MITES
(Acari)
Ian M. Smith, Evert E. Lindquist
and Valerie Behan-Pelletier
CASE STUDY - WATER MITES
(Ian M. Smith)CLASSIFICATION AND DIVERSITY
The basic classification, ecology and distribution of North American water mites were summarized at the subfamily level by Smith and Cook (1991).
Hydrovolzioidea. Members of Hydrovolzia mitchelli Habeeb (Fig. M-31), the only species of the holarctic family Hydrovolziidae known from the Mixedwood Plains, inhabit cold springs and seepage areas with water temperatures below 10o C. Deutonymphs and adults crawl slowly through moss mats and detritus, and larvae are parasites of adult Empididae (Diptera). This species has a Northeastern distribution, extending throughout the Mixedwood Plains and Atlantic Maritime Ecozones, and reaching its northern limit in southern regions of the Boreal Shield Ecozone (Smith 1991b). Other species of Hydrovolzia live in similar habitats in western North America and Eurasia.
Eylaoidea. The holarctic family Piersigiidae is represented in the Mixedwood Plains by members of Piersigia limnophila Protz. Adults of this species are large, slow moving mites inhabiting dense mats of detritus at the margins of ponds and temporary pools during early Spring. Larvae of P. limnophila are parasites of Water Scavenger beetles (Hydrophilidae) (Imamura and Mitchell 1967, Smith 1987). This rare species appears to have a Great Lakes Basin distribution, having been collected from widely scattered sites in the Mixedwood Plains and southern regions of the Boreal Shield Ecozones.
Four species representing 3 genera of the worldwide family Limnocharidae, a group of large, conspicuous red mites, occur in the Ecozone. Limnochares aquatica (Linnaeus) and L. americana Lundblad have widespread distributions in North America, and both are common in the Mixedwood Plains. Adults of L. aquatica are crawling mites in dense macrophyte beds in ponds and eutrophic lake edges or in Sphagnum mats in bog pools; larvae of this species parasitize Water Striders (Gerridae). Adults of L. americana are commonly seen swimming in ponds and lakes; their larvae are parasites of adult Odonata. Adults of Rhyncholimnochares kittitanniana Habeeb occur in riffles of shallow streams in Karst areas throughout the eastern United States and at scattered localities in the Mixedwood Plains and Atlantic-Maritime Ecozones (Fig.M-32). Larvae of this species parasitize Riffle Beetles (Elmidae) (B. Smith 1989). Species of Rhyncholimnochares occur in Australia and South America, and members of this apparently Gondwanan genus probably entered North America after the Panamanian Isthmus became established during Pliocene times. Adults of an undescribed species of the worldwide genus Neolimnochares have been collected in stream pools and ponds at several sites in the Mixedwood Plains and Atlantic-Maritime Ecozones.
About 25 species of Eylais, the only North American genus of the worldwide family Eylaidae, inhabit vernal temporary pools and ponds in the Mixedwood Plains. The conspicuous red adults of this genus are among the largest water mites, often reaching 5 mm. in length, and feed voraciously on ostracod crustaceans. Larvae of Eylais parasitize aquatic bugs (Hemiptera) and beetles (Coleoptera) (Lanciani 1969, 1970a-b; B. Smith 1986) and those of some species spend much of the year attached to hosts, completing development only after water refills their temporary pool habitats in spring (Wiggins et al. 1980). Recent systematic studies of Eylais have shown that the most reliable morphological characters for diagnosing species are found on the larval instar.
Hydrachnoidea. Adults of Hydrachna, the only genus in this worldwide group, are large (< 5 mm in diameter), rotund mites living in temporary pools and ponds. They apparently feed on eggs of aquatic insects. Members of the estimated 25 species inhabiting the Mixedwood Plains Ecozone are often abundant and readily observed in vernal temporary pools during May and June. Their larvae are parasites of aquatic bugs (Hemiptera) and beetles (Coleoptera) and may spend up to 9 months of the year on the host during the dry phase of the vernal temporary pool cycle (Wiggins et al. 1980). As in the case of Eylais, recent studies of the species in temperate North America confirm that larval features provide the most reliable characters for identifying the various species (B. Smith 1987). Some species, such as Hydrachna rotunda Marshall, parasitic on Water Scorpions (Nepidae) and Giant Water Bugs (Belostomatidae), have widespread distributions; others, including H. baculoscutata Crowell, a parasite of Backswimmers (Notonectidae), are known only from the Great Lakes Basin.
Hydryphantoidea. Over 20 species, representing 12 holarctic genera and 1 nearctic genus, of the family Hydryphantidae occur in the Mixedwood Plains. Adults of these species live in a wide variety of habitats and feed on eggs or early instar larvae of insects. Their larvae parasitize various adult insects, typically nematocerous flies (Diptera). Certain species of Euthyas, Panisopsis, Panisus, Tartarothyas, Thyas, Thyopsella and Protzia live in springs or riffles of cold streams (Smith 1991b) (Fig. M-33). Other species in the genera Hydryphantes, Euthyas, Thyas, Thyasides, Thyopsis and Zschokkea are restricted to temporary pools (Smith 1987, Wiggins et al. 1980). Most of the species in these two groups either have extensive Boreal distributions or have Northeastern distributions and congeneric sister species living in similar habitats in western North America. Members of Hydryphantes tenuabilis Marshall are unusual in that adults inhabit mesotrophic lakes and larvae parasitize Water Treader Bugs (Hydrometridae). This species has a Southeastern distribution, and apparently represents a species-group of Hydryphantes that evolved in South America and invaded North America across the Isthmus of Panama during the past 3 million years. Members of the rare species Trichothyas muscicola (Mitchell) are restricted to moss and algal mats in seepage areas and splash zones on rock faces in the eastern United States, and reach the northern limit of their distribution in the Niagara Gorge of the Lake Erie Lowland Ecoregion (Smith 1991b). Adults of Pseudohydryphantes latipalpus Marshall live in stream pools and oligotrophic lakes throughout the Boreal and Cordilleran Ecozones of North America, and this species reaches the southern limit of its distribution in the Mixedwoood Plains. Other species of this ancient genus occur in northern Eurasia and Australia. Adults of least one undescribed species of the worldwide genus Wandesia occur in hyporheic habitats in the Mixedwood Plains. Larvae of Wandesia parasitize stoneflies (Plecoptera).
Adults of Hydrodroma despiciens (Müller), the only species of the worldwide family Hydrodromidae known from the Mixedwood Plains, are common in permament lentic habitats throughout temperate North America (Smith 1987). Larvae of this species parasitize Chironomid Midges (Chironomidae) and Phantom Midges (Chaoboridae).
Members of Clathrosperchon americanus Habeeb occur in riffles of shallow streams and rivers throughout the eastern United States and reach the northern limit of their distribution in the Mixedwood Plains. The family Rhynchohydracaridae is of South American origin, and C. americanus and an undescribed species in western North America apparently dispersed into North America after formation of the Isthmus of Panama during the Pliocene.
Lebertioidea. Adults of most species of the holarctic genera Sperchon and Sperchonopsis (Sperchontidae), Bandakia (Anisitsiellidae), Lebertia (Lebertiidae) and Torrenticola and Testudacarus (Torrenticolidae) inhabit riffles in streams. Fast flowing streams are rare in the Mixedwood Plains compared to the Atlantic-Maritime and Cordilleran Ecozones, and these lebertioid genera consequently exhibit relatively low levels of species diversity (Conroy 1991a-b). In addition, these taxa have not been well studied in eastern North America, and many species remain undescribed or incompletely known. Spring-inhabiting species of these genera with Northeastern distributions, such as Sperchon decorellus Habeeb and Bandakia vietsi Cook, are common in the Mixedwood Plains (Smith 1979, 1991b). Several species representing southeastern clades that have invaded standing water (eg. Lebertia ontarioensis Marshall, L. quinquemaculosa Marshall and Torrenticola jordanensis Marshall) reach the northern limits of their distributions in the mesotrophic lakes of the Ecozone. In contrast, adults of the worldwide genera Oxus and Frontipoda (Oxidae) are adapted for living in lentic habitats, and most of the North American species of these genera inhabit the Mixedwood Plains. Some of these species, such as Frontipoda americana Marshall and Oxus connatus Marshall have Boreal distributions with their southern limits in the Mixedwood Plains. Other species of Oxus inhabiting the Ecozone appear to have either southeastern or Great Lakes Basin distributions. Larvae of most Lebertioidea parasitize Chironomid Midges (Chironomidae), but those of some species of Sperchontidae attack Blackflies (Simuliidae).
Hygrobatoidea. Species of 6 families of this large superfamily inhabit the Mixedwood Plains. Adult hygrobatoid mites live in a wide variety of habitats and feed on either early instar insect larvae or crustaceans. Larvae of nearly all taxa are parasites of Chironomid Midges (Chironomidae).
Nearly all of the species of Limnesiidae living in the Ecozone belong to holarctic species groups of the genus Limnesia. Adults of these species inhabit ponds and mesotrophic lakes (Smith 1987). Most of them have Southeastern distributions with their northern limits in the southern regions of the Boreal Shield Ecozone, although a few that appear to live only in bog pools have Northeastern distributions. All other North American taxa of Limnesiidae apparently originated in South America and have their greatest species diversity in the southern United States. Members of 2 southern genera occur in southeastern Canada, but species of only one of them, Tyrrellia, inhabit the Mixedwoood Plains. Adults of T. circularis Koenike and T. ovalis Marshall have the unusual habit of living in the surface film on wet detritus and emergent vegetation at the edges of springs, streams, ponds and lakes. Larvae of this genus are also exceptional in parasitizing Biting Midges (Ceratopogonidae).
The large worldwide family Hygrobatidae is represented in the Mixedwood Plains by several species of the holarctic genera Atractides and Hygrobates living in springs, streams and lakes (Smith 1987, 1991b). Most of the species of Atractides inhabit stream riffles and appear to have Southeastern distributions, but one, Atractides nodipalpis (Thor), is widespread in Boreal Ecozones. Adults of at least 4 species of Hygrobates inhabit springs in the Mixedwoood Plains and have either Northeastern or Boreal distributions (Smith 1991b). Other species [eg. H. longipalpis (Hermann)] living in ponds and lakes are distributed widely in the eastern United States and southeastern Canada (Smith 1987).
The tiny and strongly flattened adults of several species of Feltria, the only genus in the holarctic family Feltriidae, live in cold springs and both hyporheic and riffle habitats in streams in the Mixedwood Plains. Most of the species inhabiting surficial substrata (eg. Feltria purpurotincta Habeeb) have Northeastern distributions, but those restricted to subsurface gravels (eg. Feltria cornuta Walter) are essentially Southeastern and do not occur north of the Great Lakes Basin.
Numerous species representing 3 genera of the family Unionicolidae inhabit stream pools, ponds and lakes in the Mixedwood Plains (Cook 1976a, Smith 1987, Conroy 1991c-d, 1992 a-b). Most of the 15 species of the worldwide genus Neumania represent holarctic species groups and have either Southeastern or Great Lakes Basin distributions. However, one species, N. distincta Marshall, belongs to a clade that is well represented in tropical North America and South America. The 3 species of the worldwide genus Unionicola with free living predaceous adults have Boreal distributions. The others, whose adults are parasitic in the mantle cavity of molluscs, have Southeastern distributions with northern limits in the Great Lakes Basin. All 6 species of the genus Koenikea recorded from the Ecozone have Southeastern distributions with northern limits in the Mixedwood Plains or southern regions of the Boreal Shield Ecozone. This genus apparently originated in Gondwanaland, and species groups occuring in North America represent invasions during late Tertiary times.
Over 50 species representing 11 genera of the family Pionidae have been reported from the Mixedwood Plains (Smith 1976a, Simmons and Smith 1984). Adults of Wettina ontario Smith live in stream pools and oligotrophic lakes in scattered localities in the eastern United States and throughout the Mixedwood Plains, Atlantic-Maritime and Boreal Ecozones of Canada. Those of W. octopora Cook are known only from springs and stream pools in a few localities in the Mixedwood Plains. Other species of Wettina inhabit Cordilleran regions of western North America and northern Eurasia, and related genera of this ancient clade live in Australia. At least 3 species of the holarctic genus Hydrochoreutes live in stream pools and lakes in the Mixedwood Plains (Smith 1976a, 1987). Two of these, H. michiganensis Cook and H. schizopetiolatus Cook, have Southeastern distributions. The other, H. microporus Cook, is distributed throughout the Boreal Ecozones of Canada and may reach its southern limit in the Mixedwood Plains.
Two species of the holarctic genus Pseudofeltria inhabit springs in the Mixedwood Plains. Pseudofeltria multipora Cook has a Northeastern distribution and a undescribed species has been collected at a few sites in the St. Lawrence Lowlands. Eight species of the related holarctic genus Forelia live in stream pools, ponds and lakes in the Ecozone (Smith 1976a, 1987), and most of them have Southeastern or Great Lakes Basin distributions.
Members of Huitfeldtia rectipes Thor, a holarctic mite that occurs throughout Boreal and Arctic Ecozones, inhabit the profundal zone of oligotrophic lakes in the Mixedwood Plains at the southern limit of the distribution for the species (Smith 1976a). One species of the nearctic genus Neotiphys, N. pionoidellus (Habeeb), has a Southeastern distribution and is common in stream pools in the Ecozone (Smith 1976a). Adults of Pionopsis paludis Habeeb inhabit temporary pools in the Mixedwood Plains at the western edge of the Northeastern distribution of the species (Smith 1987). An undescribed species of this holarctic genus appears to have a Boreal distribution and has been collected in stream pools in northern parts of the Mixedwood Plains. Ten species of the holarctic genus Tiphys occur in the Ecozone (Smith 1976a, 1987). One of them, T. diversus (Marshall), inhabits stream pools and lakes and has a Southeastern distribution. An undescribed species has been collected in cold water pools associated with springs in the St. Lawrence Lowlands. The other 8 species live in vernal temporary pools and have either Northeastern or Boreal distributions. These mites survive the dry phase of the temporary pool cycle as deutonymphs by embedding their mouthparts at the leaf axils of mosses and becoming quiescent until water returns to the pool basin during the following Spring (Wiggins et al. 1980).
Najadicola ingens Koenike, a Southeastern species, is locally common in lakes in the Mixedwood Plains and southern regions of the Boreal Shield Ecozones. Deutonymphs and adults live as commensals in the mantle cavity of mussels and larvae parasitize chironomid midges (Simmons and Smith 1984). Similar species of this unusual genus live in southeastern Asia.
The holarctic genus Nautarchna is represented in the Mixedwood Plains by two species with Boreal distributions (Smith 1972, 1976a). Members of N. muskoka Smith live in stream pools and those of N. queticoensis inhabit springs. Over 20 species of the holarctic genus Piona occur in standing water habitats in the Mixedwood Plains (Smith 1976a). Six of these species [eg. P. conglobata (Koch) and P. neumani (Koenike)] live primarily in permanent ponds and have widespread distributions; about 15 other species [eg. P. pugilis (Wolcott) and P. spinulosa (Wolcott)] inhabit mesotrophic lakes and have Great Lakes Basin distributions. The other 5 species are restricted to vernal temporary pools and have either Northeastern or Boreal distributions. They are adapted to survive drought in the same way as temporary pool inhabiting species of Tiphys.
At least 25 species of the worldwide family Aturidae are known from the Mixedwood Plains. Several holarctic genera are represented in the Ecozone by one or two common species with either Northeastern or Boreal distributions (Smith 1977b). Adults of Ljania bipapillata Thor and L. michiganensis Cook occur in stream riffles, while those of Brachypoda cornipes Habeeb, B. setosicauda Habeeb and Woolastookia pilositarsa (Habeeb) live in stream pools. Members of Axonopsis setoniensis Habeeb and an undescribed species of Woolastookia inhabit both stream pools and lakes. Two species of the worldwide genus Albia occur in the Mixedwood Plains; the Southeastern species A. caerulea Marshall is commonly found in lakes and the Northeastern species A. neogaea Habeeb is rarely collected in stream pools. Several species in the holarctic genera Aturus and Kongsbergia are among the dominant mites in stream riffles in the Ecozone (Fig.M-34), but these taxa have not yet been well studied and species identities remain uncertain. As in the case of predominantly rheobiontic taxa of Lebertioidea, aturid genera such as Aturus and Axonopsis exhibit lower species diversity in the Mixedwood Plains than they do in the Atlantic-Maritime Ecozone.
Arrenuroidea. One hundred and twenty-one species representing 15 genera and 10 families of this superfamily have been recorded from the Mixedwood Plains. Nineteen of these species have not yet been described. Eighty-seven species belong to the genus Arrenurus, making the Mixedwood Plains the region of highest species diversity in North America for this remarkable worldwide clade.
Momoniidae. Two species of this ancient worldwide family belonging to different holarctic genera occur commonly in the Ecozone (Smith 1989, 1991a). Adults of Momonia campylotibia Smith inhabit stream pools and those of Stygomomonia riparia Habeeb live in hyporheic gravels. Both of these species have Southeastern distributions, and have closely related congeners living in similar habitats in the eastern United States and western North America (Fig.M-35, Fig.M-36).
Nudomideopsidae. Members of Nudomideopsis magnacetabula (Smith), the only species of this ancient family known from eastern North America, inhabit springs and hyporheic gravels in the Mixedwood Plains (Smith 1977a, 1983a, 1990b). This rare species has a Northeastern distribution (Fig.M-37), and its closest known relatives live in Eurasia. Other species of the family live in springs and subterranean waters in western North America.
Mideidae. Adults of Midea expansa Marshall, a rare species in the Ecozone, may be locally abundant in ponds and mesotrophic lakes in eastern Ontario (Smith 1978). This mite has a Great Lakes Basin distribution, and its nearest known relative lives in lakes in Europe. Another species of this genus, Midea alaris Young, inhabits bog pools in the Boreal Shield Ecozone but has not yet been reported from the Mixedwood Plains.
Mideopsidae. Sixteen species representing two subgenera of the holarctic genus Mideopsis are known from the Ecozone (Cook 1976b). Adults of the 7 species of the subgenus Mideopsis are strong swimmers. Mideopsis crassipes Soar is a common mite in stream pools throughout the Mixedwood Plains, Atlantic-Maritime and Boreal Ecozones in Canada. Members of the same species, or a very closely related one, live in both pools and riffles of streams in the southeastern United States, and those of several other species in the same group inhabit streams in western North America. The other 6 species of this subgenus present in the Ecozone segregate evenly into the closely related borealis and americana groups, both of which are represented in virtually all standing water habitats in the Ecozone. Mideopsis borealis Habeeb has a widespread distribution. Although apparently restricted to small stream habitats in the eastern United States and southeastern Canadian Ecozones, members of this species are able to exploit both stream pools and lakes in the Boreal Ecozones of Canada. A number of closely related species live in stream pools in the southwestern United States and Mexico. Two relatively rare species of the borealis group inhabit stream pools in the Mixedwood Plains. Mideopsis fibrosa Lundblad has a Southeastern distribution and occurs in both streams and lakes as far north as the edge of the Boreal Shield Ecozone. Mideopsis gladiator Habeeb is known from streams in scattered localities in the eastern United States and reaches the northern limit of its distribution in the Manitoulin-Lake Simcoe Ecoregion. Populations of a very similar species occur in riverine pools in northeastern California. Mideopsis americana Marshall occurs throughout temperate North America from the Atlantic to the Pacific Coast. The two other species of the americana group known from the Mixedwood Plains have more restricted distributions. The Southeastern species Mideopsis lamellipalpis Lundblad is common in the Ecozone and reaches its northern limit in the southern regions of the Boreal Shield Ecozone. On the other hand, the relatively rare Boreal species Mideopsis marshallae Cook occurs at scattered localities in the Mixedwood Plains representing the southern limit of its distribution.
Adults of the 9 species belonging to the subgenus Xystonotus are crawling mites. Members of M. wolcotti Cook, a rare species with Northeastern distribution, occur in moss mats in springs and seepage areas in both the Mixedwood Plains and Atlantic-Maritime Ecozones. Adults of a related undescribed species have been found in similar habitats along the Niagara Escarpment in the Lake Erie Lowland. Adults of M. robusta (Habeeb) have a Boreal distribution and are common in thick detritus in stream pools, bog pools and ponds in the Mixedwood Plains. Members of M. aspera (Wolcott) live in dense macrophyte beds in mesotrophic lakes in the Great Lakes Basin, and those of a closely related undescribed species occur in stream pools in the Mixedwood Plains and scattered localities in the eastern United States. Three species of Xystonotus with Southeastern distributions occur in streams in the Mixedwood Plains. Members of M. delicata (Habeeb) and a rare, closely related, undescribed species live in surface riffles and those of M. interstitialis Cook inhabit hyporheic gravels. Adults of a rare undescribed species that is closely related to Mideopsis pumila Cook from western North America have been collected in hyporheic gravels of streams in the Mixedwood Plains and Atlantic-Maritime Ecozones.
Chappuisididae. Uchidastygacarus acadiensis Smith has a Northeastern distribution. Members of this uncommon species inhabit hyporheic gravels throughout the Atlantic-Maritime Ecozone and at scattered localities in the Mixedwood Plains and southern regions of the Boreal Shield Ecozone (Smith 1983b, 1992b) (Fig.M-38). Members of 2 closely related species occur in hyporheic habitats in the eastern United States and other members of the genus occur in the western United States and eastern Asia (Smith 1992b).
Athienemanniidae. Members of Chelomideopsis besselingi (Cook) (Fig.M-39, Fig.M-40), another mite with a Northeastern distribution, are commonly found crawling on moss mats and detritus in springs in the Mixedwood Plains (Smith 1991b, 1992a). Adults of a rare, closely related species occur in springs in the Atlantic-Maritime Ecozone and other species of the genus live in similar habitats in western North America and Eurasia. The type locality of Stygameracarus canadensis Smith is a stream in the Lake Erie Lowlands and the only other known locality for this rare mite is a stream in Georgia. The only other species of this genus occurs in a similar habitat in Oklahoma (Smith 1990a).
Acalyptonotidae. This family is represented in the Mixedwood Plains by the only species of the genus Paenecalyptonotus, P. fontinalis Smith, a rare mite with a Northeastern distribution (Fig.M-41). Adults inhabit springs at a few localities in the St. Lawrence Lowlands and Manitoulin-Lake Simcoe Ecoregions, Atlantic-Maritime Ecozone and southern edge of the Boreal Shield Ecozone (Smith 1976c). Species of the other genus in the family, Acalyptonotus, live in springs and ponds in alpine areas of western North America and Arctic regions of both North America and Eurasia.
Neoacaridae. Six species in 2 genera of this holarctic family occur in the Mixedwood Plains. Two species of the genus Neoacarus with different distribution patterns inhabit hyporheic gravels in streams of the Ecozone. Members of Neoacarus similis Cook, a mite with Southeastern distribution, occur at various localities in the Ecozone, and those of Neoacarus motasi Cook, a Northeastern mite, live in a stream in the Lake Erie Lowlands. Adults of the unusual species Neoacarus lacus Smith have been found only on macrophytes in mesotrophic lakes in eastern Ontario (Smith 1976b). Members of 2 undescribed species of Neoacarus have been collected from spring habitats in the St. Lawrence and Lake Erie Lowland Ecoregions. Several other species of this genus occur in hyporheic habitats in eastern and western North America, and one species lives in surficial riffles of streams in Europe. Adults of an undescribed species of the nearctic genus Volsellacarus inhabit hyporheic gravels in a stream in the Lake Erie Lowlands. Other species of this genus live in similar habitats in both eastern and western North America.
Laversiidae. The only species of this nearctic genus, Laversia berulophila Cook, occurs in cold springs with water temperature below 10 C throughout Boreal and Corilleran areas of North America (Smith 1991b) (Fig.M-42). Members of this species are common in springs in the Mixedwood Plains and have also been collected from profundal substrata in Georgian Bay.
Krendowskiidae. Species of 4 species representing 2 genera of this family occur in the Ecozone. Members of Geayia ovata (Wolcott) occur in ponds and lakes throughout the eastern United States and reach the northern limit of their distribution in the Mixedwood Plains. Geayia ontario Smith was originally described from specimens collected in stream pools in the Manitoulin-Lake Simcoe Ecoregion (Smith 1983c) and is now known to occur in similar habitats at several localities in the eastern United States. Adults of a third species of Geayia, thus far undescribed, have been collected from stream pools in eastern Ontario. Many other species of Geayia are known from the southern United States, Mexico and South America, and members of the genus probably invaded North America by crossing the Ishtmus of Panama during the Pliocene. Krendowskia similis Viets occurs in stream pools and lakes in the Great Lakes Basin, including several at localities in the St. Lawrence Lowland Ecoregion (Smith 1978). Many other species of this genus live in the southern United States, Mexico and especially South America, and one species inhabits lakes in Europe. Members of this genus probably also dispersed into North America across the Panamanian Isthmus during late Tertiary times.
Arrenuridae. Eighty-seven species of the large, worldwide genus Arrenurus inhabit the Mixedwood Plains (Fig.M-43). Ten species of the subgenus Truncaturus, including 2 which are undescribed, occur in the Ecozone. Adults typically inhabit moss mats and detritus in vernal temporary pools and the semipermanent margins of springs, bog pools and ponds, and known larvae parasitize mosquitoes. Most of these species are known only from the Great Lakes Basin but both A. lacrimatus Cook and A. kenki Marshall have also been found at localities scattered throughout the Boreal Ecozones of Canada. Known larvae are parasites of mosquitoes (Culicidae) (Mullen).
Adults of 12 species of Micruracarus have been collected from stream pools, ponds and mesotrophic lakes in the Mixedwood Plains. Known larvae parasitize chironomid midges of the subfamily Tanypodinae. Six of these species are known only from the Great Lakes Basin. Three species have Southeastern distributions, with that of A. acutus Marshall reaching its northern limit in the Ecozone and those of A. setiger Koenike and A. bicaudatus Marshall extending into the southern edge of the Boreal Shield Ecozone. The other 3 species have Boreal distributions with their southern limits in the Mixedwood Plains; A. crenellatus Marshall occurs from Nova Scotia to British Columbia, A. ovalis Marshall is recorded from Newfoundland to Alberta and A. pseudosetiger Marshall has been collected from Ontario to Alberta.
Members of 35 species of Megaluracarus, of which 2 are undescribed, have been recorded from the Ecozone. Adults of most species inhabit stream pools, ponds and lakes, but those of A. mamillanus Marshall live in springs and those of an undescribed species inhabit hyporheic gravels in small streams. Members of 4 other species are able to exploit vernal temporary pools. Known larvae are parasites of tanypodine chironomid midges. Sixteen species of Megaluracarus have Southeastern distributions. One species group, including A. marshallae Piersig, A. intermedius Marshall, A. megalurus Marshall and A. pseudotenuicollis Wilson, belongs to a clade of South American origin that is well represented in Florida and Mexico and probably entered North America during late Tertiary times. Arrenurus opisthifoliacercus Young lives in stream pools from the Hill Country of Texas to southern Ontario. Two other species, A. pseudaphelocercus Wilson and A. unisinuatus Wilson, inhabit thick macrophyte beds in pools associated with springs and cold streams along the western edge of the Appalachians from Tennessee to the Mixedwood Plains. Members of A. pseudocylindratus Piersig and A. cardiacus Marshall are among the most common and numerous mites in lakes throughout the eastern United States and the southeastern Ecozones of Canada. Eleven species of this subgenus have Northeastern distributions, including the crenobiontic A. mamillanus mentioned above. Several of them (eg. A. elevatus Marshall, A. longicaudatus Marshall, A. pseudoconicus Piersig, A. semicircularis Marshall and A. solifer Marshall) typically live in oligotrophic lakes and reach the southwestern limit of their distributions in the eastern Mixedwood Plains. Three Northeastern species inhabit vernal temporary pools, including A. neobirgei Cook, A. neomamillanus Cook and 3 undescribed species. One of the 2 species of Megaluracarus with Great Lakes Basin distributions, A. rotundus Marshall, is common in small ponds; the other, A. dinotoformis Cook, is known only from moss mats at the intermittent margins of boggy pools in a few locations. One of the species with Boreal distribution, A. siegasianus Habeeb, is found commonly in sluggish streams from Newfoundland to Alberta. Another, A. rawsoni Marshall, inhabits profundal substrata in deep oligotrophic lakes. Arrenurus wardi Marshall is one of the most common and abundant species of water mite in nutrient-rich standing water habitats throughout temperate North America.
Thirty-three species of the subgenus Arrenurus are known to occur in the Mixedwood Plains, including 6 undescribed species. Adults of most of them inhabit stream pools, ponds and mesotrophic lakes, but those of A. serratus Marshall have only been found at profundal depths in oligotrophic lakes. A few species, such as A. dentipetiolatus Marshall, A. drepanophorus Cook and A. pollictus Marshall, live only in small permanent ponds and one species, A. planus Marshall, lives exclusively in vernal temporary pools. The hosts of all known larvae of this subgenus are Odonata. Ten species of the subgenus Arrenurus, about 1/3 of the total number in the Ecozone, have Southeastern distributions. Some of them, such as A. falcicornis Marshall, A. flabellifer Marshall, A. magnicaudatus Marshall, A. major Marshall, A. pseudosuperior Cook and A. superior Marshall are among the most common water mites in the mesotrophic lakes of eastern North America from the Gulf of Mexico to the Mixedwood Plains. Members of another species, A. pinguisomus Cook, have been collected only in dense macrophyte beds in ponds and shallow lakes at scattered localities from Texas to eastern Ontario. Larvae of this species apparently parasitize dragonflies that are restricted to eutrophic habitats and may be in the process of extending their ranges into the eastern Mixedwood Plains. The rare Southeastern species Arrenurus pleopetiolatus Marshall and A. laticornis Marshall have each been collected only once in the Ecozone, at localities in eastern Ontario. Eleven of the species in this subgenus, another 1/3 of the total number, are known only from the Great Lakes Basin. Most of them are uncommon species (eg. A. compactilis Marshall, A. dentipetiolatus Marshall, A. drepanophorus Cook, and 6 undescribed species) typically found in dense macrophyte growths in permanent ponds and shallow lakes. Larvae of Arrenurus planus Marshall parasitize damselflies that breed in temporary pools. After engorging on their host, these larvae enter a diapause within a thick, impervious cuticle and drop to the dry pond bed where they remain until water returns during the following Spring. Closely related species with similar life histories live in temporary pools in western North America and Europe. Four of the species with Boreal distributions, namely A. mucronatus Lavers, A. paracascadensis Conroy, A. pollictus Marshall and A. reflexus Marshall, occur commonly in ponds and sloughs from Ontario westward to at least Saskatchewan. The other Boreal species, Arrenurus serratus Marshall, has been found in deep lakes from Quebec to Saskatchewan. The widespread species Arrenurus americanus Marshall is one of the most common water mites in lakes and ponds from coast to coast in temperate North America. All of the species in this subgenus with Northeastern distributions have close relatives living further south. Arrenurus fissicorniformis Cook replaces A. fissicornis Marshall in eastern parts of the Mixedwood Plains and the Atlantic-Maritime Ecozone; similarly A. tetratumuli Munchberg replaces A. pseudosuperior Cook in the northern part of the Mixedwood Plains and the Boreal Shield Ecozone. Lastly, the western species Arrenurus hungerfordi Cook is common in ponds and sloughs throughout the Prairies and northern Plains, and reaches the eastern limit of its distribution in the Mixedwood Plains Ecozone.
TABLE 5: SELECTED BIOLOGICAL DATA FOR SPECIES OF ARRENUROIDEA
IN MIXEDWOOD PLAINS ECOZONE
Habitat Codes: Springs (Sp); Groundwater/Hyporheos (Hyp); Stream
Riffles (StRif); Stream Pools (StPl); Bog Pools (BPl); Ponds/Marshes
(Pd); Vernal Temporary Pools (TPl); Oligotrophic Lakes (OL) and
Mesotrophic Lakes (ML)
| TAXON | REFERENCE | DISTRIBUTION | 132/ 133 | 134 | 135 | HABITAT | HOST GROUP |
| Momoniidae | |||||||
| Momonia campylotibia | Smith 1989, CNC | Southeastern | X | X | StPl, Pd | Trichoptera | |
| Stygomomonia riparia Habeeb | Smith 1991a, CNC | Southeastern | X | X | X | Hyp | Trichoptera |
| Nudomideopsidae | |||||||
| Nudomideopsis magnacetabula (Smith) | Smith 1990b, CNC | Northeastern | X | X | Sp, Hyp | Chironomidae | |
| Mideidae | |||||||
| Midea expansa Marshall | Smith 1978, CNC | Great Lakes Basin | X | X | Pd, ML | Chironomidae | |
| Mideopsidae | |||||||
| Mideopsis (s.s.) americana Marshall | Smith 1978, CNC | Widespread | X | X | X | StPl, Pd, ML, OL | Chironomidae |
| Mideopsis (s.s.) borealis Habeeb | Smith 1978, CNC | Widespread | X | X | X | StPl, Pd, OL | Chironomidae |
| Mideopsis (s.s.) crassipes Soar | Smith 1978, CNC | Northeastern | X | X | StPl | Chironomidae | |
| Mideopsis (s.s.) fibrosa Lundblad | Smith 1978, CNC | Northeastern | X | X | StPl, Pd, OL | Chironomidae | |
| Mideopsis (s.s.) gladiator Habeeb | CNC | Widespread | X | StPl | Unknown | ||
| Mideopsis (s.s.) lamellipalpis Lundblad | CNC | Southeastern | X | X | X | StPl, ML | Unknown |
| Mideopsis (s.s.) marshallae Cook | Smith 1978, CNC | Boreal | X | X | StPl, Pd, ML | Unknown | |
| Mideopsis (X.) aspera (Wolcott) | Smith 1978, CNC | Great Lakes Basin | X | X | X | StPl, ML, OL | Chironomidae |
| Mideopsis (X.) delicata (Habeeb) | CNC | Southeastern | X | X | StRif | Chironomidae | |
| Mideopsis (X.) interstitialis Cook | CNC | Southeastern | X | X | Hyp | Unknown | |
| Mideopsis (X.) robusta (Habeeb) | Smith 1987, CNC | Boreal | X | X | StPl, BPl, Pd, TPl, ML | Chironomidae | |
| Mideopsis (X.) wolcotti Cook | Smith 1991b, CNC | Great Lakes Basin | X | X | Sp | Chironomidae | |
| Mideopsis (X.) n. sp. # 1 | CNC | Great Lakes Basin | X | X | StPl | Unknown | |
| Mideopsis (X.) n. sp. # 2 | CNC | Southeastern | X | StRif | Unknown | ||
| Mideopsis (X.) n. sp. # 3 | CNC | Southeastern | X | Sp | Chironomidae | ||
| Mideopsis (X.) n. sp. # 4 | CNC | Northeastern | X | X | X | Hyp | Unknown |
| Chappuisididae | |||||||
| Uchidastygacarus acadiensis Smith | Smith 1992b, CNC | Northeastern | X | Hyp | Unknown | ||
| Athienemanniidae | |||||||
| Chelomideopsis besselingi (Cook) | Smith 1992a, CNC | Eastern | X | X | Sp | Chironomidae | |
| Stygameracarus canadensis Smith | Smith 1990a, CNC | Southeastern | X | Hyp | Unknown | ||
| Acalyptonotidae | |||||||
| Paenecalyptonotus fontinalis Smith | Smith 1976c, CNC | Northeastern | X | X | Sp | Unknown | |
| Neoacaridae | |||||||
| Neoacarus lacus Smith | Smith 1976b, CNC | Great Lakes Basin | X | X | ML | Unknown | |
| Neoacarus motasi Cook | CNC | Southeastern | X | StRif, Hyp | Unknown | ||
| Neoacarus similis Cook | CNC | Southeastern | X | X | StRif, Hyp | Unknown | |
| Neoacarus n. sp. # 1 | CNC | Southeastern | X | X | X | Hyp | Unknown |
| Neoacarus n. sp. # 2 | CNC | Great Lakes Basin | X | X | X | Sp | Unknown |
| Volsellacarus n. sp. | CNC | Southeastern | X | Hyp | Chironomidae | ||
| Laversiidae | |||||||
| Laversia berulophila Cook | Smith 1991b, CNC | Boreal | X | X | Sp, OL | Chironomidae | |
| Krendowskiidae | |||||||
| Geayia ontario Smith | Smith 1983c, CNC | Great Lakes Basin | X | StPl | Unknown | ||
| Geayia ovata (Wolcott) | Smith 1978, CNC | Southeastern | X | X | StPl, Pd, ML | Chironomidae | |
| Geayia n. sp. | CNC | Great Lakes Basin | X | StPl | Unknown | ||
| Krendowskia similis Viets | Smith 1978, CNC | Southeastern | X | X | StPl, Pd, ML, OL | Chironomidae | |
| Arrenuridae | |||||||
| Arrenurus (Trunc.) acuminatus Mullen | Smith 1987, CNC | Great Lakes Basin | X | TPl | Culicidae | ||
| Arrenurus (Trunc.) angustilimbatus Mullen | Smith 1987, CNC | Great Lakes Basin | X | TPl | Culicidae | ||
| Arrenurus (Trunc.) danbyensis Mullen | Smith 1987, CNC | Great Lakes Basin | X | X | BPl, Pd, TPl | Culicidae | |
| Arrenurus (Trunc.) kenki Marshall | Smith 1987, CNC | Boreal | X | X | X | Pd, TPl | Culicidae |
| Arrenurus (Trunc.) lacrimatus Cook | CNC | Boreal | X | X | X | Pd, TPl | Culicidae |
| Arrenurus (Trunc.) palustris Mullen | Smith 1987, CNC | Boreal | X | X | X | Pd, TPl | Culicidae |
| Arrenurus (Trunc.) ringwoodi Mullen | CNC | Great Lakes Basin | X | X | BPl, Pd, TPl | Culicidae | |
| Arrenurus (Trunc.) rufopyriformis Habeeb | CNC | Northeastern | X | X | BPl, TPl | Culicidae | |
| Arrenurus (Micr.) acutus Marshall | CNC | Southeastern | X | StPl, Pd, ML | Unknown | ||
| Arrenurus (Micr.) bicaudatus Marshall | CNC | Southeastern | X | X | StPl, Pd, ML | Unknown | |
| Arrenurus (Micr.) cheboyganensis Cook | CNC | Great Lakes Basin | X | X | StPl, Pd, ML, OL | Unknown | |
| Arrenurus (Micr.) crenellatus Marshall | CNC | Boreal | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Micr.) hiatocaudatus Cook | CNC | Great Lakes Basin | X | X | X | StPl, ML | Unknown |
| Arrenurus (Micr.) infundibularis Marshall | CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Micr.) laticaudatus Marshall | CNC | Great Lakes Basin | X | X | X | Pd, ML | Unknown |
| Arrenurus (Micr.) lyriger Marshall | CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Micr.) ovalis Marshall | CNC | Boreal | X | X | BPl, Pd | Unknown | |
| Arrenurus (Micr.) pseudosetiger Marshall | CNC | Boreal | X | X | StPl, BPl, Pd, TPl | Unknown | |
| Arrenurus (Micr.) scutulatus Marshall | CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Micr.) setiger Koenike | CNC | Southeastern | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Meg.) alticorpus Wilson | CNC | Southeastern | X | X | StPl, ML, OL | Unknown | |
| Arrenurus (Meg.) apetiolatus Piersig | CNC | Southeastern | X | X | X | StPl, Pd, ML, OL | Unknown |
| Arrenurus (Meg.) bartonensis Cook | Smith 1987, CNC | Southeastern | X | StPl, Pd, ML | Unknown | ||
| Arrenurus (Meg.) birgei Marshall | Smith 1987, CNC | Southeastern | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Meg.) cardiacus Marshall | CNC | Southeastern | X | X | StPl, Pd, ML, OL | Unknown | |
| Arrenurus (Meg.) dinotoformis Cook | CNC | Great Lakes Basin | X | BPl, Pd | Unknown | ||
| Arrenurus (Meg.) elevatus Marshall | CNC | Northeastern | X | StPl, Pd, ML, OL | Unknown | ||
| Arrenurus (Meg.) intermedius Marshall | CNC | Southeastern | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Meg.) longicaudatus Marshall | CNC | Northeastern | X | StPl, Pd, ML, OL | Unknown | ||
| Arrenurus (Meg.) mamillanus Marshall | Smith 1991b, CNC | Northeastern | X | X | Sp | Chironomidae | |
| Arrenurus (Meg.) manubriator Marshall | CNC | Southeastern | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Meg.) marshallae Piersig | CNC | Southeastern | X | X | X | StPl, Pd, ML | Unknown |
| Arrenurus (Meg.) megalurus Marshall | Smith 1987, CNC | Southeastern | X | X | StPl, Pd, ML | Unknown | |
| Arrenurus (Meg.) neobirgei Cook | Smith 1987, CNC | Northeastern | X | X | X | Pd, TPl | Unknown |
| Arrenurus (Meg.) neomamillanus Cook | CNC | Northeastern | X | X | X | Pd, TPl | Chironomidae |
| Arrenurus (Meg.) opisthifoliacercus Young | CNC | Southeastern | X | X | X | StPl | Unknown |
| Arrenurus (Meg.) pseudaphelocercus Wilson | CNC | Southeastern | X | X | StPl, Pd | Unknown | |
| Arrenurus (Meg.) pseudocaudatus Marshall | CNC | Boreal | X | StPl | Unknown | ||
| Arrenurus (Meg.) pseudoconicus Piersig | CNC | Northeastern | X | X | StPl, Pd, OL | Unknown | |
| Arrenurus (Meg.) pseudocylindratus Piersig | CNC | Southeastern | X | X | StPl, Pd, ML, OL | Unknown | |
| Arrenurus (Meg.) pseudotenuicollis Wilson | CNC | Southeastern | X | X | Pd, ML | Culicidae | |
| Arrenurus (Meg.) rectangularis Marshall | CNC | Northeastern | X | StPl, OL | Unknown | ||
| Arrenurus (Meg.) rawsoni Marshall | CNC | Boreal | X | OL | Unknown | ||
| Arrenurus (Meg.) rotundus Marshall | Smith 1987, CNC | Great Lakes Basin | X | X | X | StPl, BPl, Pd, ML, TPl | Chironomidae |
| Arrenurus (Meg.) scutuliformis Marshall | CNC | Northeastern | X | X | X | StPl, Pd, ML, OL | Unknown |
| Arrenurus (Meg.) semicircularis Marshall | CNC | Northeastern | X | X | X | StPl, OL | Unknown |
| Arrenurus (Meg.) siegasianus Habeeb | Smith 1991b, CNC | Boreal | X | StPl | Unknown | ||
| Arrenurus (Meg.) solifer Marshall | CNC | Northeastern | X | X | StPl, Pd, ML, OL | Unknown | |
| Arrenurus (Meg.) unisinuatus Wilson | CNC | Southeastern | X | StPl | Unknown | ||
| Arrenurus (Meg.) wardi Marshall | CNC | Widespread | X | X | X | StPl, Pd, ML, OL | Unknown |
| Arrenurus (Meg.) n. sp. #1 | CNC | Southeastern | X | Hyp | Unknown | ||
| Arrenurus (Meg.) n. sp. #2 | CNC | Northeastern | X | X | BPl, Pd, TPl | Unknown | |
| Arrenurus (Meg.) n. sp. #3 | CNC | Northeastern | X | Spr | Unknown | ||
| Arrenurus (Meg.) n. sp. #4 | CNC | Northeastern | X | Spr | Unknown | ||
| Arrenurus (s.s.) americanus Marshall | CNC | Widespread | X | X | X | StPl, Pd, ML, OL | Zygoptera |
| Arrenurus (s.s.) amplus Marshall | CNC | Widespread | X | X | StPl, ML | Unknown | |
| Arrenurus (s.s.) bleptopetiolatus Cook | CNC | Great Lakes Basin | X | ML | Anisoptera | ||
| Arrenurus (s.s.) compactilis Marshall | Smith 1987, CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML | Zygoptera |
| Arrenurus (s.s.) dentipetiolatus Marshall | CNC | Great Lakes Basin | X | Pd | Unknown | ||
| Arrenurus (s.s.) drepanophorus Cook | CNC | Great Lakes Basin | X | X | X | Pd | Unknown |
| Arrenurus (s.s.) falcicornis Marshall | CNC | Southeastern | X | X | StPl, Pd, ML | Zygoptera | |
| Arrenurus (s.s.) fissicorniformis Cook | CNC | Northeastern | X | X | StPl | Unknown | |
| Arrenurus (s.s.) fissicornis Marshall | CNC | Southeastern | X | X | Pd, ML | Anisoptera | |
| Arrenurus (s.s.) flabellifer Marshall | CNC | Southeastern | X | X | StPl, Pd, ML | Unknown | |
| Arrenurus (s.s.) gennadus Cook | CNC | Widespread | X | X | StPl, Pd, ML | Unknown | |
| Arrenurus (s.s.) hungerfordi Cook | CNC | Western | X | X | Pd, ML | Unknown | |
| Arrenurus (s.s.) laticornis Marshall | CNC | Southeastern | X | StPl, Pd, ML | Unknown | ||
| Arrenurus (s.s.) magnicaudatus Marshall | CNC | Southeastern | X | X | X | StPl, Pd, ML | Zygoptera |
| Arrenurus (s.s.) major Marshall | CNC | Southeastern | X | X | X | StPl, Pd, ML | Zygoptera |
| Arrenurus (s.s.) mucronatus Lavers | CNC | Boreal | X | X | X | StPl, Pd, ML, OL | Zygoptera |
| Arrenurus (s.s.) paracascadensis Conroy | CNC | Boreal | X | X | X | StPl, Pd, ML, OL | Unknown |
| Arrenurus (s.s.) pinguisomus Cook | CNC | Southeastern | X | Pd, ML | Anisoptera | ||
| Arrenurus (s.s.) planus Marshall | Smith 1987, CNC | Great Lakes Basin | X | X | X | TPl | Zygoptera |
| Arrenurus (s.s.) pleopetiolatus Marshall | CNC | Southeastern | X | StPl, Pd, ML | Unknown | ||
| Arrenurus (s.s.) pollictus Marshall | CNC | Boreal | X | X | X | Pd | Unknown |
| Arrenurus (s.s.) pseudosuperior Cook | CNC | Southeastern | X | X | StPl, Pd, ML, OL | Unknown | |
| Arrenurus (s.s.) reflexus Marshall | Smith 1987, CNC | Boreal | X | X | X | StPl, Pd, ML | Anisoptera |
| Arrenurus (s.s.) serratus Marshall | CNC | Boreal | X | OL | Unknown | ||
| Arrenurus (s.s.) superior Marshall | CNC | Southeastern | X | X | StPl, Pd, ML | Zygoptera | |
| Arrenurus (s.s.) tetratumuli Munchberg | CNC | Northeastern | X | StPl, Pd, OL | Anisoptera | ||
| Arrenurus (s.s.) trifoliatus Marshall | CNC | Great Lakes Basin | X | X | OL | Unknown | |
| Arrenurus (s.s.) n. sp. #1 | CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML | Anisoptera |
| Arrenurus (s.s.) n. sp. #2 | CNC | Great Lakes Basin | X | StPl, BPl, Pd | Unknown | ||
| Arrenurus (s.s.) n. sp. #3 | CNC | Great Lakes Basin | X | X | StPl, ML | Unknown | |
| Arrenurus (s.s.) n. sp. #4 | CNC | Great Lakes Basin | X | X | X | StPl, ML | Unknown |
| Arrenurus (s.s.) n. sp. #5 | CNC | Northeastern | X | X | StPl, Pd, ML | Unknown | |
| Arrenurus (s.s.) n. sp. #6 | CNC | Great Lakes Basin | X | X | X | StPl, Pd, ML, OL | Unknown |