Mite Taxa Research Articles

Water mites and their use as bioindicators of water quality conditions: a Pennsylvania case study

Water mites (Acariformes: Hydrachnidia) are one of the planet's most diverse and abundant groups of aquatic arthropods. With more than 7,500 described species, water mites have been documented in nearly every known freshwater environment. In lotic systems, water mites are commonly found in fast-flowing, riffle-run stream habitats, where one square meter of substrate can contain as many as 5,000 individual mites representing more than 50 species, 30 genera, and all 8 superfamilies. Despite their widespread distribution, relative diversity, and abundance, water mites have been widely neglected in freshwater biomonitoring efforts. However, several studies across the globe have found that water mites can be used as successful bioindicators of water quality conditions. Thus, the following study provides one of the first detailed examinations of lotic water mites and their bioindicator potential in North America. We sampled water mites from sites along 'attaining' (unpolluted) and agriculturally 'impaired' (polluted) riffle-run stream habitats and compared their assemblages to other physicochemical and benthic macroinvertebrate metrics used to quantify water quality in Pennsylvania. In total, we collected 9,139 individual water mites representing 5 superfamilies, 9 families, and 14 genera from both attaining (n = 13) and impaired (n = 13) streams. Similar to other global studies, we found significant differences between the water mite assemblages of attaining and impaired streams, with attaining streams having greater richness and diversity of water mites. Our data shows that several mite taxa are associated with biological and physicochemical conditions of water quality, where some known sensitive taxa are increasingly dominant in attaining streams and less dominant in impaired streams. Conversely, some pollution-tolerant taxa dominance increases in impaired streams while sensitive taxa abundance declines. These findings illustrate that water mites vary in their sensitivity to pollution and are suitable bioindicator species whose inclusion in biomonitoring assessments will increase assessment accuracy.

Postscript: How long do Acari live? A survey of mite lifespans (part 2)

This is the second part of a survey of mite lifespans initiated last year (Zhang & Fan 2021). This series was launched to collect information on lifespan and related data across mite taxa, with the aim to stimulate more research on both the patterns and mechanisms of mite aging and lifespan (Zhang 2021). The first part covered lifespan and other life history data for Oribatida, Winterschmidtiidae, Eriophyoidea, Tydeidae, Anystidae, Cheyletidae and Blattisociidae (Zhang & Fan 2021). This part provides surveys of lifespan and related life history data for three major families: Tetranychidae (Li et al. 2022), Laelapidae (Zhang et al. 2022) and Phytoseiidae (Han et al. 2022). The third part in 2023 will complete this series.

“Tiny dancer in my hand…” 100-million-year-old case of mite flamboyance*

Parasitengona is a highly diverse and widely distributed group within the order Trombidiformes with a peculiar lifestyle. Some of them inhabit exclusively aquatic environments, while others live on land. Their larvae with significantly different morphology are parasites of invertebrates and vertebrates, while subsequent three nymphal stages and the adults alternate as inactive stases and active predators. The fossil record of Parasitengona is relatively rich compared to other mite taxa, but much remains to be discovered, particularly among inclusions in various types of fossilised resins.

Community Structure of Epilithic Moss Mites and Their Response to Environmental Factors in Different Grades of Rocky Desertification Habitats

This research has been undertaken to reveal the changes in the community structure of epilithic moss mites and the response of these mites to environmental factors under different grades of rocky desertification environment. In this study, epilithic moss mites were collected in a demonstration area for rocky desertification management in Bijie Salaxi, with the following rocky desertification grades as habitat gradients: without rocky desertification, potential rocky desertification, light rocky desertification, moderate rocky desertification, and severe rocky desertification. The differences in the number of individuals, taxa, diversity index, dominance index, richness index, evenness index, and the effects of environmental factors on moss mite communities were revealed by one-way ANOVA, correlation analysis, and redundancy analysis for different grades of these mites. The results show that a total of 11,563 epilithic moss mites were captured in the study area, belonging to three orders, 100 families, and 171 genera, with Nanorchestes and Trichogalumna as the dominant taxa. With the deepening of rocky desertification, the dominant number of Nanorchestes and Trichogalumna increased. Still, the percentage of very rare genera also decreased, and there were differences in the composition of the dominant genus taxa in different grades of rocky desertification. Different grades of rocky desertification habitats had significant effects on the diversity index and richness index of moss mite species but not on the number of taxa, individuals, dominance index, and evenness index. The overall epilithic moss mite communities in different habitats were moderately dissimilar. Air temperature and rock temperature had strong effects on each index of moss mite diversity, whereas light factors and air humidity had a weak impact on these indices. Amongst the communities, those of Scheloribates are more sensitive to rock temperature variation, while Blattisocius, Ledermuelleria and Camerobia correlate more with a light variation. Parholaspulus, Blattisocius, Camerobia, Haplochthonius, Gymnodamaeus, etc. were more sensitive to changes in air humidity. The research shows that there are differences in moss mite community structure under different rocky desertification grades, rocky desertification has caused some effects on moss mite community structure, and the use of mite dominant taxa genera can give preliminary indications of the rocky desertification environment; meanwhile, there is a specific correlation between mite taxa and habitat environment changes.

Hidden biodiversity in microarthropods (Acari, Oribatida, Eremaeoidea, Caleremaeus)

A challenge for taxonomists all over the world and across all taxonomic groups is recognizing and delimiting species, and cryptic species are even more challenging. However, an accurate identification is fundamental for all biological studies from ecology to conversation biology. We used a multidisciplinary approach including genetics as well as morphological and ecological data to assess if an easily recognizable, widely distributed and euryoecious mite taxon represents one and the same species. According to phylogenetic (based on mitochondrial and nuclear genes) and species delimitation analyses, five distinct putative species were detected and supported by high genetic distances. These genetic lineages correlate well with ecological data, and each species could be associated to its own (micro)habitat. Subsequently, slight morphological differences were found and provide additional evidence that five different species occur in Central and Southern Europe. The minuteness and the characteristic habitus of Caleremaeus monilipes tempted to neglect potential higher species diversity. This problem might concern several other “well-known” euryoecious microarthropods. Five new species of the genus Caleremaeus are described, namely Caleremaeus mentobellus sp. nov., C. lignophilus sp. nov., C. alpinus sp. nov., C. elevatus sp. nov., and C. hispanicus sp. nov. Additionally, a morphological evaluation of C. monilipes is presented.

Additions to the ptyctimous mite fauna (Acari, Oribatida) of Taiwan

The present study is based on ptyctimous oribatid mite material collected in Taiwan in 2018 and 2019. Four new species—Oribotritia chiayiensis Niedbała sp. nov. (Oribotritiidae), Phthiracarus liaoi Niedbała sp. nov. (Phthiracaridae), Plonaphacarus paraprotrusus Niedbała sp. nov. (Steganacaridae), and Notophthiracarus diamphidios Niedbała sp. nov. (Steganacaridae)—are described. Supplementary description of Acrotritia hauseri (Euphthiracaridae) is provided. A list of other identified ptyctimous mite taxa, including 10 species from six genera and five families, is presented. Four species (A. hauseri, A. mahunkai, Phthiracarus gibber, and P. parmatus) are recorded for the first time in Taiwan.

Arachnids (Arachnida: Araneae, Mesostigmata, Pseudoscorpiones) from tropical greenhouses at Rotterdam Zoo (the Netherlands), including a pholcid spider new to Europe

An inventory of arachnids was conducted in three tropical greenhouses of Rotterdam Zoo, the Netherlands. This was part of a survey in which pitfall traps, banana baits, litter samples, hand searching and beating were used to map arthropod diversity. A total of twenty spider species, one mite taxon and one pseudoscorpion species were collected. Fourteen specimens were used for COI-barcoding, which yielded two of the listed species. Four spider species were recorded for the first time for the Netherlands: Belisana ambenganHuber, 2005, Heteroonops spinimanus (Simon, 1892), Nesticella mogera (Yaginuma, 1972) and Triaeris stenaspis Simon, 1891, the first of which is also a new record for Europe and appears to be an extremely rare pholcid species. From the species found, thirteen are nonnative to the Netherlands and four of these are considered as expansive, since they have outdoor populations as well. Hand searching yielded the highest number of species, compared to the other four sampling techniques. A species saturation curve shows that in all likelihood not all species present in the surveyed greenhouses have been found during this survey.

<strong>Host plant discrimination through mobility parameters by eriophyoid mites</strong>

Eriophyoidea is a well-known mite taxon of economic importance. Due to their small size, elucidating many of their bio-ecological aspects becomes a challenge. These mites are obligatory plant feeders, with high host specificity and vagrant (free living) and non-vagrant (part or whole life cycle in a host) lifestyles. The mobility (distance walked - mm, resting time - s, and number of stops) of these mites on host and non-host plant species has been investigated. Eriophyoid species were submitted to walking tests on host and non-host plants using five vagrant species and five non-vagrant species. The walking was recorded with video tracking (ViewPoint) for ten minutes. Twenty replicates were performed for each treatment (eriophyoid species and plant). There was a difference in the behavioral response of the species studied in relation to the hosts. When the species were grouped by ecological lifestyle (vagrant and non-vagrant), non-vagrant eriophyoids presented a higher mobility (higher distance walked, less resting time) than vagrant eriophyoids on their respective hosts. There was no difference in the mobility of vagrant and non-vagrant species on non-host plants. The absence of a pattern of behavioral response among the species tested here indicates that more factors are involved in the host identification and acceptance process.

<strong>Contribution to the knowledge of oribatid mites (Acari, Oribatida) of Uganda, with description of a new species of the genus <em>Machadobelba</em> (Machadobelbidae)</strong>

A list of identified oribatid mite taxa from Uganda, including 21 species/subspecies from 17 genera and 14 families, is presented. A new species of the family Machadobelbidae is described from leaf litter. Machadobelba ugandaensis sp. nov. differs from Machadobelba barbata Sanyal, Saha & Chakraborty, 2005 and Machadobelba dispar Balogh, 1958 by the presence of one pair of lateral teeth of the rostrum, prodorsal transverse ridge between costulae and foveolate body surface. Revised generic diagnosis and an identification key to the known species of Machadobelba are presented.

<p class="Body">To the knowledge of oribatid mites (Acari, Oribatida) of the Comoro lslands

The present study is based on oribatid mite material collected from Mayotte island (Сomoro Islands, Ethiopian region) in 2011–2016. A new species of the genus Uracrobates (Oribatida, Mochlozetidae) is described; Uracrobates (Uracrobates) mayottensis sp. nov. differs from all species of the nominative subgenus by having a rounded rostrum (versus bidentate or pointed). An updated generic diagnosis and an identification key to the known subgenera and species of Uracrobates are presented. A list of all oribatid mite taxa of the Comoro Islands, including 41 species, 30 genera and 19 families, is provided. Thе genus Phauloppia and the species Edwardzetes novazealandicus are recorded in the Ethiopian region for the first time.

<p class="Body">To the knowledge of oribatid mites (Acari, Oribatida) of Samoa

A new species of oribatid mites of the family Galumnidae (Acari, Oribatida) is described from Samoa; Pergalumna enricoi sp. nov. differs from Pergalumna foveolata Hammer, 1973 by the elongate oval, transversely oriented notogastral porose areas Aa and heavily tuberculate prodorsum. An identification key to the known species of the genus Pergalumna from the Australian region is presented. A list of oribatid mite taxa of the Samoan Islands, including 77 species/subspecies from 56 genera and 29 families, is provided.

A new taxonomic placement for Scutobates Cook, 1966, with the description of a new species from French Guiana (Acari: Hydrachnidia: Hygrobatidae).

The water mite taxon Scutobates Cook, 1966 was originally described from Liberia, and treated by Cook (1966) as a subgenus of Hygrobates Koch, 1837. One of the most striking characters of Scutobates is the absence of a dorsal furrow, a ring or partial ring of unsclerotised cuticle between the dorsal plate or closely fitting platelets and the ventral shield. In the Hygrobatidae, secondary sclerotization, where the integument of the idiosoma other than the coxae, gnathosoma, genital field and glandularia bases, hardens to form sometimes extensive and merging plates can be extensive. For example, in the genus Thoracohygrobates Lundblad, 1936 the secondary sclerotization extends from the venter laterally onto the dorsum leaving a strip of membranous integument, but there is no dorsal plate development and therefore no dorsal furrow (Cook 1974). In Scutobates, the dorsum is completely sclerotized and seamlessly merges with the venter. The absence of a dorsal furrow on a completely sclerotized watermite is very rare.

Sixteen years of simulated summer and winter warming have contrasting effects on soil mite communities in a sub-Arctic peat bog

Northern peatlands are very sensitive to changes in climate. Impacts of increased temperatures on hydrology, vegetation structure and soil carbon are already well documented from northern peatlands. In contrast, effects of global warming on soil mites, and seasonal effects in particular, have received less attention, even though soil mites are an important component in ecosystems as they contribute to nutrient dynamics and decomposition. We investigated the impacts of long-term (16 years) experimental seasonal climate manipulations (summer warming, winter warming with snow accumulation, and year-round warming) on oribatid (Oribatida) and mesostigmatid (Mesostigmata) mite communities in a peat bog underlain by discontinuous permafrost, in Abisko, Northern Sweden. We found that (1) Year-round warming treatment had neither impact on life-history trait compositions nor on total abundances of oribatid mites, possibly because of opposite effects of summer and winter warming; (2) Small-bodied oribatid mites, in particular those belonging to genera Suctobelba, increased in abundance under the summer warming treatment; (3) The species richness of oribatid mites was negative affected by year-round warming; (4) Mesostigmatid mites, which were not identified to species level, were found to decrease in abundance under year-round warming. Because different mite taxa with different body sizes and diets play distinct roles in carbon and nutrient dynamics, the observed changes in mite communities may impact ecosystem functions in northern peatlands.

Edaphic characteristics and environmental impact of rubber tree plantations on soil mite (Acari) communities

The objective of the investigation was to determine the response of different taxa of mites across the land use types and demonstrate that soil mites could be used as an indicator of environmental change after the conversion of secondary forests into rubber plantations. The sampling was performed during the dry season on 12 sampling areas, consisting of four land use types: secondary forests, 7-year-old rubber plantations, 12-year-old rubber plantations, and 25-year-old rubber plantations, with three replications of each treatment. Soil cores were sampled along a 40 m transect with a steel corer. The soil mites were extracted using modified Berlese-Tullgren funnels during a 10 day period. Soil physico-chemical parameters were measured on each sampling area. The conversion of secondary forests into rubber plantations was characterized by a modification of the mean values of mite density (+103 and +262%), species richness (-11 and +32%), water content (-41 and -5%), bulk density (+6 and -3%) and soil organic carbon (-73 and -59%) respectively, after 7 and 25 years of conversion. The density of mites, species richness and soil water content increased with the aging of the rubber plantations, demonstrating an improvement in soil ecological quality and environmental conditions. These results are confirmed by the values of the Maturity Index of Gamasid mites, which increased with the increasing age of rubber plantations. In other words, the severity of environmental impact decreased with the aging of the rubber plantations and was ranked as follows: 25-year-old rubber plantations < secondary forest < 12-year-old rubber plantations < 7-year-old rubber plantations. The Maturity Indexes estimated that 25-year-old rubber plantations (0.84) and in secondary forests (0.74) are relatively similar and characterize stable habitats, which are potentially dominated by Gamasid species with K selection.

Cytological evidence for automictic thelytoky in parthenogenetic oribatid mites (Acari, Oribatida): Synaptonemal complexes confirm meiosis in Archegozetes longisetosus

Diplo-diploid parthenogenesis (thelytoky) is a widespread phenomenon in the mite taxon Sarcoptiformes, and is unusually frequent in the suborder Oribatida, where it characterizes almost 10% of extant species, including whole genera and families. Based on molecular and cytological data, terminal fusion automixis with an inverted meiotic sequence based on holokinetic chromosomes has been suggested as the reproductive mode in these mites. However, unequivocal structural evidence for meiosis is missing. The model organism Archegozetes longisetosus, a thelytokous member of the parthenogenetic family Trhypochthoniidae, was studied to gain ultrastructural insight in oocyte progression and meiotic processes. In this study, ovarian nuclear organization of its tritonymphal instar was examined by transmission electron microscopy (TEM). Numerous synaptonemal complexes were observed in the ovary, unequivocally confirming automixis (meiotic thelytoky) in oribatid mites for the first time. No recombination nodules were found. The nuclei are transcriptionally active in late prophase. Inverted meiosis is discussed as a result of the spatial arrangement of chromatid segregation.

New Oripodoidea (Acari, Oribatida) from Myanmar

The oribatid mite taxa (Acari, Oribatida), superfamily Oripodoidea, families Scheloribatidae and Caloppiidae, genera Scheloribates Berlese, 1908 and Zetorchella Berlese, 1916, and the species Zetorchella orbiculata (Wen & Zhao, 1994), are recorded in Myanmar for the first time. Two new oripodoid species are described: Scheloribates natmaensis sp. nov. (Scheloribatidae) is most similar to S. yamaeensis Nakamura, Hashimoto, Nishi, Nakamura & Fujikawa, 2015, but differs by the larger body size, narrowly triangular rostrum, clavate, rounded distally bothridial setae and longitudinal stria on the notogaster; Zetorchella taungensis sp. nov. (Caloppiidae) is most similar to Z. nortoni Ermilov, Sidorchuk & Rybalov, 2010, but differs by the larger body size, longer notogastral setae, bothridial setae shorter than humeral notogastral setae c and notogastral setae c and p1 similar in length.

Additions to the oribatid mite fauna of the Caribbean, with description of a new species of Epidamaeus (Acari, Oribatida, Damaeidae)

A list of identified oribatid mite taxa (Acari, Oribatida) from the Caribbean (mostly Lesser Antilles) partly based on a collection of the Naturalis Biodiversity Center (Leiden, The Netherlands), including 84 species from 64 genera and 35 families, is presented; of these, Grandjeania bicaudata, Scheloribates (Scheloribates) milleri, Protoribates oblongus, and Orthogalumna saeva are recorded in the Neotropical region for the first time. A new species of Epidamaeus from the Bahamas is described; E. bahamensis n. sp. differs from E. flagelloides Norton, 1979 by the morphology of notogastral setae, prodorsal tubercles Dp and parastigmatic tubercles Sa, and the absence of prodorsal tubercles Bp. Moreover, a new combination, Dyobelba palaciosi (Iglesias and Guzmán, 2012) n. comb., is proposed.

New data on the Philippine oribatid mite fauna, with a contribution to knowledge of the genus Drymobatoides (Acari, Oribatida, Mochlozetidae)

A list of identified oribatid mite taxa (Acari, Oribatida) from Capual, Luzon, Mindanao, Polillo, Samal and Samar Islands of the Philippines, including 54 species from 46 genera and 26 families, is presented; of these, 19 species, four genera and one family are recorded in this country for the first time. A new generic diagnosis for Drymobatoides (Mochlozetidae) is proposed. The taxonomic status of the mochlozetid genus Rykella is discussed, resulting in the proposal that Drymobatoides Jacot, 1936 is a senior subjective synonym of Rykella Balogh, 1962 (n. syn.) and in the following reassignments from Rykella: Drymobatoides asiaticus (Yamamoto and Aoki, 2000) n. comb., D. elamellatus (Berlese, 1916) n. comb., D. insignis (Balogh, 1962) n. comb. A new species of Drymobatoides from the Phillippines is described; D. boronganensis n. sp. differs from D. malabaricus (Clement and Haq, 1982) by the morphology of rostral, lamellar and bothridial setae, the length of the interlamellar seta, and the presence of a ventrodistal rectangular incision on leg femur II. An identification key to the seven known species of Drymobatoides is provided.

Oribatid mites (Acari: Oribatida) from Bethuadahari Wildlife Sanctuary of West Bengal, India

An annotated checklist of oribatid mite taxa from Bethuadahari Wildlife Sanctuary of West Bengal, India, is presented on the basis of a faunistic survey carried out inside the sanctuary from January, 2011 to December, 2012. A total of 44 oribatid species, belonging to 37 genera in 24 families, have been identified. The present study has also documented nine species as the new records from India. The most frequent species of this sanctuary are Protoribates (P.) magnus (Aoki, 1982), Lamellobates (L.) molecula (Berlese, 1916), Perscheloribates (P.) albialatus (Hammer, 1961) , Lamellobates (Paralamellobates) bengalensis Bhaduri & Raychaudhuri, 1968, Tectocepheus velatus sarekensis Tragardh, 1910, Multioppia radiata Hammer, 1961, and Hoplophorella cuculata (Ewing, 1909). Additionally, the most species rich families of the study area are Oppiidae Sellnick, 1937 and Scheloribatidae Grandjean, 1933.

First detection of prey DNA in Hygrobates fluviatilis (Hydrachnidia, Acari): a new approach for determining predator-prey relationships in water mites.

Up to now our knowledge of water mite diet has been fragmentary. It is derived from observations in the field and laboratory or from a few selective laboratory experiments on food choice. In the present study, we were able to detect chironomid DNA in water mite bodies for the first time using molecular methods. Prey DNA was detected in virtually all Hygrobates fluviatilis (Hygrobatidae) that were fed on chironomid larvae after a starvation period of up to approximately 1 week. From the shortest interval (1 h after feeding) to the longest period after feeding (50 h) the relative amount of detected prey DNA was significantly reduced. In addition, there was a relationship between the relative amount of prey DNA and the assumed amount of the ingested prey (classified in categories of the dead prey which reflect the increasing ingestion of the mites and the decreasing body content of the prey individuals). The results of our study indicate that similar molecular analyses will be a powerful tool for diet investigations of mites from the field on various taxonomic resolutions of prey taxa. Moreover, the results of food selection experiments from the laboratory could be compared to evidence of predation by individuals from the field. For many mite taxa, especially ones which turned out to be difficult to breed in the laboratory (e.g. by unknown diet), the new methods might enable us to gain the first ever data on diet and thus may help us to consider the role of water mites in food webs more adequately in the future.