The ontogeny is known for few species of the oribatid mite genus Hermannia (Hermanniidae). Here, we present the morphological ontogeny, distribution and some descriptive population parameters of Hermannia reticulata Thorell, 1871 collected from throughout Arctic Svalbard. All instars of Herm. reticulata are stocky, as other species of Hermannia Nicolet, 1855 for which ontogeny is known. They have gastronotal setae of similar form and ontogeny (12 pairs in the larva and 16 pairs in the nymphs and adult) and the same is true of prodorsal setae, except in Herm. reticulata the sensillus is clavate, whereas in the other species it is setiform. In Herm. reticulata, setae of the anal segment are delayed to the tritonymph as in most other studied species, whereas they first appear in the deutonymph in Herm. gibba. Studied species also differ by the number of epimeral setae in the nymphs and adult and the ontogeny of leg setae. Hermannia reticulata is a holarctic species and mainly occurs in the circumpola...

Morphological ontogeny, distribution and descriptive population parameters of Hermannia reticulata (Acari: Oribatida: Hermanniidae), with comments on Crotonioidea

In this study, the morphology, distribution, ecology, stage structure and sex ratio of the Arctic oribatid mite Oribatella arctica (Thor, 1930) were investigated. The juveniles of this species are similar to those of other species of Oribatella Banks, 1895, possessing mostly long and barbed prodorsal setae, long and barbed gastronotal setae in the larva and long, barbed peripheral gastronotal setae in the nymphs. The larva of O. arctica differs from that of most other Oribatella species principally by the shape of the sensillus and the length of seta le. Nymphs differ chiefly by the number and shape of some central setae (c1 and d-series) on the gastronotum and the attachment of the exuvial scalps of previous instars to the gastronotum. All nymphs of O. arctica have central setae c1, da and dm short and smooth, whereas the presence and shape of seta dp varies between nymphal stages (it can be long and barbed, short and smooth, alveolar or absent). Oribatella arctica nymphs rarely carry the exuvial scalps ...

Morphology, distribution and certain population parameters of the Arctic mite Oribatella arctica (Acari: Oribatida: Oribatellidae)

The oribatid soil mite Oppia nitens C.L. Koch, 1836, is a model microarthropod in soil ecotoxicity testing. This species has a significant role in supporting soil functions and as a suitable indicator of soil contamination. Despite its significance to the environment and to ecotoxicology, however, very little is known of its biology, ecology, and suborganismal responses to contaminants in the soil. In the present review, we present detailed and critical insights into the biology and ecology of O. nitens in relation to traits that are crucial to its adaptive responses to contaminants in soil. We used a species sensitivity distribution model to rank the species sensitivity to heavy metals (cadmium and zinc) and neonicotinoids (imidacloprid and thiacloprid) compared with other standardized soil invertebrates. Although the International Organization for Standardization and Environment and Climate Change Canada are currently standardizing a protocol for the use of O. nitens in soil toxicity testing, we believe that O. nitens is limited as a model soil invertebrate until the molecular pathways associated with its response to contaminants are better understood. These pathways can only be elucidated with information from the mites' genome or transcriptome, which is currently lacking. Despite this limitation, we propose a possible molecular pathway to metal tolerance and a putative adverse outcome pathway to heavy metal toxicity in O. nitens. Environ Toxicol Chem 2019;38:2593-2613. © 2019 SETAC.

https://setac.onlinelibrary.wiley.com/doi/epdf/10.1002/etc.4574

Oppia nitens C.L. Koch, 1836 (Acari: Oribatida): Current Status of Its Bionomics and Relevance as a Model Invertebrate in Soil Ecotoxicology.

The Oribatida is the most abundant and diverse group of mites and one of the most abundant groups of invertebrates in bogs, important for the decomposition of organic matter. These mites are relatively poorly studied in bogs and their seasonal dynamics have never been investigated in detail throughout the year. The study was performed on the periphery of a bog pond located in north-eastern Poland during four seasons. The analyses were based on 25,128 mites comprising 24,393 Oribatida from 66 species. The second most abundant group was Prostigmata, followed by Mesostigmata. The density of mites and of Oribatida reached a maximum in autumn (ca. 90,000 individuals/m2), and was nearly two-fold greater than in other seasons. In autumn, spring and summer the oribatid communities were dominated by the aquatic genus Limnozetes, while in winter these mites were replaced by species with lower water demands (e.g. Liochthonius alpestris, Mainothrus badius, Scheloribates laevigatus) or eurytopic ones (e.g. Oppiella nova). Oribatida reproduced in all seasons with the greatest proportion of juveniles (25%) observed in winter. Two species, Liacarus acutus and Dissorhina ornata peloponnesiaca are reported for the first time for the Polish fauna; both were found only in one season showing that sampling throughout the year is important to determine biodiversity.

Seasonal Dynamics of Oribatid Mites (Acari, Oribatida) in a Bog in Poland

In this study, the complete ontogenetic development of morphological traits in Phenopelopidae was investigated on the base of juvenile and adult specimens of Eupelops hirtus (Berlese, 1916) and Peloptulus phaenotus (CL Koch, 1844) and literature. The juveniles of Eupelops Ewing, 1917, Peloptulus Berlese, 1908 and Propelops Jacot, 1937 show plicate integument and a dorsoventrally flattened hysterosoma, with short setae c1, c3 and of d-series on the gastronotum, which seem to be typical of Phenopelopidae. However, the juveniles of Eupelops and Peloptulus have some or all marginal setae on the gastronotum longer and thicker than other setae, at least one setal pair on the posterior part of gastronotum (h1 in larva and h3 in nymphs), whereas those of Propelops have these setae long or short. The juveniles and adults of Eupelops and Peloptulus differ distinctly from those of Propelops in the type of subcapitulum and chelicerae; the two former genera have the subcapitulum secondarily anarthric and the chelicera...

Ontogeny of morphological traits in Phenopelopidae (Acari: Oribatida)

The effect of different diet on Oppia denticulata was studied during a 4-month laboratory experiment, based on daily observations This species is known as microphytophagous (ie feeding on bacteria and/or fungal hyphae and/or algae), like other species of Oppiidae, but our observations show its wider diet We tested 11 types of food, including homogenous diet [green algae, lichens, fungi (dry yeasts, Trichoderma viride, Penicillium chrysogenum), nematodes], and combined diet [green algae and nematodes, lichens and nematodes, dry yeasts and nematodes, T viride and nematodes, P chrysogenum and nematodes] The basic population parameters (fertility, mortality, sex ratio), time of development, population growth in four months and body length were compared between all groups Observations on biology of O denticulata were also made The most favourable diet for O denticulata was a combination of T viride and nematodes, which allowed the highest population growth (about 50 times higher than the least favourable food, a combination of P chrysogenum and nematodes), due to highest fertility and shortest development Good population parameters and largest size were obtained on yeasts (served alone or with nematodes) This species did not do well on P chrysogenum, probably because it produces penicillin

https://bioone.org/journals/systematic-and-applied-acarology/volume-22/issue-5/saa.22.5.12/The-effect-of-different-diet-on-life-history-parameters-and/10.11158/saa.22.5.12.pdf

The effect of different diet on life history parameters and growth of Oppia denticulata (Acari: Oribatida: Oppiidae)

In this study the variability of the external morphology of Eueremaeus Mihelcic, 1963 was investigated, in the light of the ontogeny of Eueremaeus oblongus (C.L. Koch, 1835), Eueremaeus intermedius Mihelcic, 1963, Eueremaeus silvestris Forsslund, 1956 and Eueremaeus travei Mihelcic, 1963 and the literature. Morphological variability occurs in all species and includes mainly the presence and size of foveae in different parts of body of the juveniles, shape of femora I–IV of nymphs and shape of prodorsal lamellar costulae and tubercles between the bothridia of the adults. Eueremaeus intermedius and Eu. silvestris are considered by some authors as synonyms of Eu. oblongus, but in the light of our observations these species differ by the morphology of the juveniles and adults from Eu. oblongus, so we provisionally reject these synonyms until the type or topotypic material of these species can be compared. All these species are relatively similar in the larva, and differentiation of their morphology increases ...

Variability of external morphology of Eueremaeus Mihelčič, 1963 (Acari, Oribatida, Eremaeidae) in the light of ontogeny of four species

Oribatid mites are mainly terrestrial animals, but some are aquatic, including all species of the genus Hydrozetes (Hydrozetidae). They have often been recorded in abundance on the water's surface, while their presence in the benthic zone is poorly documented. A litterbag experiment was carried out in Coutos Lake, a shallow temporary lake in Southeast Brazil, in order to study the ecology and biology of Hydrozetes paulista. This mite species greatly dominated the benthic invertebrate community (82%), and at the end of the experiment it reached a density (652 individuals per 1 g of dry substrate) higher than that ever previously reported before for any Hydrozetes species. This density was correlated with some water parameters, stronger with conductivity, and less with temperature. The adults dominated in the stage structure (constituting over 80% of sample population), but the participation of the juveniles increased with the time. Larvae were first noticed on 25th day of experiment and after that...

Mariola Słowikowska

Papers

The effect of different diet on life history parameters and growth of Oppia denticulata (Acari: Oribatida: Oppiidae)

Variability of external morphology of Eueremaeus Mihelčič, 1963 (Acari, Oribatida, Eremaeidae) in the light of ontogeny of four species

Ecology and biology of Hydrozetes paulista (Acari: Oribatida) in the benthic zone of a temporary lake in Brazil