Density Of Oribatid Mites Research Articles

Temporal variation of soil microarthropods in different forest types and regions of central Europe

Biodiversity and biomass of aboveground arthropods in central European forests continuously declined during the last decade. However, whether belowground microarthropod communities follow similar patterns has not been investigated. In this study, we compared the abundance, diversity, community composition, stability and asynchrony of oribatid mites (Acari: Oribatida) sampled in four forest types of increasing management intensity (unmanaged beech, old managed beech, young managed beech, and coniferous) at three‐year intervals from 2008 to 2020. Forest sites were replicated in three regions in southern, central and northern Germany, i.e. the Swabian Alb, Hainich‐Dün and the Schorfheide Chorin, which differ in soil characteristics and climate. We found 25 152 individuals and 121 species of oribatid mites and detected no linear decline in abundance and diversity over the last decade, suggesting that microarthropods in forest soils are buffered against land‐use effects. However, we observed that years with low winter precipitation in regions with soils that are prone to drought, resulted in significant decreases in oribatid mite densities. Community compositions remained similar across sampling years, but differed between regions and forest types, predominantly due to differences in the proportion of asexual individuals. The stability of oribatid mite communities did not decrease in managed forests and was highest in deep soils with high water‐holding capacity, which may reduce temporal variation, suggesting that soil properties are more important for the stability of oribatid mite communities than forest management. However, stability patterns were not explained by asynchrony in species fluctuations, as all communities either showed a high degree of synchrony or were not different from random. Our study highlights that the temporal dynamics of belowground communities may differ from those aboveground, and that regional differences in precipitation and soil properties are more important than forest types.

Effects of forest gap formation and deadwood enrichment on oribatid mites (Acari: Oribatida) vary between regions

Most forests in Central Europe are subject to human management, especially timber harvesting, which alters soil conditions by creating gaps in the forest canopy and reduces the availability of deadwood. However, consequences of these management practices, in particular the combined effect of gap formation and deadwood removal, have been largely neglected. Here, we investigated the abundance, diversity and community composition of oribatid mites (Acari: Oribatida) in forests where deadwood availability and gap formation were manipulated in a full factorial design (Control, Gap, Deadwood, Gap + Deadwood). Forest gaps of about 30 m in diameter were established by felling trees, which were subsequently removed (Gap) or left on site as deadwood (Gap + Deadwood). Nearby forest sites without gaps were enriched with the equal amount of felled trees (Deadwood) or left untreated (Control). Experimental treatments were established at 29 forest sites including deciduous and coniferous stands in three regions of Germany, i.e. the Swabian Alb, Hanich-Dün and Schorfheide-Chorin in the south, center and north, respectively. One year after establishment of the treatments, we sampled 10,777 individuals and 104 species of oribatid mites. Deadwood addition significantly increased the density of oribatid mites in the Hainich-Dün from 24,036 to 46,658 ind. m-². Specifically, species of Oppiidae with relatively short life cycles and high reproductive output benefited from the additional deadwood supply, resulting in shifts in community compositions between treatments with and without deadwood. By contrast, mean oribatid mite density decreased from an average of 64,083 in controls to 36,621 ind. m-² in forest gaps of the Schorfheide-Chorin and the Swabian Alb. Presumably, adverse abiotic conditions, mainly amplified drought, induced higher mortality rates in these regions. Overall, deadwood addition and forest gap formation had strong effects on oribatid mite communities, although the magnitude of each effect was similar between forest types and largely determined by regional context. This emphasizes that the effects of forest management practices on oribatid mite communities cannot be generalized across regional scales, suggesting that management plans should carefully consider regional differences.

Soil mite (Acari: Oribatida) communities in the limestone quarry of Saskhori (Gerogia)

Abstract The present publication provides a review of the soil mite (Acari; Oribatida) community’s structure and the connection between changes in environmental factors and oribatid mite diversity in the limestone quarry of Saskhori and its adjacent areas. Overall, 52 species were recorded during the study. The most abundant oribatid mite species were Steganacarus carinatus, Aleurodamaeus setosus, Xenillus tegeocranus, Ceratoppia bipilis, Oribatula tibialis, and Punctoribates punctum. Interestingly, 23 species of oribatid mites were recorded for the first time from the limestone quarry of Saskhori, and one species (Liacarus oribatelloides) was a new record for the Caucasus fauna. The following indices were analyzed: abundance (N), species diversity (S), Shannon’s diversity index (H), and Pielou’s evenness index (J’). Regarding the obtained results, the highest density of oribatid mites was recorded in the habitat with Shibliak shrubbery (332 inds/m2), while the forest habitat was characterized with the highest value for Shannon’s diversity index (2,64). In the publication, we also provide a detailed morphological description of the newly recorded species L. oribatelloides, with the respective illustration, as no figures are given in its original description.

Taxonomic and ecological structure of oribatid mites (Acari: Oribatida) of mesophilic grasslands on the Transcarpathian lowland

The article analyzes the taxonomic diversity, dominance structure, spectra of morpho-ecological types, biotope complexes and groups of oribatid mites of mesophilic grasslands on Transcarpathian lowland. Prior to our works, there were almost no studies of the oribatid communities of the studied area. The research plots located on the sorrounding areas of the city of Mukachevo and the village of Kalnyk of the Mukachevo district. Soil samples selected for 2013-2014. The geographical coordinates of the first meadow are: 48º22.79' N, 22º40.14' E, and the second one is 48º30.86' N, 22º34.65' E. The total area of the first biotope is 0.45, and the second is 37.5 hectares. In relation to the humidity of the substrate, this type of biotope is characterized by mesophilic conditions. Extraction of mites from soil was carried out using Tullgren funnel method. Permanent preparations were prepared. Identification of the specimens was carried out using a microscope (Olympus BX 51). Oribatid mites of the investigated mesophilic grasslands are represented by 26 species from 22 genera and 16 families. The families Oppiidae and Scheloribatidae are the most represented. The average density of oribatid mites of the mesophilic grasslands on Transcarpathian lowland has relatively small values (3.7 thousand specimens per m2). The dominant species include Punctoribates punctum (C. L. Koch, 1839) and Ceratozetes mediocris Berlese, 1908. They together make up 44% of the total density of oribatids. Margalef, Menkhinik, Simpson, Shannon and Berger-Parker indices were calculated. 10 morpho-ecological types of oribatid mites were found on mesophilic grasslands. Oribatids - inhabitants of small soil crevices – predominate. Representatives of five biotope complexes (euryoecic, hygrophilous, hygro-mesophilous, mesophilous and xerophilous) and four biotope groups (eurytopic, forest, forest-meadow, meadow) were identified in the structure of ecological groups of Oribatids. Mesophilous and meadow species of oribatid mites have the largest share.

The oribatid mite (Acari: Oribatida) community of a high-Andean cushion peatland in southern Peru

The oribatid mites of a high-Andean cushion peatland in southern Peru were investigated. A total of 17 oribatid mite species, belonging to eight families, could be identified in five different microhabitats. A rarefaction analysis showed a potential mite community of maximum 18 taxa per 1000 specimens for this peatland site. Ranked species abundance analysis revealed three dominant, five subdominant, three recedent, two subrecedent and four sporadic occurring taxa. The abundance of oribatid mites was 3.0 specimens cm<sup>-3</sup>(SD = 5.9) in mean. However, significantly higher oribatid mite densities were detected in muddy soils and scarcely vegetated parts in comparison to soils covered by dense vegetation cushions. The identification of deposited and damaged remains of oribatid mites is discussed.

Preventive insecticide use affects arthropod decomposers and decomposition in field crops

Insecticides use in field crops has grown increasingly prophylactic, which poses a potentially unnecessary risk to arthropod decomposers. These decomposers — including millipedes (Diplopoda), soil mites (Acari, mostly Oribatida), and Collembola — act as alternative prey for generalist predators, facilitate crop-residue breakdown, and can influence nutrient cycling. However, the abundance and activity of arthropod decomposers may be reduced by extensive prophylactic pesticide use. We conducted a three-year field experiment in no-till corn and soybean fields to assess how neonicotinoid seed coatings or broadcast applications of a pyrethroid insecticide affect arthropod decomposers and litter decomposition. Both insecticides reduced densities of arthropod decomposers and reduced decomposition of plant litter by over 10%. Neonicotinoid seed coatings reduced collembolan densities by 34% and millipede densities by 52%, while the pyrethroid significantly reduced oribatid mite densities by 24% and millipede densities by 82%. Lower mite and millipede densities correlated with slower litter loss, and decomposition was slower under neonicotinoid seed coatings and broadcast pyrethroid applications. These results indicate that perennial, widespread use of prophylactic insecticides is likely to have concerning negative effects on the availability of alternative prey, plant residue breakdown, and nutrient cycling in field crops.

Ecotoxicological assessment after the world's largest tailing dam collapse (Fundão dam, Mariana, Brazil): effects on oribatid mites.

Worldwide, environmental tragedies involving mining dam ruptures have become more frequent. As occurred a few years ago in Brazil (on 5 November 2015, in Minas Gerais state) the Fundão Dam rupture released 60million m3 of tailings into terrestrial and aquatic ecosystems. Since then, little information on the ecotoxicity of these tailings has been disclosed. In the laboratory, the acute, chronic and bioaccumulation effects of increased Fundão tailing concentrations on oribatid mites (Scheloribates praeincisus) were assessed. Additionally, the bioaccumulation of 11 trace metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) and the total density of oribatid mites found in the areas contaminated by the Fundão tailings were determined. The percentages of mite survival and reproductive inhibition were higher than 60% and 80%, respectively, in all contaminated areas with the highest concentration (100% mine tailings). Field studies showed an expressive reduction in the total density of oribatids per m-2 (up to 54 times) in the contaminated areas compared with the reference area. Metal accumulations in the field were 5.4 and 3.2 higher (for Ni and Hg, respectively) and up to two times higher (for most metals) than those in the laboratory for 42days. The mite responses to the Fundão tailings found in this study suggest long-term interference in their biological development. In this sense, we can conclude that the introduction of mine tailings onto soils tended to compromise the functionality of the mites in the ecosystem, which causes imbalances to cascade other organisms of the trophic web.

Morpho-ecological structure of oribatid mite (Acariformes, Oribatida) communities in the forest litter of recultivated areas

The study of morpho-ecological organization of oribatid mite communities (Acariformes, Oribatida) inhabiting forest litter of recultivated areas in steppe zone conditions of Ukraine was performed. The role of the forest and forest floor litter in optimization of the ecological situation on degraded lands was demonstrated. The function of environment creation by oribatids, as primary destructors of dead plant matter, supporting such ecosystem services as soil fertility improvement and nutrients turnover was highlighted. The research was performed within different stratigraphic types of bulk edaphotops in the recultivated plot of “Pavlogradskaya” colliery (Pavlograd, Dnipropetrovsk region, Ukraine) planted with red juniper (Juniperus virginiana L.). Withdrawal and collection of mites was performed with thermoeclector. For determination of the domination structure in the mite communities, the Engelmann scale was used. Adaptive (morpho-ecological) groups of oribatid mites were diagnosed by Krivolutsky. It was established that the number of species of oribatid mites in the forest litter of the studied red juniper plantation varied from 16 to 25. Average density of oribatid mites varied from 4,720 to 25,327 ind./m2. Among such morpho-ecological groups as soil surface inhabitants, small soil pore inhabitants, deep soil forms, floor litter inhabitants and unspecified forms, identified in the coniferous litter, the share of unspecified forms increased from loess-like loam type (21% of total amount) to Calcic Chernozem types with different stratigraphy (41.0%, 70.0% and 70.4% accordingly). Deep soil forms in the forest floor litter of the studied red juniper plots were not identified for any of recultivation types. The obtained results expand our understanding of the role of oribatid mites in the processes of ecological rehabilitation of disturbed ecosystems in the conditions of modern nature management.

Microhabitat distribution of arboreal oribatid mites (Oribatida), associated with the Siberian pine (Pinus sibirica) of Western Siberia.

The species composition of arboreal oribatid mites that live on Siberian pine trees (Pinus sibirica) in the forest-tundra of Western Siberia was examined, specifically of three Siberian pines from two distinct forest stands (six trees in total). Samples of litter were taken near the tree trunk, as well as samples of bark, branches and needles from the tree. In total 144 samples were taken, from which close to 5000 mites were extracted. From the arboreal samples, the mites were extract by heptane flotation. Three species of oribatid mites were recorded for the first time in Russia: Diapterobates brevidentatus, Eueremaeus trionus and Cultroribula berolina. The highest density and the highest dominance index of these species were recorded in arboreal microhabitats. Thirty-one species of oribatid mites were identified in total. No oribatid mites were recovered from the needles of Siberian pine. The density of oribatid mites did not significantly differ among various heights of the crown and trunk. The lowest density of mites was recorded on young branches without needles, whereas other branch hypothetical microhabitats did not significantly differ from each other in terms of oribatid density. The greatest Simpson diversity index was recorded in the plant litter near tree trunks. On trees, the diversity index decreased with the height of the trunk and with the distance of branch sections from the trunk. The dominant species and the degree of their dominance varied among microhabitats and forest stands. Additionally, a high level of dominance of a single oribatid species was observed on tree branches, as well as on the trunk bark located above the bole. In the two forest stands, these species were D. brevidentatus and Ameronothrus dubinini. Based on the analysis of oribatid communities, three microhabitats were identified in the first forest stand: the bole bark, the bark of the trunk above the bole, and the branches. In the second forest stand, bases of tree branches were identified as an additional microhabitat. Oribatids inhabit Siberian pine trees in the severe conditions of the forest-tundra. Arboreal oribatid communities of various microhabitats vary in their qualitative and quantitative characteristics. Also, arboreal and forest litter communities of oribatid mites vary significantly.

Parthenogenetic vs. sexual reproduction in oribatid mite communities.

The dominance of sex in Metazoa is enigmatic. Sexual species allocate resources to the production of males, while potentially facing negative effects such as the loss of well‐adapted genotypes due to recombination, and exposure to diseases and predators during mating. Two major hypotheses have been put forward to explain the advantages of parthenogenetic versus sexual reproduction in animals, that is, the Red Queen hypothesis and the Tangled Bank/Structured Resource Theory of Sex. The Red Queen hypothesis assumes that antagonistic predator—prey/ parasite–host interactions favor sex. The Structured Resource Theory of Sex predicts sexual reproduction to be favored if resources are in short supply and aggregated in space. In soil, a remarkable number of invertebrates reproduce by parthenogenesis, and this pattern is most pronounced in oribatid mites (Oribatida, Acari). Oribatid mites are abundant in virtually any soil across very different habitats, and include many sexual and parthenogenetic (thelytokous) species. Thereby, they represent an ideal model group to investigate the role of sexual versus parthenogenetic reproduction across different ecosystems and habitats. Here, we compiled data on oribatid mite communities from different ecosystems and habitats across biomes, including tropical rainforests, temperate forests, grasslands, arable fields, salt marshes, bogs, caves, and deadwood. Based on the compiled dataset, we analyzed if the percentage of parthenogenetic species and the percentage of individuals of parthenogenetic species are related to total oribatid mite density, species number, and other potential driving factors of the reproductive mode including altitude and latitude. We then interpret the results in support of either the Red Queen hypothesis or the Structured Resource Theory of Sex. Overall, the data showed that low density of oribatid mites due to harsh environmental conditions is associated with high frequency of parthenogenesis supporting predictions of the Structured Resource Theory of Sex rather than the Red Queen hypothesis.

THE DYNAMICS OF THE NUMBER OF ORIBATIC MITES ON THE PASTURES OF THE IVANOVO REGION AND THEIR INVASIBILITY OF THE MONISTIA CISTICERCOIDES

The distribution of mites on the soil surface of different types of pastures, the invasion of oribatids by monies larvae are dependent on climatic and weather conditions of the area, as well as the degree of infection with monies of the grazed livestock of ruminants. Seasonal dynamics of population density of oribatid ticks on natural and artificial pastures of two livestock farms of the Ivanovo region is studied. In soil and grass samples 5 species of shell mites were identified: Scheloribates laevigatus, Scheloribates latipes, Punctoribates punctum, Punctoribates sellnicki and Ceratozetes mediocris, cysticercoid-infested monies. Dominant species were representatives of the genus Scheloribates (65,8%), subdominant – genus Punctoribates (26,7%). The population density of oribatid mites on natural grassland pastures in may averaged 198±17,8 specimens per 1 m2 with cysticercoid monies equal to 3,39%. In June-July, the number of oribatids ranged from 249±23,5 – 298±31,2 specimens on 1 m2 at EI = 4,47–6,9% respectively. The greatest number of oribatids was found in August-September: 343±39,4 – 368±42,4 specimens per 1 m2 at EI = 8,7–9,2%. In October the population density of oribatid mites decreased to 201±28,4 individuals per 1 m2 at EI = 4,54%. Artificial (cultural) pastures, the number of oribatid mites does not exceed 108±9,3 individuals per 1 m2. The contamination of the oribatids with cysticercoids of moniesia on these pastures has not been found. The research results make it possible to assume a high degree of invasion of ruminants by moniesia when grazing them on natural meadow pastures and plan preventive measures.

Seasonal dynamics and changing sea level as determinants of the community and trophic structure of oribatid mites in a salt marsh of the Wadden Sea.

Global change processes affect seasonal dynamics of salt marshes and thereby their plant and animal communities. However, these changes have been little investigated for microarthropod communities. We studied the effect of seasonality and changes in sea level on oribatid mites in the natural salt marsh and on artificial islands in the back-barrier environment of the island Spiekeroog (Wadden Sea, Germany). Three zones of the artificial islands were filled with transplanted sods from the lower salt marsh zone and thereby exposed to three different inundation frequencies. We hypothesized that oribatid mite communities will differ along the natural salt marsh vegetation zones [upper salt marsh (USM), lower salt marsh (LSM), pioneer zone (PZ)], which are influenced by different tidal regimes. Accordingly, total oribatid mite densities declined from the USM and LSM to the PZ. Similarly, oribatid mite species compositions changed along the salt marsh transect and also responded to variations in inundation frequency in LSM on artificial islands with typical species of the USM, LSM and PZ being Multioppia neglecta (USM), Hermannia pulchella (LSM), Zachvatkinibates quadrivertex (LSM, PZ) and Ameronothrus schneideri (LSM, PZ). Oribatid mite density in the salt marsh and on the artificial islands was at a maximum in winter and spring; this was due in part to high density of juveniles, pointing to two reproductive periods. We hypothesized that oribatid mite trophic structure changes due to variations in abiotic (e.g., tidal dynamics, temperature) and biotic conditions (e.g., resource availability). Stable isotope (15N, 13C) and neutral lipid fatty acid analyses indicated that oribatid mite species have different diets with e.g., Z. quadrivertex feeding on macroalgae and fungi, A. schneideri feeding on microalgae and bacteria, and Scheloribates laevigatus and M. neglecta feeding on dead organic matter, bacteria and fungi. Overall, the results indicate that oribatid mite species in salt marshes are affected by changes in environmental factors such as inundation intensity, with the effects being most pronounced in species with narrow trophic niches and limited niche plasticity. The results also indicate that oribatid mite communities of the LSM respond little to short-term (one year) changes in inundation frequency.

Species Structure of Oribatid Mite Population (Acari, Oribatea) in the Forest Floor Litter in the Reclaimed Territories (Ukraine)

Abstract The features of the structure of the population of oribatid mites (Oribatida) as primary destructors of dead plant material that provide such ecosystem service as improvement of soil fertility are considered. Studies were performed in various stratigraphic types of artifi cial edaphotopes in the reclaimed sites of “Pavlogradskaya” query (Pavlograd, Dnipropetrovsk Region, Ukraine), which were planted with eastern red cedar (Juniperus virginiana Linnaeus). Th e amount of oribatid mite species in the forest litter of studied forest plantation varied from 16 to 25. Minimal number of species (16) and minimal population density of oribatid mites (4720 ind./m2) was established for calcic chernozem topsoil type with sand interlayer, which can be explained by lower thickness of the forest fl oor litter within this reclamation type.

Impacts of twenty years of experimental warming on soil carbon, nitrogen, moisture and soil mites across alpine/subarctic tundra communities

High-altitude and alpine areas are predicted to experience rapid and substantial increases in future temperature, which may have serious impacts on soil carbon, nutrient and soil fauna. Here we report the impact of 20 years of experimental warming on soil properties and soil mites in three contrasting plant communities in alpine/subarctic Sweden. Long-term warming decreased juvenile oribatid mite density, but had no effect on adult oribatids density, total mite density, any major mite group or the most common species. Long-term warming also caused loss of nitrogen, carbon and moisture from the mineral soil layer in mesic meadow, but not in wet meadow or heath or from the organic soil layer. There was a significant site effect on the density of one mite species, Oppiella neerlandica, and all soil parameters. A significant plot-scale impact on mites suggests that small-scale heterogeneity may be important for buffering mites from global warming. The results indicated that juvenile mites may be more vulnerable to global warming than adult stages. Importantly, the results also indicated that global warming may cause carbon and nitrogen losses in alpine and tundra mineral soils and that its effects may differ at local scale.

Плотность населения орибатид в агроценозе под воздействием различных доз минеральных удобрений

The article describes the results of studies on the influence of different doses of mineral fertilizers on armored mites – oribatid mites. It is found that the increase in population density of oribatid mites is in direct relation to the volume of the crops root system. According to the changes in the numbers of oribatid mites under the influence of different doses of mineral fertilizers and comparing population density of these areas with the controlled ones, it was noted by the authors that mineral fertilizers applied to the agricultural crops, have a positive effect on armored mites – oribatid mites.

Estudio de la comunidad de oribátidos (Acari: Oribatida) en dos parches de tala (Celtis ehrenbergiana) del sudeste bonaerense

Study of the oribatid mite (Acari: Oribatida) community from two patches of tala (Celtis ehrenbergiana) from the southern of Buenos Aires. “Talares” are xeric forests located along the coast of Buenos Aires province, Argentina. Since >400 years ago, they have been subject of a severe degradation, resulting in a fragmentary landscape of forest patches surrounded by a grassland matrix. The aims of this study were: a) to enhance the knowledge of oribatid mites in the talares, and b) to analyze the effect of habitat fragmentation on diversity, richness, abundance and structure of the oribatid mite community. I analyzed oribatids in three sites: two different-size close forest patches (big: Gr, small: Ch) and the surrounded grassland matrix (Ma) in Laguna de los Padres reserve, Mar del Plata. A total of 51 species of oribatids were identified, with similar values of richness in all sites. Oppiidae y Scheloribatidae were the families with more species. Diversity (H’) was greater in the forest patches (Gr=1.58; Ch=1.59) than in the matrix (Ma=0.91). Density of oribatid mites was higher in Gr (36500 individuals/m2); in Ch and Ma, densities were 50% and 75% lower. This global difference is a consequence of reduced population sizes in most species. According to seasonal variations, in Gr there were more “ubiquitous” species (20) than in Ch y Ma (10). Summarizing, the community of oribatid mites were primarily conditioned by the type of environment (grassland vs. forest), with similar distribution patterns of species but with a marked seasonality in the grassland matrix. Among forest patches, area did affect oribatid mites density through a reduction in most population sizes. The evaluation of the fragility of these populations could be a starting point to undertake conservation programs.

Temporal fluctuations in oribatid mites indicate that density-independent factors favour parthenogenetic reproduction

We investigated the oribatid mite density, community structure and the percentage of parthenogenetic individuals in four different forest types across three regions in Germany in 2008 and once again in 2011. We compared temporal (inter-annual) fluctuations in population densities between sexually and parthenogenetically reproducing species of oribatid mites. We hypothesized that population densities in parthenogenetic oribatid mite species fluctuate more than in sexual ones. Further, we expected species composition and dominance of parthenogenetic species to differ between forest types and regions. Oribatid mite community structure did not differ between years but varied with forest type and region, indicating low species turnover in time. As hypothesized, temporal fluctuations were more pronounced in parthenogenetic as compared to sexual species. The percentage of parthenogenetic individuals was significantly higher in coniferous than in beech forests and significantly higher in Schorfheide-Chorin than in Hainich-Dün and Schwäbische Alb. The results indicate that parthenogenetic species flourish if populations are controlled by density-independent factors and dominate at sites were resources are plentiful and easily available, such as coniferous forests, and in regions with more acidic soils and thick organic layers, such as Schorfheide-Chorin. However, historical factors also may have contributed to the increased dominance of parthenogenetic species in the Schorfheide-Chorin, as this region was more heavily glaciated and this may have favoured parthenogenetic species. Overall, our study supports the hypothesis that parthenogenetic species benefit from the lack of density-dependent population control whereas the opposite is true for sexual species.

ORIBATID MITE INFESTATION IN THE STORED CHINESE HERBAL MEDICINES.

to investigate the breeding status of oribatid mites and its related biological traits in the stored traditional Chinese herbal medicines. sixty-three sorts of stored traditional Chinese herbal medicines of root and stem origins were collected from Huainan City in Anhui Province. The mites were isolated by Shakesieve and Tullgren, and identified and counted under the light microscope. thirteen samples in 63 were infested with the oribatid mites, which accounted for 21.67 %(13/60). A total of 11 species of oribatid mites, belonging to 6 families, were found in the 13 samples, and the most abundant species were Scheloribates laevigatus (36.19%), Scheloribates latipes (28.35%) and Trhypochthpnius japonicus (19.72%). The average breeding density of oribatid mites was about 4.51 individuals/g; the index of species richness, the diversity index, and the evenness index of species were 1.14, 1.581, and 0.212, respectively. oribatid mites were found in stored Chinese herbal medicines from Huainan city in Anhui province of China, suggesting that the conventional storage and processing technique should be improved in order to ensure the quality and safety of the herbal medicines.

Oribatid mite communities along an elevational gradient in Sairme gorge (Caucasus).

Many aboveground animals and plant communities have been studied along elevational gradients whereas studies on soil animals are scarce. Here, we studied oribatid mite community distribution along an elevational gradient from 600 to 2200 m in forest ecosystems of the Western Lesser Caucasus Mountains in Georgia. Overall, 86 oribatid mite species were found at the study sites. Oribatid mite densities were generally low (~9800 ind./m(2)), and 74% of all species reproduced sexually indicating that resource conditions at the study sites are generally poor. Oribatids mainly comprised Brachypylina (76%), Mixonomata (13%), Desmonomata (6%) and Enarthronota (5%). Oribatid mite community structure changed along the elevational gradient and the changes correlated with temperature, pH, litter thickness and density of the herb layer. The dominance of sexually reproducing taxa and low overall abundance indicate that the studied elevational gradient is characterized by poor resource conditions for soil microarthropods. Oribatid mite species richness and density declined with elevation suggesting that decreasing temperature in concert with resource limitation is a main driver of oribatid mite communities whereas stochastic factors (such as mid-domain effects) are of minor importance.

Oribatid mite communities on the bark of dead wood vary with log type, surrounding forest and regional factors

Dead wood is a crucial component of natural and semi-natural forest ecosystems. It is of eminent importance as habitat for a variety of animal species but its importance for microarthropods, a diverse group of small forest animals, has been little studied. We investigated how oribatid mite density, species richness, community structure and the proportion of parthenogenetic individuals on the bark of dead wood are affected by log type (beech, oak) and surrounding forest type (deciduous, coniferous) in three regions in Germany (Schorfheide-Chorin, Hainich-Dün, Schwäbische Alb). Additionally, we analyzed the trophic structure of oribatid mites from the bark of dead wood in one region (Hainich-Dün) using stable isotope ratios (15N/14N, 13C/12C). Oribatid mite richness and community structure were significantly affected by log type, forest type and region. Oribatid mite communities comprised mainly soil and arboreal species but only few dead wood specialists indicating that dead wood in an early stage of decay functions as transitory habitat rather than specific microhabitat. However, some oribatid mites likely are adapted to dead wood as habitat by living phoretically on bark beetles (e.g., Siculobata leontonycha) or endophagous in fungi associated with dead wood (e.g., juvenile Carabodes species). The proportion of parthenogenetic oribatid mite individuals was rather low (∼8%) suggesting that oribatid mites on dead wood predominantly rely on living food resources resembling arboreal communities but not those in soil. Natural variations in stable isotope ratios indicate that oribatid mites on the bark of dead wood span at least three trophic levels including lichen feeders, moss feeders, decomposers and fungal feeders with fungal feeders dominating.