Acariformes
Encyclopedia
The Acariformes are the more diverse of the two superorders of mite
s. There are over 32,000 described species
in 351 families
, and an estimated total of 440,000 to 929,000, including undescribed species.
s - Sarcoptiformes
and Trombidiformes
. In addition, there is a paraphyletic group containing primitive forms, the Endeostigmata, which was formerly also considered distinct. The latter is composed of only 10 families of little-studied, minute, soft-bodied mites that ingest solid food, such as fungi, algae
and soft bodied invertebrate
s like nematode
s, rotifer
s and tardigrade
s. These clades were formerly considered suborders but this does not allow for a sufficiently precise classification of the mites and is abolished in more modern treatments; the Endeostigmata are variously considered to form a suborder on their own (the old view) or are included mainly in the Sarcoptiformes, thus making both groups monophyletic.
Another group often mentioned is the Actinedida. But in treatments like the present one this is split up between the Sarcoptiformes (and formerly the separate Endostigmata) and Trombidiformes (which contains the bulk of the "Actinedida"), because it appears to be a massively paraphyletic "wastebin taxon
", uniting all Acariformes that are not "typical" Oribatida
and Astigmata
. The Trombidiformes present their own problems. The small group Sphaerolichida appears to be the most ancient lineage among them. However, the Prostigmata
are variously subdivided into the Anystina and Eleutherengona, and Eupodina. The delimitation and interrelationships of these groups are entirely unclear; while most analyses find one of the latter two but not the other to be a subgroup of the Anystina, neither of these mutually contradicting hypotheses is very robust; possibly this is a simple error because phylogenetic software usually fails in handling non-dichotomous phylogenies. Consequently it may be best for the time being to consider each of the three main prostigmatan lineages to be equally distinct from the other two.
s and detritivore
s. Some Astigmata
– the Psoroptida – have become associated with vertebrate
s and nest-building insect
s. These include the well known house dust mite
s, scab mites and mange mites, stored product mites, feather mites and some fur mites. The relationships between their main groups are not well-resolved and subject to revision. In particular it appears as if the Oribatida
need to be split up in two, as the Astigmata
are closer to some of them (e.g. certain Desmonomata) than the latter are to other "Oribatida".
The Trombidiformes are most noted for the economic damage caused by many plant
parasite
species. All of the most important plant pests among the Acari are trombidiformans, such as spider mite
s (Tetranychidae) and Eriophyidae. Many species are also predators, fungivore
s and animal parasites. Some of the most conspicuous species of free-living mites are the relatively large and bright red velvet mites, that belong to the family Trombidiidae
.
Oribatid mites and to a much lesser extent others are a source of alkaloids in poison frogs (namely small species like the Strawberry Poison-dart Frog
Oophaga pumilio). Such frogs raised without these orbatids in their diet do not develop the strong poisons associated with them in the wild.
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Sarcoptiformes
Trombidiformes
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
s. There are over 32,000 described species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in 351 families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, and an estimated total of 440,000 to 929,000, including undescribed species.
Systematics and taxonomy
The Acariformes can be divided into two main cladeClade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s - Sarcoptiformes
Sarcoptiformes
Sarcoptiformes is an order of Acari....
and Trombidiformes
Trombidiformes
The Trombidiformes is a large, diverse order of mites, comprising around 125 families and more than 22,000 described species. The group has few synapomorphies by which it can be defined, unlike the other major group of acariform mites, Sarcoptiformes...
. In addition, there is a paraphyletic group containing primitive forms, the Endeostigmata, which was formerly also considered distinct. The latter is composed of only 10 families of little-studied, minute, soft-bodied mites that ingest solid food, such as fungi, algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and soft bodied invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s like nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s, rotifer
Rotifer
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703...
s and tardigrade
Tardigrade
Tardigrades form the phylum Tardigrada, part of the superphylum Ecdysozoa. They are microscopic, water-dwelling, segmented animals with eight legs. Tardigrades were first described by Johann August Ephraim Goeze in 1773...
s. These clades were formerly considered suborders but this does not allow for a sufficiently precise classification of the mites and is abolished in more modern treatments; the Endeostigmata are variously considered to form a suborder on their own (the old view) or are included mainly in the Sarcoptiformes, thus making both groups monophyletic.
Another group often mentioned is the Actinedida. But in treatments like the present one this is split up between the Sarcoptiformes (and formerly the separate Endostigmata) and Trombidiformes (which contains the bulk of the "Actinedida"), because it appears to be a massively paraphyletic "wastebin taxon
Wastebin taxon
Wastebasket taxon is a term used in some taxonomic circles to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by their lack of one or more distinct character states or by their not belonging to one or more other taxa...
", uniting all Acariformes that are not "typical" Oribatida
Oribatida
Oribatida , also known as moss mites or beetle mites, are an order of mites, in the "chewing Acariformes" clade Sarcoptiformes. They range in size from ....
and Astigmata
Astigmata
The Astigmatina are a "cohort" of mites. They belong to the Sarcoptiformes, which contain the "biting" Acariformes. Many species are parasites of vertebrates. Most notorious among these are the Psoroptidia, which contain such notable taxa as feather mites and Sarcoptes scabiei.The Astigmata are of...
. The Trombidiformes present their own problems. The small group Sphaerolichida appears to be the most ancient lineage among them. However, the Prostigmata
Prostigmata
The Prostigmata is a suborder of mites belonging to the Trombidiformes, which contain the "sucking" members of the "true mites" ....
are variously subdivided into the Anystina and Eleutherengona, and Eupodina. The delimitation and interrelationships of these groups are entirely unclear; while most analyses find one of the latter two but not the other to be a subgroup of the Anystina, neither of these mutually contradicting hypotheses is very robust; possibly this is a simple error because phylogenetic software usually fails in handling non-dichotomous phylogenies. Consequently it may be best for the time being to consider each of the three main prostigmatan lineages to be equally distinct from the other two.
Diversity
The Sarcoptiformes ingest solid food, being mainly microherbivores, fungivoreFungivore
A fungivore or mycophage is any animal that primarily or solely feeds upon living members of the fungus kingdom. Fungivory is a type of predation, and is an important part of the soil food web...
s and detritivore
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...
s. Some Astigmata
Astigmata
The Astigmatina are a "cohort" of mites. They belong to the Sarcoptiformes, which contain the "biting" Acariformes. Many species are parasites of vertebrates. Most notorious among these are the Psoroptidia, which contain such notable taxa as feather mites and Sarcoptes scabiei.The Astigmata are of...
– the Psoroptida – have become associated with vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s and nest-building insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s. These include the well known house dust mite
House dust mite
The house dust mite is a cosmopolitan guest in human habitation. Dust mites feed on organic detritus such as flakes of shed human skin and flourish in the stable environment of dwellings. House dust mites are a common cause of asthma and allergic symptoms worldwide...
s, scab mites and mange mites, stored product mites, feather mites and some fur mites. The relationships between their main groups are not well-resolved and subject to revision. In particular it appears as if the Oribatida
Oribatida
Oribatida , also known as moss mites or beetle mites, are an order of mites, in the "chewing Acariformes" clade Sarcoptiformes. They range in size from ....
need to be split up in two, as the Astigmata
Astigmata
The Astigmatina are a "cohort" of mites. They belong to the Sarcoptiformes, which contain the "biting" Acariformes. Many species are parasites of vertebrates. Most notorious among these are the Psoroptidia, which contain such notable taxa as feather mites and Sarcoptes scabiei.The Astigmata are of...
are closer to some of them (e.g. certain Desmonomata) than the latter are to other "Oribatida".
The Trombidiformes are most noted for the economic damage caused by many plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
parasite
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
species. All of the most important plant pests among the Acari are trombidiformans, such as spider mite
Spider mite
Spider mites are members of the Acari family Tetranychidae, which includes about 1,200 species. They generally live on the under sides of leaves of plants, where they may spin protective silk webs, and they can cause damage by puncturing the plant cells to feed...
s (Tetranychidae) and Eriophyidae. Many species are also predators, fungivore
Fungivore
A fungivore or mycophage is any animal that primarily or solely feeds upon living members of the fungus kingdom. Fungivory is a type of predation, and is an important part of the soil food web...
s and animal parasites. Some of the most conspicuous species of free-living mites are the relatively large and bright red velvet mites, that belong to the family Trombidiidae
Trombidiidae
Velvet mites are arachnids found in soil litter known for their bright red colours but are often mistaken for spiders. They are active predators as grown adults but early instars are often parasites on insects....
.
Oribatid mites and to a much lesser extent others are a source of alkaloids in poison frogs (namely small species like the Strawberry Poison-dart Frog
Strawberry Poison-dart Frog
The strawberry poison frog or strawberry poison-dart frog is a species of small amphibian poison dart frog found in Central America. It is common throughout its range, which extends from eastern central Nicaragua through Costa Rica and northwestern Panama...
Oophaga pumilio). Such frogs raised without these orbatids in their diet do not develop the strong poisons associated with them in the wild.
Examples
Sarcoptiformes
Sarcoptiformes is an order of Acari....
- Cheese miteCheese miteTyrophagus casei, the cheese mite, is a species of mite which is inoculated into and Altenburger Ziegenkäse cheese during their production...
s - EpidermoptidaeEpidermoptidaeEpidermoptidae is a family of acariform mites. They live as parasites on the skin of birds and mammals. They thrive in warm, damp areas of the skin ....
- GastronyssidaeGastronyssidaeGastronyssidae is a family of acariform mites which live as parasites on birds and mammals.-References:*...
- Sarcoptes scabieiSarcoptes scabieiSarcoptes scabiei or the itch mite is a parasitic arthropod that burrows into skin and causes scabies. Animals affected include not only human but also wild and domesticated dogs and cats in which it is one cause of mange...
Trombidiformes
Trombidiformes
The Trombidiformes is a large, diverse order of mites, comprising around 125 families and more than 22,000 described species. The group has few synapomorphies by which it can be defined, unlike the other major group of acariform mites, Sarcoptiformes...
- Demodex miteDemodex miteDemodex is a genus of tiny parasitic mites that live in or near hair follicles of mammals. About 65 species of Demodex are known; they are among the smallest of arthropods. Two species living on humans have been identified: Demodex folliculorum and Demodex brevis, both frequently referred to as...
- Eriophyidae, plant parasitesParasitismParasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
, e.g. Acalitus essigi (redberry mite) - ErythraeidaeErythraeidaeErythraeidae is a family of mites belonging to the Trombidiformes. Larval forms of these mites are parasitic on various other arthropods, for example harvestmen, but the adults are free-living predators. These oval mites are rather large, usually reddish coloured and densely hairy. The legs,...
- LabidostommatidaeLabidostommatidaeLabidostommatidae is a family of acariform mites. These egg-shaped free-living predators have the body completely covered with sclerotized plates, often with a reticulated pattern, two or three eyes and two claws on each tarsus.-References:*...
- Polydiscia deuterosminthurusPolydiscia deuterosminthurusPolydiscia deuterosminthurus is a species of mite recently discovered in the autonomous community of Navarre in Spain.Only the six-legged larval stage is so far known. This lives as a parasite on the springtail Deuterosminthurus bisetosus, which was discovered at the same time as the parasite...
- SmarididaeSmarididaeSmaridiidae is a family of mites belonging to the order Trombidiformes. These large predatory mites have long oval bodies, distinctively pointed in front. They are usually red and densely hairy with slender legs, sometimes very long...
- Spider miteSpider miteSpider mites are members of the Acari family Tetranychidae, which includes about 1,200 species. They generally live on the under sides of leaves of plants, where they may spin protective silk webs, and they can cause damage by puncturing the plant cells to feed...
s, e.g. Tetranychus urticaeTetranychus urticaeTetranychus urticae is one of many species of plant-feeding mites found in dry environments across the world, and generally considered a pest. It is the most widely known member of the family Tetranychidae or spider mites... - TarsonemidaeTarsonemidaeTarsonemidae is a family of mites, also called thread-footed mites or white mites.Only a limited number of tarsonemid genera are known to feed on higher plants while most species in this family feed on the thin-walled mycelia of fungi or possibly algal bodies...
, a number of which are plant pests, e.g. Acarapis woodiAcarapis woodiAcarapis woodi is a mite that is an internal parasite of honey bees, originally described from the Isle of Wight. Tracheal mites are related to spiders and have eight legs. Acarapis woodi live and reproduce in the tracheae of the bees... - TydeidaeTydeidaeTydeidae is a family of acariform mites. These are generally small mites with muted colours. The body is soft, often with complex striated or reticulated patterns...