Diversity Of Mites Research Articles

Inclusion of juvenile stages improves diversity assessment and adds to our understanding of mite ecology - A case study from mires in Norway.

Arachnid orders, Mesostigmata, Trombidiformes, and Sarcoptiformes, commonly known as 'mites', are abundant in mires, both as adults and as juveniles. However, due to the challenges of identification, the juvenile forms are often excluded from analyses. This is the first study in mires that included all three mite orders identified to the species level, including juvenile instars. We aimed to compare how diversity and the response to ecological variables differed if only the adults (ad) vs. the total number of specimens (ad+juv) are considered. Samples of 20 Sphagnum species (five subgenera) were collected and mites were extracted using Berlese funnels. Overall, nearly 60,000 mites were analyzed; of these Mesostigmata made up 1.87% of the total, Trombidiformes -0.27%, and Sarcoptiformes -97.86%. The study revealed 154 species (33 Mesostigmata, 24 Trombidiformes, and 97 Sarcoptiformes), the highest diversity of mites ever reported from mires. The inclusion of juveniles increased observed species richness by 6%, with 10 species (one Mesostigmata, six Trombidiformes, and three Sarcoptiformes) represented only by juvenile forms. Seventeen species are new to Norway (four Mesostigmata, one Sarcoptiformes, and 12 Trombidiformes, including five undescribed species of Stigmaeidae and Cunaxidae). Four of these were represented in the samples only by juveniles. Including the juveniles explained a greater amount of the variability of Trombidiformes (explanatory variables account for 23.60% for ad, and 73.74% for ad+juv) and Mesostigmata (29.23% - ad, 52.91% - ad+juv), but had less of an impact for Sarcoptiformes (38.48% - ad, 39.26% - ad+juv). Locality, Sphagnum subgenus and species, wetness, and trophic state significantly affected the mite communities and should be taken into consideration when studying mires. Since juvenile stages contribute significantly to mite diversity in mires, they should also be included in mite studies in other habitats.

Trophic links between soil predatory mites and nematodes as a key component of conservation biocontrol

Biological control is an important ecosystem service for soil and plant health and has been successfully exploited, especially through augmentative biological control programs, for above-ground agricultural pest control often using predatory mites of Mesostigmata. Similar success has not been achieved for below-ground systems. Predatory mites are an important part of soil food webs, in which they have a regulatory impact. While this is mediated by the predator on the prey, recent studies suggest that biocontrol efficiency can be enhanced in the mid to long term for generalist predators by the presence of complementary prey. In below-ground systems, nematodes are an important food source and numerous species of predatory mites in soil may prefer them. Thus, nematodes are a viable and accessible alternative prey for these natural enemies. Our aim was to review the studies on mite-nematode trophic interactions and how these interactions affect the regulatory activity of predatory mites in soil. We found ca. 170 publications reporting a predator-prey interaction. The majority of the studies were conducted in the laboratory (149 studies), but important correlations between nematode and mite densities have been observed in greenhouses and in the open field. Most reports involved free-living nematodes (FLN), followed by plant-parasitic nematodes (PPN) and finally animal-parasitic nematodes (APN). These reports are for Astigmatina, Endeostigmata, Prostigmata, Oribatida (non-Astigmatina) and Mesostigmata, the latter group being the one in which most nematophagous species are known. The family with the most reports of nematophagy is Ascidae (46 species), followed by Macrochelidae and Laelapidae (both with 30 species). In many cases, a positive effect on reproductive parameters and developmental times of mite species has been observed with a nematode-based diet, especially FLN. Although still scarce, studies on species of Laelapidae, Macrochelidae, Parasitidae and Rhodacaridae have shown that supplementing FLN in the diet can favor reproduction and development, even though preference may change at different stages of development. Also, recent studies have shown that some organic amendments can increase the density and diversity of mites, FLN or both, enhancing top down forces by predatory mites in the soil food web. Although some steps have been taken, future studies should focus on transferring laboratory research to field and semi-field conditions. For this, a multidisciplinary approach is essential.

Exploring the diversity and host association of tarsonemid mites in West Bengal, a highly biodiverse state of Eastern India

The family Tarsonemidae is an extremely diverse assemblage of heterostigmatid mites which include phytophagous, fungivorous, detriphagous, algivorous and insect parasitic species living in various terrestrial, arboreal, subcortical or nidicolous habitats. Many of these mites pose a serious threat to global agriculture due to their direct feeding on crop plants or indirect transmission of disease-causing bacterial or fungal spores to healthy plants. For instance, Polyphagotarsonemus latus may reproduce year-round in all tropical and subtropical habitats and feed on more than 60 different plant families. Steneotarsonemus species, such as S. spinki and S. subfurcatus, attack rice and can significantly reduce the harvest, S. ananas attacks pineapple, and S. laticeps targets lilies. In temperate forests of the Northern Hemisphere, several Tarsonemus species phoretic on curculionid beetles transfer lethal fungal spores on healthy pine trees, while some other species pose a real hazard to cultivated mushrooms and stored products.

The impact of 12 years of biological control on soil microbiome and microfauna composition and functions in tea plantations

Synthetic pesticides were introduced to China in the 1940s and have become essential to increasing crop yield. They are now commonly applied across all agricultural landscapes. However, little is known about how the long-term pesticide use is affecting belowground communities and what impact pesticide residues are having on soil health. We investigated how pest management practice influence soil biota and overall yield. Soil samples were compared across tea farms that had different levels of pest management strategies: biocontrol, pesticide use, unmanaged over 12 years. DNA was extracted from the bulk soil underneath the canopy and subjected to 16S rRNA, 18S rRNA genes, ITS amplicon sequencing, qPCR quantification of the community and functional genes involved in the N-cycle. Additionally, the abundance and diversity of soil mites were recorded using traditional methods. The results highlighted that there were significant differences in edaphic properties including total nitrogen, total organic carbon, pH, phosphorus and levels of several pesticides across all treatments. Overall, there were distinct microbial communities associated with each treatment and diversity patterns were significantly influenced by management strategies. Across all gene regions, there was variation in the relative abundance of dominant taxa across treatment. Management influenced the abundance of N-cycling genes with an increased abundance of amoA and nirK in biocontrol and unmanaged farms. Interestingly, we found an increased abundance of fungal pathotrophs in the pesticide treatment. We also found that mite compositions and densities were different across all management strategies. The overall mite density and that of Rhodacaroidea were highest in the pesticide treatment and lowest in the unmanaged farm soil. This work aims to improve our understanding of pest management strategies from a soil biota point of view, to enhance soil health and to promote sustainable tea productions.

Comparative diversity of the Uropodina (Acari, Gamasida) inhabiting poultry manure in southeastern Brazil

Species in the cohort Uropodina include a great diversity of free-living mites, which inhabit soil, leaf litter and manure. These habitats present favorable microclimatic aspects for colonization and succession of several species of mites, with different niches occupied over time. For poultry manure, many weeks of manure accumulation are necessary for there to be sufficient colonization by predatory and decomposing arthropods, including mite species, and for the formation of complex food webs for ecological stability. The knowledge of manure mite fauna in Brazil is hampered by the great diversity of species and the lack of specialists. In the State of São Paulo, there are few known species of edaphic and manure mites from the cohort Uropodina. This study presents taxonomic and some comparative distribution data about uropodids in poultry manure in the State of São Paulo. The manure was collected in poultry farms in Mogi-Guaçu, SP (1,800 kg) in July 2022. The mites were extracted by Berlese-Tullgren method over an eight-day period and preserved in 70% alcohol. The mites were counted and Uropodina identified by visual observation for clarification and preparation of slides in Hoyer’s medium. The mite specimens were compared with the mites previously collected in manure from a laying farm in Santa Cruz da Conceição, SP in July 2001 and July 2002. Two morphospecies of Thrichouropoda were identified in the samples from Mogi-Guaçu. The mites obtained in Santa Cruz da Conceição, SP had representatives in the genera Uroseius, Uroobovella and Thrichouropoda, with four morphospecies identified. The variation in distribution and diversity of uropodids in the manure of both poultry farms suggest that instabilities regarding the accumulation of manure, management in these properties, environmental changes over the years and factors intrinsic to the locations, could affect the uniformity of collections in these areas. The uropodids from this study were deposited in the Collection of Arthropods of Medical and Veterinary Importance (IB-CPAMV), Laboratory of Animal Parasitology, Biological Institute of São Paulo.

The diversity and distribution of oribatid mites in high altitudinal ecosystems of Great and Lesser Caucasus

The aim of our investigation was to study the community composition and distribution of oribatid mites in high altitudinal ecosystems of Great and Lesser Caucasus mountains.

Mites associated with early decomposition stages of pigs (Sus scrofa domestica) in Texcoco, Mexico

Mites can be found in various habitats, they are sensitive to climate variation and disturbance of ecosystems. Many mites are phoretic on insects that are associated with plant and animal decomposition, therefore they can provide relevant information to forensic investigations, such as post-mortem time, causes of death, or temporal and geographical conditions of the place where the body was found. The study of mites at a crime scene or as part of the evidence that can be collected has very important functions. For example, mites can be used to determine cases of food contamination, to track shipments of illegal substances, as well as in investigations of murders, missing persons or cases of negligence. Mites are always present, even in environments where the presence of insects is scarce. Despite this importance, studies on the diversity of mites associated with decomposing bodies are scarce, and work on the matter is just beginning in Mexico.

Mite conservation: which species should we care about—and should we care at all?

The enormous diversity of mites, some of which depend upon a single host species, coupled with threatened species and environments, means that some must be endangered or even extinct. But how do we identify an endangered mite species, recognise which species are at greater risk of extinction, and determine how they can be incorporated in conservation efforts?

The phylogeny of acariform mites: what brought us here and perspectives

Recent years have witnessed an increasing availability of DNA sequence data from acariform mites. However, compared to Hexapoda, a clade to which the mite diversity rivals, the amount of acariform molecular data estimated in cells in supermatrix alignments (Fig. 1) is lagging behind by approximately one decade, since insect datasets reached 107 cells in 2010 (reviewed in Kjer et al. 2016).

Global mite diversity is in crisis: what can we do about it?

Since the 1970’s, biodiversity, conservation and ecology journals have published increasing numbers of reports of major, widespread losses of the diversity and abundance of plants, vertebrates and invertebrates, mostly insects, especially in tropical regions. Mites make a major contribution to global ecosystem services and ecological functioning. Reports on diversity and abundance losses among mites, including ticks, have appeared more recently. The huge problems of population decline and direct extinction among free-living invertebrate species across the world are compounded by the host dependency of enormous numbers of other invertebrate species, which puts them at serious risk of secondary endangerment and co-extinction. They include huge numbers of mite species in symbiotic relationships, including phoretic and parasitic relationships, and the highly host-specific, phytophagous eriophyoids. The destruction and degradation of terrestrial and aquatic ecosystems and habitats across the world, especially for agricultural expansion and intensification, are the major causes of biodiversity loss, with climate change, pollution, overexploitation, invasive species and pesticide use among other contributors. Measures and activities that would substantially contribute to saving the great majority of the world’s remaining biodiversity include the protection of all remaining areas of natural and semi-natural habitat, especially the subtropical and tropical forests, with the 36 global biodiversity hotspots an absolute priority; habitat restoration with local species; higher global soil carbon levels; rapid transition from fossil fuel use to renewable energy sources to stop climate change; minimization of pollution; universal education and social justice; a lower human population; and sustainable use of global resources. The rapid implementation of these and other practical measures at the local, national and global scales is essential to ensure the long term survival of the vast majority of biodiversity, including mite species.

Global patterns and drivers of herbivorous eriophyoid mite species diversity

AbstractAimEnvironmental drivers and host richness play key roles in affecting herbivore diversity. However, the relative effects of these factors and their effects on lineages characterized by high host specificity are not well known. In this study, we explored the extent to which contemporary climate, Quaternary climate change, habitat heterogeneity and host plants determine the species richness and endemism patterns of herbivorous eriophyoid mites.LocationGlobal.TaxonEriophyoid mites (Acari: Eriophyoidea).MethodsWe compiled a dataset comprising 4278 eriophyoid mite species from 22,973 occurrence sites based on a comprehensive search of the published literature and the Global Biodiversity Information Facility (GBIF) as a basis for predicting their global distribution patterns. We measured the association of environmental variables and host plant richness with species richness and endemism of eriophyoid mites through multiple regression analyses using a simultaneous autoregressive (SAR) model, an ordinary least squares (OLS) model and a random forest model. We examined the direct and indirect effects of these environmental variables and the host plant richness on eriophyoid mite diversity using structural equation models (SEMs).ResultsThe species richness and endemism patterns of eriophyoid mites are concentrated in temperate regions. Contemporary climate, Quaternary climate change, habitat heterogeneity and host plants all significantly affected eriophyoid mite richness, while Quaternary climate change, habitat heterogeneity and host plants contributed to the eriophyoid mite endemism. Abiotic factors indirectly influenced the species richness and endemism of eriophyoid mites, via biotic factors—host plants.Main ConclusionsThe species richness and endemism of eriophyoid mites peak in temperate regions, opposite to the patterns of plants and some other organisms. Complex interactions among biotic and abiotic factors shape the current eriophyoid mite species diversity.

Preliminary Study on Species Diversity and Community Characteristics of Gamasid Mites on Small Mammals in Three Parallel Rivers Area of China.

(1) Background: Gamasid mites are a large group of arthropods, and some of them are of medical importance. Besides directly biting humans and causing dermatitis, some gamasid mites are the vector of rickettsialpox and potential vector of hemorrhagic fever with renal syndrome (HFRS). The Three Parallel Rivers Area of China is one of the hotspots of biodiversity research in the world, with complicated topographic landforms, different types of vegetation, special elevation gradients and high biodiversity. (2) Methods: Species richness (S): the Shannon-Wiener diversity index (H), Simpson dominance index (D) and Pielou evenness index (E) were used to analyze the basic community structure. The β diversity (Cody index) was used to reflect the diversity difference between any two adjacent elevation gradients. The method based on Preston's lognormal model for species abundance distribution was used to estimate the total number of gamasid mite species. (3) Results: A total of 3830 small mammal hosts captured from the nine survey sites were identified as 44 species, 27 genera and nine families in five orders. Apodemus chevrieri, Eothenomys miletus and A. draco were the dominant host species with a total constituent ratio Cr = 52.037%. From the body surface of the hosts, 26,048 gamasid mites were collected and identified as 10 families, 21 genera and 82 species (excluding 847 unidentified specimens) with high species richness (S = 82) and diversity (H = 2.33). The three dominant mite species were Dipolaelaps anourosorecis, Laelaps nuttalli and L. echidninus, with a total Cr = 64.46% (16,791/26,048). There are significant differences in the species composition, species diversity and dominant species of gamasid mites on different hosts. The species diversity of the mite community fluctuated greatly in different elevation gradients. The highest peaks of species richness and β diversity appeared at altitudes of 3000-3500 m (S = 42) and 1500-2000 m (β = 17.5), respectively. The species abundance distribution of the mites was successfully fitted by Preston's lognormal model with S^(R)=19e-[0.22(R-0)]2 (α = 0.22, R2 = 0.9879). Based on fitting the theoretical curve by Preston's model, the total number of gamasid mite species was estimated to be 153 species. (4) Conclusions: Gamasid mites on small mammals are abundant with complex community structures and high species diversity in the Three Parallel Rivers Area of China. There is an apparent community heterogeneity of the mites on different hosts and in different environments.

Arthropods associated with the lychee erinose mite, Aceria litchii (Acari: Eriophyidae) on lychee trees in Minas Gerais, Brazil.

Lychee fruit production (Litchi chinensis) has been threatened in many regions of the world where the presence has been reported of the litchii erinose mite, Aceria litchii (Keifer). This study aims to identify the arthropod community associated with A. litchii on lychee plants in Minas Gerais, Brazil, and to seek for potential natural enemies associated with this mite pest in this region. We sampled lychee leaves infested with A. litchii in commercial and non-commercial lychee orchards during seven consecutive months, covering the dry and wet seasons of the year. Arthropods found in association with A. litchii on lychee leaves were collected and identified. The results indicate that a great diversity and abundance of mites and hexapods are associated with A. litchii. A total of 985 and 1872 specimens of mites were identified in commercial and non-commercial areas, respectively, belonging to the families Cheyletidae, Cunaxidae, Eupodidae, Iolinidae, Stigmaeidae, Phytoseiidae, Tarsonemidae, Tenuipalpidae, Tetranychidae, Tryophtydeidae, Tuckerellidae, Tydeidae, Winterschmidtiidae and Xenocaligonellidae and the suborder Oribatida. Among them, Phytoseiidae was the most abundant and diverse family with a total of 11 species identified, in which Phytoseius intermedius was the most abundant predatory mite species collected. Minor specimens of hexapods were also been, belonging to the orders Collembola, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Psocoptera and Thysanoptera. The presence of a high community of predatory mites in association with A. litchii deserves attention and our results indicate that studies to test the potential of these species and the adoption of management practices that enhance this ecological service must be carried out to achieve satisfactory control of the lychee erinose mite in lychee plants.

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.

Environmental factors affecting water mites (Acari: Hydrachnidia) assemblage in streams, Mangde Chhu basin, central Bhutan

Water mites were sampled from 15 tributary streams of Mangde Chhu river in Zhemgang and Trongsa districts, Central Bhutan in pre-monsoon (April–May) and post-monsoon (October–November) of 2021. A total of 802 individuals were collected belonging to seven families and 15 genera. The accumulation curve suggests that the sampling efforts were adequate to give a proper overview of genera composition for elevations 500–2,700 m. Eleven genera—Aturus, Kongsbergia, Woolastookia, Atractides, Hygrobates, Lebertia, Piona, Sperchonopsis, Monatractides, Pseudotorrenticola and Testudacarus—and five families—Aturidae, Hygrobatidae, Lebertiidae, Pionidae, and Protziinae—are new records for Bhutan. Independent sample t-tests of genera richness (t, (26) = 0.244, p = 0.809); genera evenness (t, (26) = 0.735, p = 0.469); Shannon diversity index (t, (26) = 0.315, p = 0.755) and dominance (t, (26) = -0.335, p = 0.741) showed no significant differences between pre- and post-monsoon assemblages. Species abundance was also not significantly different (t, (28) = -0.976, p = 0.330). Principal component analysis indicated that the diversity of water mites is negatively associated with several environmental variables including chloride (r = -0.617), ammonia (r = -0.603), magnesium hardness (r = -0.649), total hardness (r = -0.509), temperature (r = -0.556), salinity (r = -0.553), total dissolved solids (r = -0.509) and electrical conductivity (r = -0.464). Diversity was positively correlated with altitude, mainly caused by the higher Palaearctic genera diversity. Similarly, Pearson’s correlation test showed that there was significant negative correlation between mite abundance and the water physio-chemical parameters salinity (r = -0.574, p = 0.032), electrical conductivity (r = -0.536, p = 0.048), total dissolved solids (r = -0.534, p = 0.049), total hardness (r = -0.621, p = 0.018), and chloride concentration (r = -0.545, p = 0.036), indicating sensitivity of water mites to pollution.

Mites Associated with the European Spruce Bark Beetle Ips typographus (Linnaeus, 1758) in Europe, with New Evidence for the Fauna of Serbia

Various biotic and abiotic factors are the cause of the decline of coniferous forests throughout Europe. Trees weakened by unfavorable weather conditions create an ideal environment for a possible outbreak of bark beetles. The damage caused by bark beetles costs billions of dollars worldwide every year. Extreme climate events are responsible for the enormous forest losses in Tara National Park in the last ten years, leading to a massive bark beetle infestation. The understanding of the diversity and role of mites as biological control agents is still insufficient. In this study, we summarize the current knowledge on the diversity of mites associated with Ips typographus L. in Europe and provide information on the diversity of these mites in Serbia. Paraleius leontonychus, Uroobovella ipidis, Dendrolaelaps quadrisetus, Histiostoma piceae, and Trichouropoda polytricha were detected for the first time in Serbia. Moreover, the occurrence of Paraleius leontonychus represents the southernmost occurrence of this species.

Neglected symbionts and other metazoan invertebrates associated with molluscs from Africa's largest lake: Diversity, biotic interactions and bioindication

Abstract Freshwater molluscs are hosts for diverse metazoan symbionts. However, apart from the digenean helminths, symbionts of molluscs are underreported worldwide. Therefore, this study focused on the diversity of oligochaetes, leeches, mites, insect larvae and nematodes associated with gastropods and bivalves from Lake Victoria, East Africa. Overall, 1,633 mollusc specimens representing 14 species were sampled from the Kenyan part of the lake. Each host specimen was examined to determine co‐occurrence of symbionts (including digeneans) and other metazoan invertebrates, and their microhabitat preferences on/in the hosts. In addition, prevalence and abundance of symbionts were compared for molluscs obtained from an unpolluted site, and sites that are eutrophic and polluted with heavy metals. In total, 33 species were recovered from the molluscs: six oligochaetes, four insects, two mites, two nematodes, one leech and 18 digeneans. The nematode Daubaylia potomaca, mite Unionicola macani, leech Batracobdelloides sp., oligochaetes Chaetogaster limnaei, Dero digitata, Aulophorus africanus, Allonais paraguayensis and Ophidonais serpentina, and gorgoderid digenean larvae are new records for Lake Victoria. Moreover, the genus Bratislavia (Oligochaeta) is reported for the first time in Africa. Our results show that parasitic mites and leeches were absent from mollusc specimens that harboured chironomids. Likewise, there was no co‐occurrence of C. limnaei, D. potomaca and digeneans, suggesting that antagonistic interactions occur between the symbionts. Although co‐occurrence of mites and digeneans in individual mollusc hosts was common, the symbionts occupied different microhabitats. This study shows that prevalence and intensities of U. macani and C. limnaei, were significantly higher in hosts from the unpolluted site, compared with the polluted sites. What is more, D. potomaca and trichopteran larvae, were recorded only from the unpolluted site. The distribution of the chironomid Kiefferulus chloronatus suggests their preference for sites that are rich in organic matter and their ability to tolerate pollution. Information on antagonistic interactions between symbionts might be applicable in biocontrol, especially of digenean species that have veterinary or medical importance. Finally, this study shows a potential for the use of U. macani, C. limnaei, D. potomaca and insect larvae as discriminators of the quality of aquatic habitats.

Functional ecosystem parameters: Soil respiration and diversity of mite (Acari, Mesostigmata) communities after disturbance in a Late Cambrian bedrock environment

AbstractWe analyzed the changes in ecosystem functions (soil respiration and Mesostigmata mite abundance, species richness and diversity) on various habitats after flooding by highly mineralized and acidic drainage water with fine As‐rich pyrite sediments, on a fragment of a natural ecosystem. In total, 177 plots that represented six types of habitats (undisturbed: pine mixed forests, Salix spp. thickets, Juncus effusus communities, wet meadows, and disturbed: bare ground and dead Salix spp. thickets) were sampled twice, in June 2019 and September 2020. Our study revealed that flooding affected essential ecosystem parameters, such as soil Mesostigmata mite abundance, species richness and diversity, and soil respiration, via an extreme decrease of soil pH. In total, 968 mites were collected from pooled data from the two samplings. Mite abundance, species richness and diversity were mainly shaped by habitat type and soil pH, and partially by soil respiration. These parameters were lower in disturbed habitats (bare ground and dead Salix spp. thickets) as compared with undisturbed ones. The highest mean mite density was recorded from mixed forests (4750 ± 600 ind. m−2) and wet meadows (2678 ± 361 ind. m−2), whereas the lowest in bare ground (449 ± 113 ind. m−2) and dead Salix spp. thickets (537 ± 146 ind. m−2). We noticed that mite diversity may be helpful to predict future changes in the physicochemical parameters of soils in disturbed areas. The vegetation patches built up by species adapted to grow in habitats characterized by relatively high metal and metalloid content (J. effusus and Salix spp.) represent an intermediate state of function of ecosystems in the study area.

Habitat and Season Drive Chigger Mite Diversity and Abundance on Small Mammals in Peninsular Malaysia.

Chigger mites are vectors of the bacterial disease scrub typhus, caused by Orientia spp. The bacterium is vertically transmitted in the vector and horizontally transmitted to terrestrial vertebrates (primarily wild small mammals), with humans as incidental hosts. Previous studies have shown that the size of the chigger populations is correlated with the density of small mammals in scrub typhus-endemic regions. Here, we explore interactions between the small mammals and chiggers in two oil palm plantations located in the Perak and Johor states of Peninsular Malaysia. The location in Perak also contained an aboriginal (Orang Asli) settlement. A ~5% sub-sample from 40,736 chigger specimens was identified from five species of small mammals (n = 217), revealing 14 chigger species, including two new records for Malaysia. The abundance and species richness of chiggers were significantly affected by habitat type (highest in forest border), state (highest in Perak), and season (highest in dry). The overall prevalence of Orientia tsutsugamushi DNA in small-mammal tissues was 11.7% and was not significantly affected by host or habitat characteristics, but in Johor, was positively associated with infestation by Leptotrombidium arenicola. These findings highlight the risk of contracting scrub typhus in oil palm plantations and associated human settlements.

Annotated checklist of chigger mites (Trombidiformes: Leeuwenhoekiidae, Trombiculidae and Walchiidae) in Sri Lanka.

Chigger mites (Leeuwenhoekiidae, Trombiculidae, and Walchiidae) are parasites of any terrestrial vertebrate. The present study updates the list of chigger mite (Trombiculidae, Leeuwenhoekiidae, and Walchiidae) species recorded from Sri Lanka along with taxonomic classification based on previous investigations since 1946 to date and our observations in western and southern parts of the country. This checklist listed 15 species in 9 genera within the three chigger families. For now, murid species were the host most sampledparasitized by chiggers in Sri Lanka. However, further studies are required to increase the diversity of chigger mites in Sri Lanka and probably the description of new species, which will be possible with morphological and molecular characterization.