Microbial Communities of Stored Product Mites: Variation by Species and Population.

Arthropod-associated microorganisms are important because they affect host fitness, protect hosts from pathogens, and influence the host's ability to vector pathogens. Stored product mites (Astigmata) often establish large populations in various types of food items, damaging the food by direct feeding and introducing contaminants, including their own bodies, allergen-containing feces, and associated microorganisms. Here we access the microbial structure and abundance in rearing diets, eggs, feces fraction, and mite bodies of 16 mite populations belonging to three species (Carpoglyphus lactis, Acarus siro, and Tyrophagus putrescentiae) using quantitative PCR and 16S ribosomal RNA (rRNA) gene amplicon sequencing. The mite microbiomes had a complex structure dominated by the following bacterial taxa (OTUs): (a) intracellular symbionts of the genera Cardinium and Wolbachia in the mite bodies and eggs; (b) putative gut symbionts of the genera Solitalea, Bartonella, and Sodalis abundant in mite bodies and also present in mite feces; (c) feces-associated or environmental bacteria of the genera Bacillus, Staphylococcus, and Kocuria in the diet, mite bodies, and feces. Interestingly and counterintuitively, the differences between microbial communities in various conspecific mite populations were higher than those between different mite species. To explain some of these differences, we hypothesize that the intracellular bacterial symbionts can affect microbiome composition in mite bodies, causing differences between microbial profiles. Microbial profiles differed between various sample types, such as mite eggs, bodies, and the environment (spent growth medium-SPGM). Low bacterial abundances in eggs may result in stochastic effects in parent-offspring microbial transmission, except for the intracellular symbionts. Bacteria in the rearing diet had little effect on the microbial community structure in SPGM and mite bodies. Mite fitness was positively correlated with bacterial abundance in SPGM and negatively correlated with bacterial abundances in mite bodies. Our study demonstrates critical host-microbe interactions, affecting all stages of mite growth and leading to alteration of the environmental microbiome. Correlational evidence based on absolute quantitation of bacterial 16S rRNA gene copies suggests that mite-associated microorganisms are critical for modulating important pest properties of mites by altering population growth.

Juvenile diet quality and intensity of sexual conflict in the mite Sancassania berlesei.

BACKGROUND: Differing evolutionary interests of males and females may result in sexual conflict, whereby traits or behaviours that are beneficial for male reproductive success (e.g., traits related to male-male competition) are costly for females. Since sexual conflict may play an important role in areas such as speciation, population persistence or evolution of life history traits, understanding what factors modulate the intensity of sexual conflict is important. This study aims to examine juvenile diet quality as one of the underestimated ecological factors that may affect the intensity of sexual conflict via individual conditions. I used food manipulation during the development of the mite Sancassania berlesei to investigate the effects on male reproductive behaviour and competitiveness, male-induced harm to female fitness and female resistance to this harm. RESULTS: Males that were exposed to low-quality food started mating later than the control males, and number of their mating attempts were lower compared to those of control males. Moreover, males from the low-quality diet treatment sired fewer offspring under competition than males from the control treatment. However, the fitness of females exposed to males reared on a poor diet did not differ from that of females mated with control males. Furthermore, female diet quality did not alter their resistance to male-induced harm. CONCLUSION: Overall, diet quality manipulation affected male reproductive behaviour and mating success. However, I found no evidence that the intensity of sexual conflict in S. berlesei depends on male or female conditions. Investigating a broader range of environmental factors will provide a better understanding of sexual conflict dynamics and its feedback into associated evolutionary mechanisms.

[Study on community of acaroid mites breeding in home storages in Linquan Area, Anhui Province].

OBJECTIVE: To investigate the species and diversity of acaroid mites community in home storages in Linquan area, Anhui Province. METHODS: The samples of 48 kinds of storages from the residents in Linquan County were collected, and the mites in them were separated in a microscope directly. RESULTS: Totally 19 species of acaroid mites belonging to 14 genera of 6 families were obtained from the 48 kinds of samples. The diversity analysis showed that the number of species, the species richness index and species diversity index of mites in the habitats were in the order of the other storages > drysaltery > grains. CONCLUSIONS: The quantities of breeding acaroid mites in storages in Linquan area are much larger, meanwhile the species are also very rich, thus in order to reduce the harm of acaroid mites, we should take active measures to control their breeding.

Skin mites in mice (Mus musculus): high prevalence of Myobia sp. (Acari, Arachnida) in Robertsonian mice.

Myobia sp. and Demodex sp. are two skin mites that infest mice, particularly immunodeficient or transgenic lab mice. In the present study, wild house mice from five localities from the Barcelona Roberstonian system were analysed in order to detect skin mites and compare their prevalence between standard (2n = 40) and Robertsonian mice (2n > 40). We found and identified skin mites through real-time qPCR by comparing sequences from the mitochondrial 16S rRNA and the nuclear 18S rRNA genes since no sequences are available so far using the mitochondrial gene. Fourteen positive samples were identified as Myobia musculi except for a deletion of 296 bp out to 465 bp sequenced, and one sample was identified as Demodex canis. Sampling one body site, the mite prevalence in standard and Robertsonian mice was 0 and 26%, respectively. The malfunction of the immune system elicits an overgrowth of skin mites and consequently leads to diseases such as canine demodicosis in dogs or rosacea in humans. In immunosuppressed mice, the probability of developing demodicosis is higher than in healthy mice. Since six murine toll-like receptors (TLRs) are located in four chromosomes affected by Robertsonian fusions, we cannot dismiss that differences in mite prevalence could be the consequence of the interruption of TLR function. Although ecological and/or morphological factors cannot be disregarded to explain differences in mite prevalence, the detection of translocation breakpoints in TLR genes or the analysis of TLR gene expression are needed to elucidate how Robertsonian fusions affect the immune system in mice.

Investigating species boundaries using DNA and morphology in the mite Tyrophagus curvipenis (Acari: Acaridae), an emerging invasive pest, with a molecular phylogeny of the genus Tyrophagus.

Mites of the genus Tyrophagus (Acari: Acaridae) are among the most widespread and common mites, inhabiting diverse natural and anthropogenic habitats. Some species are pests of agricultural products and stored food and/or live in house dust, causing allergies to humans. We sequenced 1.2 kb of the mitochondrial COI gene for 38 individuals belonging to seven species of Tyrophagus, including T. curvipenis, T. putrescentiae, T. fanetzhangorum, T. longior, T. perniciosus, and T. cf. similis. Molecular phylogenetic analyses (1) recovered two major clades corresponding to the presence or absence of eyespots, and (2) separated all included morphological species. Tyrophagus curvipenis and T. putrescentiae had the lowest between-species genetic distances (range, mean ± SD): 14.20-16.30, 15.17 ± 0.40 (K2P). The highest within-species variation was found in T. putrescentiae 0.00-4.33, 1.78 ± 1.44 (K2P). In this species, we recovered two distinct groups; however, no geographical or ecological dissimilarities were observed between them. Based on our analyses, we document important morphological differences between T. curvipenis and T. putrescentiae. For the first time, we record the occurrence of T. curvipenis in the New World and suggest that it may be an emerging pest as it is currently spreading in agricultural produce.

A new species of Thyreophagus (Acari: Acaridae) from Brazil, with notes on species associated with stored food and human habitats and a key to species of this genus.

A new species Thyreophagus cracentiseta n. sp. is described morphologically based on adult females, adult homeomorphic and heteromorphic males collected from chicken feed in Brazil. The Thyreophagus species associated with stored food and human habitats are reviewed, and a key to separate species of this genus is provided.

[Investigation of Lardoglyphus konoi (Astigmata) breeding in stored Solenognathus].

OBJECTIVE: To investigate the mites breeding in stored Solenognathus. METHODS: Solenognathus was collected from a Chinese medicine shop in Wuhu City, and mites were isolated and identified under a microscope. RESULTS: Totally 256 mites were isolated from 500 g Solenognathus, and four species were found, including 219 Lardoglyphus konoi, 12 Tyrophagus longior, 21 Tyrophagus putrescentiae and 4 Euroglyphus maynei. The breeding density of L. konoi was 0.438/g. CONCLUSIONS: There are mites breeding in the stored Solenognathus, and the most mites are L. konoi. Effective measures should be taken to prevent and control it.

Acarine Hypopi (Sarcoptiformes: Acaridae) on Ixodes scapularis (Ixodida: Ixodidae) in Central North America.

Phoretic deutonymphs (hypopi) of Schwiebea sp. mites were detected during examinations of questing adult and nymphal blacklegged ticks, Ixodes scapularis Say, from vegetation at two woodland sites in northeastern Wisconsin, USA, during May and June, 2014. Collection sites were in Marinette and Oconto Counties, respectively. These hypopi are evidently the first reported from ticks in the Western Hemisphere, and they seem to be most similar morphologically to the putatively Holarctic species Schwiebea nova (Oudemans).

The Crotonia fauna of New Zealand revisited (Acari: Oribatida): taxonomy, phylogeny, ecological distribution and biogeography.

New Zealand contains 13 of the 69 species of Crotonia described globally and is the only place where all three genera of the Crotoniinae-Crotonia, Austronothrus and Holonothrus-have been recorded. Due to the pioneering work of Hammer (1966) and Luxton (1982) it also has the highest number of distribution records of Crotonia spp. anywhere. In the present study I build upon previous work to re-examine the Crotonia fauna of New Zealand in the light of recent taxonomic and biogeographical research. A new species is described, C. ramsayi sp. nov., a member of the Unguifera species group, and supplementary descriptions are provided for C. brachyrostrum (Hammer 1966), C. caudalis (Hammer, 1966), C. cophinaria (Michael, 1908), and C. unguifera (Michael 1908), as well as a key to species. Crotonia spp. from New Zealand occur predominantly in localities with relatively low mean annual temperature and high water balance, reflecting a requirement for cool, moist conditions. In New Zealand Crotonia spp. occur in an extremely wide variety of vegetation communities compared with other regions in its range (Australia, Africa and South America), and this is indicative that water balance requirements are met, regardless of vegetation type. Some elements of the New Zealand Crotonia fauna, notably the Cophinaria species group, are common to Australia, Africa and South America, indicating a shared evolutionary history pre-dating the separation of Africa from Gondwana 110 mya. The high proportion of species that occur west of the Alpine Fault is consistent with a relictual distribution of Gondwanan elements on the Australian Plate. However, it is unclear whether uplift of the Southern Alps formed a barrier to dispersal. A high representation of the morphologically closely-related Obtecta, Flagellata and Unguifera groups, shared only with South America (and, for Unguifera, with Oceania) represents a dramatically different faunal composition compared with other former Gondwanan landmasses and is consistent with submergence of most of New Zealand during the Oligocene (ca. 25 mya). All of these characteristics indicate a distinctive evolutionary pathway for the Crotonia fauna since New Zealand separated from the rest of Gondwana 80 mya.

[Investigation of Acaroid mites breeding in stored dry fruits].

OBJECTIVE: To study the species and density of Acaroid mites breeding in stored dry fruits. METHODS: The samples from the dried fruit stores and warehouses were collected, and the mites breeding in them were separated, then the slides with mites were prepared and observed by a light microscope for species identification and counting. The indexes such as the breeding density, species richness index, diversity index and evenness index were calculated. RESULTS: Totally 12 species of Acaroid mites belonging to 6 families and 10 genera were obtained from the total 49 samples. The dominant mite species were Carpoglyphus lactis, Tyrophagus putrescentiae, Acarus siro, and Caloglyphus berlesei. The breeding densities of mites in longans, filberts and plum candies were 79.78, 48.91, 35.73 mites/g, respectively, which were higher than those in other dry fruits. The seasonal variation experiment of mites found that the average breeding density of acaroid mites was higher in July and October, the richness index and diversity index reached the highest value in July, and the evenness index was higher in January and April. The observation of the growth and decline of Acaroid mites under the artificial condition found the number of Caloglyphus berlesei declined sharply and Tyrophagus putrescentiae first increased and then decreased. CONCLUSION: The pollution of Acaroid mites is serious in the stored dried fruits, for which the positive prevention and control measures to the mite breeding should be taken to reduce the harm.

Simultaneous oral mite anaphylaxis (Pancake syndrome) in a father and daughter and a review of the literature

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Molecular identification of house dust mites and storage mites.

Mites are known causes of allergic diseases. Currently, identification of mites based on morphology is difficult if only one mite is isolated from a (dust) sample, or when only one gender is found, or when the specimen is not intact especially with the loss of the legs. The purpose of this study was to use polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the ITS2 gene, to complement the morphological data for the identification of mites to the species level. For this, six species were cultured: Dermatophagoides pteronyssinus, D. farinae, Blomia tropicalis, Tyrophagus putrescentiae, Aleuroglyphus ovatus and Glycycometus malaysiensis. Genomic DNA of the mites was extracted, quantified, amplified and digested individually with restriction enzymes. Hinf I and Ple I differentiated the restriction patterns of D. pteronyssinus and D. farinae. Bfa I and Alu I enzymes differentiated B. tropicalis and G. malaysiensis. Ple I enzyme was useful for the differentiation between T. putrescentiae and A. ovatus. Bfa I was useful for the differentiation of G. malaysiensis from the rest of the species. In conclusion, different species of mites can be differentiated using PCR-RFLP of ITS2 region. With the established PCR-RFLP method in this study, identification of these mites to the species level is possible even if complete and intact adult specimens of both sexes are not available. As no study to date has reported PCR-RFLP method for the identification of domestic mites, the established method should be validated for the identification of other species of mites that were not included in this study.

The importance of starch and sucrose digestion in nutritive biology of synanthropic acaridid mites: alpha-amylases and alpha-glucosidases are suitable targets for inhibitor-based strategies of mite control.

The adaptation of nine species of mites that infest stored products for starch utilization was tested by (1) enzymatic analysis using feces and whole mite extracts, (2) biotests, and (3) inhibition experiments. Acarus siro, Aleuroglyphus ovatus, and Tyroborus lini were associated with the starch-type substrates and maltose, with higher enzymatic activities observed in whole mite extracts. Lepidoglyphus destructor was associated with the same substrates but had higher activities in feces. Dermatophagoides farinae, Chortoglyphus arcuatus, and Caloglyphus redickorzevi were associated with sucrose. Tyrophagus putrescentiae and Carpoglyphus lactis had low or intermediate enzymatic activity on the tested substrates. Biotests on starch additive diets showed accelerated growth of species associated with the starch-type substrates. The inhibitor acarbose suppressed starch hydrolysis and growth of the mites. We suggest that the species with higher starch hydrolytic activity in feces were more tolerant to acarbose, and alpha-amylase and alpha-glucosidase of synanthropic mites are suitable targets for inhibitor-based strategies of mite control.

Morphological diagnosis of the eggs of stored-products mites.

Eggs of 13 species of common, economically important stored-product pest mites (Acarus siro, A. gracilis, Tyrophagus putrescentiae, T. brevicrinatus, Tyroborus lini, Aleuroglyphus ovatus, Caloglyphus redikorzevi, C. oudemansi, Lepidoglyphus destructor, Glycyphagus domesticus, Aeroglyphus robustus, Chortoglyphus arcuatus and Carpoglyphus lactis) from four families (Acaridae, Glycyphagidae, Chortoglyphidae, Carpoglyphidae) were studied in order to build a diagnostic key. The morphological study dealt with shape, size and surface sculpturing of eggs. Morphological details were visualised using scanning electron microscopy. A key for distinguishing eggs at genus and species level was developed for the major stored-product mites.

Mites associated with stored products in Greece.

A faunistic survey of mites was conducted in many product stores during a 6-year study period, 2000-2005, in Greece. A total of 1,073 samples were taken from 34 Greek counties. The survey was carried out on grains (wheat, maize, oat, barley), flour, bran, manufactured agricultural foodstuffs, dried fruits (figs, raisins), residues and dust, stored in varying quantities in five types of storage facilities (stores of agricultural cooperative unions, farm stores, commercial stores, flour mills and silos). Dominance-frequency analysis and redundancy analysis (RDA) were used to reveal the preferences of the collected taxa. Approximately 55% of the samples contained mites and 65 mite taxa were identified, belonging to 15 families in four orders. Six species, namely, Acarus gracilis Hughes, A. immobilis Griffiths, Caloglyphus oudemansi (Zachvatkin), Suidasia medanensis Oudemans, Tyrophagus perniciosus Zachvatkin and Kleemania plumigera (Oudemans), were new to the fauna of Greece. Five species, Tyrophagus similis Volgin, Blattisocius mali (Oudemans), Neoseiulus barkeri (Hughes), Cheyletus cacahuamilpensis Baker and Storchia robustus (Berlese), were recorded for the first time in stored products in Greece. Lepidoglyphus destructor (Schrank), Tyrophagus putrescentiae (Schrank) and Acarus siro L. were dominant or intermediate in all storage facilities examined. Cheyletus malaccensis Oudemans was the most common predatory mite. The highest percentage of infestation (65.3) was recorded in the samples from stores of agricultural cooperative unions. Residue-type materials had the highest degrees and percentages of infestation.

Comparison of communities of stored product mites in grain mass and grain residues in the Czech Republic.

In storage facilities one can find grain either in stored grain mass or in grain residues in the store corners or machinery. Although it is claimed that grain residues are serious pest reservoirs since they harbor numbers of stored product arthropods and are connected via continuous emigration with grain mass, the documentation for this is not convincing. Therefore in 78 selected grain stores, we simultaneously sampled the grain mass and residues in order to compare concurrent mite communities in these two different habitats. We found 30 species in about 614,000 individuals in residues and 23 species in about 20 000 individuals in grain mass. Canonical correspondence analysis (CCA) of transformed abundance data showed differences in the communities of mites in grain mass and residues: (i) species associated to grain residues (e.g. Tyrophagus longior, Tydeus interruptus, Acarus farris and Cheyletus eruditus) and (ii) species associated to both grain mass and grain residues (e.g. Tarsonemus granarius, Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus destructor and Cheyletus malaccensis). Although the residue samples had more mites and higher species diversity than the stored grain mass, no correlation in mite abundance and species numbers between samples from grain residues and grain mass was found, thereby indicating low connectivity of these two habitats.

Exposure of workers to mites in Finnish groceries.

We assessed the mite exposure of workers in Finnish groceries by collecting samples of settled dust in 5 different grocerys. Mites were counted and identified microscopically. Mite allergen (Der p 1 and Der f 1) content of dust was analyzed with 2-site ELISA. Mites were found in 20-100 % of the samples, both from storage and salesrooms. Seven samples (8 %) contained more than 100 mites per gram dust and 3 additional samples (6 %) more than 500 mites per gram dust, the suggested limits for mite sensitization and acute allergic symptoms, respectively. Most of the mites were storage mites belonging to Astigmata (Acaridae, Glycyphagidae) or Prostigmata (tarsonemids). House dust mites were found only occasionally. One dust sample out of 15 contained Der p 1, and none contained Der f 1.

Molecular identification of pathogenic house dust mites using 12S rRNA sequences.

House dust mites are microarthropods implicated in the cause of allergic diseases. Currently, there is no phylogenetic analysis of dust mites based on genomic or mitochondrial DNA (mtDNA) evidence. For the first time, we report evolutionary relationships based on partial mtDNA 12S rRNA sequences among the four dust mite families Pyroglyphidae (Dermatophagoides pteronyssinus), Glycyphagoidea (Glycyphagus privatus), Acaridae (Aleuroglyphus ovatus), and Echimyopodidae (Blomia tropicalis). Thirteen sequence variants were obtained and phylogenetic analysis showed two monophyletic clades composed of two species each. Contrary to current taxonomic classification, the Acaridae clustered in a monophyletic group with the Pyroglyphidae. Considering the current difficulties in identifying these medically important species for the purpose of eradication and treatment, it is significant that sequence data are capable of discriminating between species belonging to different families of dust mites.

[Composition and diversity of acaroid mite community in different environments in Huainan City].

OBJECTIVE: To investigate the composition and diversity of acaroid mite community in Huainan City. METHODS: Dust samples were collected from storage circumstances, human dwellings and working places. Acaroid mites were isolated, counted and identified. 30 sampling spots from each of the three environments were selected, and 2 samples, each with 10 g, were collected from each sampling spot. RESULTS: 26 species of acarid mites were identified from the three environments. These acarid mites belonged to 19 genera, 7 families. Diversity analysis showed that the average breeding density ranged from 15.35 +/- 6.13 to 31.27 +/- 8.34, the number of species ranged from 11 to 14, the values of the species richness index Rmargalef for the three circumstances raged from 1.99 to 4.35, the species diversity index (Shannon-Wiener index) ranged from 2.27 to 3.13, and Pielou index ranged from 0.95 to 0.96. CONCLUSION: The composition and diversity of acaroid mite community in three different circumstances are different significantly, which might be relevant to temperature, humidity and human interference.

Phylogenetic relationships in rhinonyssid mites (Acari: Rhinonyssidae) based on ribosomal DNA sequences: insights for the discrimination of closely related species.

The complete internal transcribed spacer 1 (ITS1), 5.8S rDNA and ITS2 region of the ribosomal DNA from 11 species of rhinonyssid mites ( Tinaminyssus columbae, T. minisetosum, T. sartbaevi, T. bubulci, T. melloi, T. streptopelioides, Sternostoma fulicae, S. boydi, S. strandtmanni, S. turdi, Rhinonyssus tringae) were sequenced to assess the utility of this genomic region in resolving taxonomic questions in this group and to estimate phylogenetic relationships between species. Two different geographic locations of T. melloi and T. streptopelioides were analyzed to detect intraspecies variation. Our study shows that ribosomal sequences can help to discriminate between T. melloi and T. sartbaevi, which are morphologically very close and difficult to separate by classic methods. The resulting phylogenetic tree shows some differences from the current taxonomy of the family Rhinonyssidae. This study appeals for the revision of the taxonomic status of S. boydi and closely related species which parasitize aquatic birds and suggests the synonymy of S. boydi and S. strandtmanni, despite the different hosts of the two mites.