
eesti: Lestalised
Ελληνικά: Άκαρι
español: Acari
Esperanto: Akaro
euskara: Akaro
français: Acari
galego: Ácaros
한국어: 진드기아강
hrvatski: Acarina
Ido: Akaro
বিষ্ণুপ্রিয়া মণিপুরী: আকারি
Bahasa Indonesia: Tungau
Ирон: Гæбы
íslenska: Mítlar
italiano: Acarina
עברית: אקריות
Basa Jawa: Tungau
ქართული: ტკიპები
қазақша: Кенелер
Кыргызча: Кенелер
кырык мары: Пыйи
Latina: Acari
latviešu: Ērces
Lëtzebuergesch: Milben
Lingua Franca Nova: Acaro
magyar: Atkák
македонски: Крлежи
മലയാളം: അകാരിന
Nederlands: Acarina
日本語: ダニ
norsk: Midder
norsk nynorsk: Midd
occitan: Acari
oʻzbekcha/ўзбекча: Kanalar
Plattdüütsch: Mieten
português: Acarina
română: Acarieni
rumantsch: Chariels
Runa Simi: Khiki
Scots: Acari
Simple English: Acarina
slovenčina: Roztoče
slovenščina: Pršice
srpskohrvatski / српскохрватски: Acarina
suomi: Punkit
svenska: Kvalster
ትግርኛ: ሚተ
удмурт: Лемтэй
українська: Кліщі
اردو: علم حلم
vepsän kel’: Kägentäid
Tiếng Việt: Ve bét
粵語: 蜱蟎亞綱
中文: 蜱蟎亞綱