Stored Product Mites Research Articles

Bio-efficacy of some plant extracts as a new acaricide for control of the house dust and stored product mites

ABSTRACT House mites frequently trigger allergic conditions. Although conventional treatments are effective, they can result in drug resistance and pose risks to the environment, human health, and non-target organisms. Therefore, this study evaluates new botanical extracts for their biological activities against Dermatophagoides pteronyssinus (Trouessart 1897; Pyroglyphidae), D. farinae (Hughes 1961; Pyroglyphidae), and Tyrophagus putrescentiae (Schrank 1781; Acaridae), not only to control them but also to reduce their allergens (dead bodies and faecal particles) by keeping them away. It is noteworthy that of these plants, Allium cepa L. (Alliaceae) and Solanum melongena L. (Solanaceae) peel extracts, as well as leaves of Hibiscus sabdariffa L. (Malvaceae), were tested for the first time in the present study as new bioacaricides, while Piper nigrum L. (Piperaceae) and H. sabdariffa leaves proved to be new botanical repellents for these mite species. Based on LC50 values, A. cepa, Beta vulgaris, and S. melongena extracts had the most potent toxic effects on these mite species, while extracts of Aloe vera, Capsicum annum, and P. nigrum had the strongest repellent activity against them at the highest concentration. These natural plant extracts may have valuable potential as new acaricidal products.

A novel Bartonella-like bacterium forms an interdependent mutualistic symbiosis with its host, the stored-product mite Tyrophagus putrescentiae.

A novel Bartonella-like symbiont (BLS) of Tyrophagus putrescentiae was characterized. BLS formed a separate cluster from the Bartonella clade together with an ant symbiont. BLS was present in mite bodies (103 16S DNA copies/mite) and feces but was absent in eggs. This indicated the presence of the BLS in mite guts. The BLS showed a reduction in genome size (1.6 Mb) and indicates gene loss compared to Bartonella apis. The BLS can be interacted with its host by using host metabolic pathways (e.g., the histidine and arginine metabolic pathways) as well as by providing its own metabolic pathways (pantothenate and lipoic acid) to the host, suggesting the existence of a mutualistic association. Our experimental data further confirmed these potential mutualistic nutritional associations, as cultures of T. putrescentiae with low BLS abundance showed the strongest response after the addition of vitamins. Despite developing an arguably tight dependency on its host, the BLS has probably retained flagellar mobility, as evidenced by the 32 proteins enriched in KEGG pathways associated with flagellar assembly or chemotaxis (e.g., fliC, flgE, and flgK, as highly expressed genes). Some of these proteins probably also facilitate adhesion to host gut cells. The microcin C transporter was identified in the BLS, suggesting that microcin C may be used in competition with other gut bacteria. The 16S DNA sequence comparison indicated a mite clade of BLSs with a broad host range, including house dust and stored-product mites. Our phylogenomic analyses identified a unique lineage of arachnid specific BLSs in mites and scorpions.IMPORTANCEA Bartonella-like symbiont was found in an astigmatid mite of allergenic importance. We assembled the genome of the bacterium from metagenomes of different stored-product mite (T. putrescentiae) cultures. The bacterium provides pantothenate and lipoic acid to the mite host. The vitamin supply explains the changes in the relative abundance of BLSs in T. putrescentiae as the microbiome response to nutritional or pesticide stress, as observed previously. The phylogenomic analyses of available 16S DNA sequences originating from mite, scorpion, and insect samples identified a unique lineage of arachnid specific forming large Bartonella clade. BLSs associated with mites and a scorpion. The Bartonella clade included the previously described Ca. Tokpelaia symbionts of ants.

Acaricidal activities of paeonol from Moutan Cortex, dried bark of Paeonia × suffruticosa, against the grain pest mite Aleuroglyphus ovatus (Acari: Acaridae).

Aleuroglyphus ovatus (Acari: Acaridae) is a major pest mite of stored grains that is distributed worldwide. Paeonol, a phenolic component of the essential oil extracted from the Chinese herb Paeonia moutan, possesses a range of biological activities, including antiviral, antifungal and acaricidal activity. This study investigated the bioactivity of paeonol against A. ovatus and its effect on the activity of detoxification enzymes. The bioactivity of paeonol against A. ovatus was determined by contact, fumigation and repellency bioassays, and the mechanism was preliminarily explored via morphological observation of the color changes of mite epidermis and determination of the changing trend of some important enzymes associated with acaricidal efficacy in the mites. The results showed that the median lethal concentration (LC50) in the contact and fumigation bioassays was 9.832μg/cm2 and 14.827μg/cm3, respectively, and the acaricidal activity of paeonol was higher under direct contact than under fumigation. Dynamic symptomatology studies registered typical neurotoxicity symptoms including excitation, convulsion and paralysis in A. ovatus treated with paeonol. The enzyme activity of catalase (CAT), nitric oxide synthase (NOS) and glutathione-S-transferase (GST) was higher, whereas the activity of superoxide dismutase (SOD) and acetylcholinesterase (AChE) was lower, compared to the control group. CAT, NOS and GST were activated, whereas SOD and AChE activities were inhibited after paeonol intervention. Our findings suggest paeonol has potent acaricidal activity against A. ovatus and thus may be used as an agent to control the stored-product mite A. ovatus.

Effect of Microwave Energy on Some Stored Product Mites

Effect of Microwave Energy on Some Stored Product Mites

The Effect of Residual Pesticide Application on Microbiomes of the Storage Mite Tyrophagus putrescentiae.

Arthropods can host well-developed microbial communities, and such microbes can degrade pesticides and confer tolerance to most types of pests. Two cultures of the stored-product mite Tyrophagus putrescentiae, one with a symbiotic microbiome containing Wolbachia and the other without Wolbachia, were compared on pesticide residue (organophosphate: pirimiphos-methyl and pyrethroid: deltamethrin, deltamethrin + piperonyl butoxide)-containing diets. The microbiomes from mite bodies, mite feces and debris from the spent mite diet were analyzed using barcode sequencing. Pesticide tolerance was different among mite cultures and organophosphate and pyrethroid pesticides. The pesticide residues influenced the microbiome composition in both cultures but without any remarkable trend for mite cultures with and without Wolbachia. The most influenced bacterial taxa were Bartonella-like and Bacillus for both cultures and Wolbachia for the culture containing this symbiont. However, there was no direct evidence of any effect of Wolbachia on pesticide tolerance. The high pesticide concentration residues in diets reduced Wolbachia, Bartonella-like and Bacillus in mites of the symbiotic culture. This effect was low for Bartonella-like and Bacillus in the asymbiotic microbiome culture. The results showed that the microbiomes of mites are affected by pesticide residues in the diets, but the effect is not systemic. No actual detoxification effect by the microbiome was observed for the tested pesticides.

The Negative Effects of Feces-Associated Microorganisms on the Fitness of the Stored Product Mite Tyrophagus putrescentiae.

Feces have been suggested as a major source of microorganisms for recolonization of the gut of stored product mites via coprophagy. The mites can host microorganisms that decrease their fitness, but their transmission is not known. To address the role of fecal microbiota on mite fitness, we performed an experimental study in which the surfaces of mite (Tyrophagus putrescentiae) eggs were sterilized. Mites eggs (15 per experimental box) were then hatched and grown on feedstock with and without feces. These experiments were conducted with four distinct T. putrescentiae populations (5L, 5K, 5N, and 5P), and mite population density after 21 day of cultivation was used to assess mite fitness and the impact of fecal microbiota on fitness. Population density was not affected by the presence of feces in two of the cultures (5L and 5K), while significant effects of feces were observed in the other cultures (5N and 5P). Mite culture microbial communities were analyzed using cultivation-independent next-generation amplicon sequencing of microbial 16S and 18S ribosomal RNA (rRNA) genes in the fitness influenced populations (5N and 5P). Several microbial taxa were associated with fecal treatments and reduced mite fitness, including Staphylococcus and Bartonella-like bacteria, and the fungal genera Yamadazyma, Candida, and Aspergillus. Although coprophagy is the transmission route mites used to obtain beneficial gut bacteria such as Bartonella-like organisms, the results of this study demonstrate that fecal-associated microorganisms can have negative effects on some populations of T. putrescentiae fitness, and this may counteract the positive effects of gut symbiont acquisition.

Interactions of the Intracellular Bacterium Cardinium with Its Host, the House Dust Mite Dermatophagoides farinae, Based on Gene Expression Data.

ABSTRACTDermatophagoides farinae is inhabited by an intracellular bacterium, Cardinium. Using correlations between host and symbiont gene expression profiles, we identified several important molecular pathways that potentially regulate/facilitate their interactions. The expression of Cardinium genes collectively explained 95% of the variation in the expression of mite genes assigned to pathways for phagocytosis, apoptosis, the MAPK signaling cascade, endocytosis, the tumor necrosis factor (TNF) pathway, the transforming growth factor beta (TGF-β) pathway, lysozyme, and the Toll/Imd pathway. In addition, expression of mite genes explained 76% of the variability in Cardinium gene expression. In particular, the expression of the Cardinium genes encoding the signaling molecules BamD, LepA, SymE, and VirD4 was either positively or negatively correlated with the expression levels of mite genes involved in endocytosis, phagocytosis, and apoptosis. We also found that Cardinium possesses a complete biosynthetic pathway for lipoic acid and may provide lipoate, but not biotin, to mites. Cardinium gene expression collectively explained 84% of the variation in expression related to several core mite metabolic pathways, and, most notably, a negative correlation was observed between bacterial gene expression and expression of mite genes assigned to the glycolysis and citric acid cycle pathways. Furthermore, we showed that Cardinium gene expression is correlated with expression levels of genes associated with terpenoid backbone biosynthesis. This pathway is important for the synthesis of pheromones, thus providing an opportunity for Cardinium to influence mite reproductive behavior to facilitate transmission of the bacterium. Overall, our study provided correlational gene expression data that can be useful for future research on mite-Cardinium interactions.IMPORTANCE The molecular mechanisms of mite-symbiont interactions and their impacts on human health are largely unknown. Astigmatid mites, such as house dust and stored-product mites, are among the most significant allergen sources worldwide. Although mites themselves are the main allergen sources, recent studies have indicated that mite-associated microbiomes may have implications for allergen production and human health. The major medically important house dust mite, D. farinae, is known to harbor a highly abundant intracellular bacterium belonging to the genus Cardinium. Expression analysis of the mite and symbiont genes can identify key mite molecular pathways that facilitate interactions with this endosymbiont and possibly shed light on how this bacterium affects mite allergen production and physiology in general.

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.

Cardinium and Wolbachia are negatively correlated in the microbiome of various populations of stored product mite Tyrophagus putrescentiae

ABSTRACTThe microbiomes of several populations of Tyrophagus putrescentiae differ in the composition and profiles of intracellular symbiotic bacteria and gut-associated bacteria. We try to describe the interaction among symbiotic bacteria in T. putrescentiae microbiomes. The symbionts profiles were constructed by barcode sequencing of 16S DNA. Several TP populations were analyzed with respect to intracellular symbionts (Wolbachia, Cardinium, Solitalea-like, and Blattabacterium-like) and selected associated bacteria (Bacillus cereus and Bartonella-like) under different diet treatments (diet shifts). The results show two separate co-occurring groups. Wolbachia co-occurs with Blattabacterium, Bartonella, and Solitalea while Cardinium is distinctly separate. The rest of the microbiome including Bacillus cereus have more complex relationships with Wolbachia and Cardinium, suggesting more frequent horizontal transfers. The negative correlation between intracellular symbiotic bacteria Cardinium and Wolbachia is discussed in terms of within-host competition. The profile changes were analyzed to assess the effects of population, diet shifts and their interaction in terms of explained variability. The mite population explained highest variability in all bacterial species. Intracellular symbionts (Wolbachia and Cardinium) and proposed intracellular symbionts (Solitalea and Blattabacterium) show high stability, with variation being influenced mainly by the population. Bacillus cereus and Bartonella bacteria are influenced by diet shift supporting their presence in the gut lumen.

Acaricidal and Chemical Composition of Allium sativum L. Crude Extracts Against Stored Product Mites Suidasia pontifica Oudemans

Natural product calls the attention of the public nowadays, because of its promising control measures which are eco-friendly, safe and yet effective against a wide range of stored product mite pest. Current investigation aims to evaluate the efficacy garlic crude extract (GCE) against Suidasia pontifica, that causes allergenic and possess a great challenge in postharvest agricultural products especially in areas of human activities. Based on the response of S. pontifica the estimated minimum effective concentration (MEC) of garlic crude extracts to give complete kill at different developmental stages was 0.75 - 1.0 g/L concentration. GC/MS analysis revealed various biologically active components of garlic, including oleyl alcohol (41.41 %), γ-sitosterol (16.49 %), 3-vinyl-1 2-dithiacyclohex-4-ene (5.78 %), 2-vinyl-4h-1 3-dithiine (5.52 %), 24-nourse-3,12-diene (4.39 %) and 1-octadecanol methyl ether (4.37 %) and its derivatives. Four out of six major components of the identified compound from GCE were used for industrial application. The other two were still unknown for its uses. The results support the possible use of A. sativum extracts as an alternative to synthetic acaricide.

Morphological and molecular characteristics of stored-product mites found on Brazilian ripened cheeses

The production and consumption of cheese that contains mites has become a gastronomical trend in Brazil. However, the making of these cheeses has been a traditional process, and thereby empirical in nature, without the regulatory oversight of the Brazilian authorities. Depending on the species, these mites might present health risks for those consuming them. Therefore, we conducted initial morphological and molecular analyses to characterize the diversity of cheese mites present on these Brazilian ripened cheeses. Our results revealed that the mites were predominantly Tyrophagus putrescentiae and to a lesser degree Sancassania aff. feytaudi. Future studies need to be performed to indicate whether these species meet the requirements to be characterized as generally recognized as safe (GRAS status) and are capable of conferring unique and desirable sensory characteristics to the cheese.

Acaricidal effect of three zeolite formulations on different life stages of Tyrophagus putrescentiae (Schrank) and Acarus siro L. (Sarcoptiformes: Acaridae)

The mould mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) and the flour mite, Acarus siro L. (Sarcoptiformes: Acaridae) are very common stored-product mites found in a wide spectrum of commodities of both plant and animal origin. In this study, we evaluated three zeolite formulations as stored-wheat protectants regarding the management of larvae, nymphs and adults of T. putrescentiae and A. siro at different exposure intervals, i.e., 1, 2, and 5 days (d), and doses, i.e., 200, 500, and 1000 ppm. We found that the zeolite formulations tested here can be effective for the control of both stored-product mite species. Mortality of all stages of T. putrescentiae and A. siro was considerably affected by dose and exposure intervals, i.e. the higher the dose and the longer the exposure time, the greater the mortality. Nevertheless, 100% mortality was not recorded on any of the life stages and formulations tested, even in the case of the highest dose and the longest exposure interval. All zeolite formulations provided the same efficacy level, which was similar for immature stages and adults of both mite species. The results of the present study suggest that longer exposures of the evaluated zeolite formulations are required to increase the efficacy on the control of T. putrescentiae and A. siro.

Eradication of the Stored-Product Mite, Tyrophagus putrescentiae (Shrank) in Flour and Wheat Bran Using Microwave Energy

Mortality of adults and larvae of the stored product mite, Tyrophagus putrescentiae infested flour or wheat bran exposed to microwave radiation (2450 MHZ) was evaluated as a function of exposure time and power. Mortality experiments were conducted at exposure times 60-300 sec at power level of 110 W and from 10 to 90 sec at 330 and 550 W. Adult and larva mortalities were higher in flour with 12.5% moisture content (m.c.) than in wheat bran with 8.5 % m.c. The minimum average temperature (27.8 oC) was recorded in wheat bran at 330 W for 10 sec, whereas the maximum average was 60.5oC in flour at 550 W for 90 sec. Complete mortality of larvae and adults of T. putrescentiae was obtained at 45 and 46.6 oC, respectively. T. putrescentiae larvae presented a mortality rate higher than adults when exposed to the same Mw energy radiation.

Seasonal abundance and diversity of astigmatic mites in storage facilitiesof Punjab, India

Stored-product mites cause economic loss by feeding on stored grain and imperil the human health by contamination of food by allergens. The present study has been carried out to access the mite fauna associated with warehouses and other grain storage facilities of Punjab. Samples were collected three times a year. The year was divided into three climatic classes i.e. summer CCL I, rainy CCL II and winter CCL III. Mites were found in 146 (83.90%) of 168 analyzed samples. A total of 2400 mites were isolated of which, 1326 (55.25%) mites were found in samples collected during rainy season, 747 (31.12%) during summer and 327 (13.63%) during winter season. A total 2400 mites were isolated of which 1364 (56.83%) mites were from order Astigmata. Among the collected specimens, 11 species of astigmatid mites were identified belonging to 7 genera of 4 families i.e. acaridae, glycyphagidae, pyroglyphidae and saproglyphidae. Tyrophagus putrescentiae (18.3%) was found to be the most abundant mite species followed by Glycyphagus domestics (17.48%).

Laboratory Studies on the Mesostigmatid Mites Androlaelaps aegypticus (Laelapidae) and Proctolaelaps gizanensis (Ascidae) on Three Mite Pests at Different Conditions

This work was conducted to determine the effect of three astigmatid stored product mites (immature stages) Tyrophagus putrescentiae, Rhizoglyphus echinopus (Acaridae) and Lepidoglyphus destructor (Glycyphagidae) as food sources on the biology of the two predatory mites, Androlaelaps aegypticus (Laelapidae)and Proctolaelaps gizanensis(Ascidae). Theincubation period,life cycle, longevity and life span of both females and males and the female fecundity (number of laid eggs) of the two mite individuals weresignificantly differed according to the different experiment conditions. The developmental period of both A. aegypticus and P. gizanensis was faster for the male members than females and the immature stages of L. destructor decreased these periods, than other introduced prey. Also, the duration periods were increased at 20oC than 25 and 30oC. The number of deposited eggs by females of the two tested predatory mites increased when the adult females fed on the immature stages of T. putrescentiae than other preys, and 30oC increased this number than other temperature.

Sensitization to the storage mites Lepidoglyphus destructor and Tyrophagus putrescentiae (Acari, Sarcoptiformes, Astigmatina) in a suburban population in Southern Poland

Mite infestation of stored products is a serious threat to food safety and public health. These stored product mites are not only serious pests of stored food but also cause allergies in humans. Thirty serum samples from patients living in suburban areas of Upper Silesia (South Poland) were tested for sensitization to two species of storage mites: Lepidoglyphus destructor [LD] and Tyrophagus putrescentiae [TP]. Patient antibodies against particular antigens were identified using anti-human anti-IgE monoclonal antibodies. Fifteen protein fractions from LD gave positive reactions with IgE antibodies and 18 from TP. Seven of the 30 samples showed positive reactions to a protein fraction measuring about 29 kDa from LD and six reacted with a fraction measuring about 25 kDa from TP. These findings may imply the existence of many protein fractions with allergenic properties besides the characterized allergens in the two tested species.

Development of Cheyletus malaccensis (Acari: Cheyletidae) feeding on mite species found in commercial poultry systems: Megninia ginglymura (Acari: Analgidae) and Tyrophagus putrescentiae (Acari: Acaridae)

Intensive egg production affects the welfare of confined laying hens, which increases the risk of epidemics. Ectoparasitic hematophagous mites and saprophagous feather mites cause low productivity and decreased egg quality. This study aimed to compare the biology of Cheyletus malaccensis (Oudemans) (Prostigmata: Cheyletidae) feeding on the prey Megninia ginglymura (Mégnin) (Astigmata: Analgidae) and Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) in order to support the potential use of this predator in biological control strategies in the poultry industry. The study started with 30 eggs of C. malaccensis, isolated in experimental units, which developed into their different stages while feeding on the feather mite M. ginglymura and the stored product mite T. putrescentiae at 25±1ºC, 80±5% relative humidity and 12-hour photoperiod. Immature stages were evaluated three times a day and the adult stage once a day. Adult females were unmated. Cheyletus malaccensis feeding on M. ginglymura resulted in a higher fertility rate, with 310.7±45.8 eggs/female, than with T. putrescentiae as prey, with 32.7±4.5 eggs/female. Furthermore, the oviposition period was higher feeding on M. ginglymura, 53.0±6.3 days, than on T. putrescentiae, 12.6±1.9 days. The net reproductive rate (Ro), the innate capacity for increase (rm), the mean generation time (T) and the finite rate of increase (λ) were higher for the generation fed on M. ginglymura. Cheyletus malaccensis is a likely natural enemy of M. ginglymura, and it is able to develop and reproduce while feeding exclusively on it.

Detection and localization of Solitalea-like and Cardinium bacteria in three Acarus siro populations (Astigmata: Acaridae)

Bacteria associated with mites influence their fitness, nutrition and reproduction. Previously, we found Solitalea-like (Sphingobacteriales) and Candidatus Cardinium (Cytophagales) bacteria in the stored product mite Acarus siro L. by cloning and using pyrosequencing. In this study, taxon-specific primers targeting 16S rRNA gene were used to detect and quantify the bacteria in mites and eggs of three A. siro populations. The specific probes for fluorescent in situ hybridization (FISH) were used to localize Solitalea-like and Cardinium bacteria in mite bodies. The population growth as an indirect estimator of fitness was used to describe the mite-bacteria interactions on (1) control diet; (2) rifampicin supplemented diet; (3) tetracycline supplemented diet; (4) rifampicin pretreated mites; (5) tetracycline pretreated mites. Solitalea-like 16S rRNA gene sequences from A. siro formed a separate cluster together with sequences from Tyrophagus putrescentiae. qPCR analysis indicated that number of Solitalea-like bacteria 16S rRNA gene copies was ca. 100× higher than that of Cardinium and the numbers differed between populations. FISH analysis localized Solitalea-like bacteria in the parenchymal tissues, mesodeum and food bolus of larvae, nymphs and adults. Solitalea-like, but not Cardinium bacteria were detected by taxon-specific primers in mites and eggs of all three investigated populations. None of the antibiotic treatments eliminated Solitalea-like bacteria in the A. siro populations tested. Rifampicin pretreatment significantly decreased the population growth. The numbers of Solitalea-like bacteria did not correlate with the population growth as a fitness indicator. This study demonstrated that A. siro can host Solitalea-like bacteria either alone or together with Cardinium. We suggest that Solitalea-like bacteria are shared by vertical transfer in A. siro populations.

Populations of Stored Product Mite Tyrophagus putrescentiae Differ in Their Bacterial Communities.

Background: Tyrophagus putrescentiae colonizes different human-related habitats and feeds on various post-harvest foods. The microbiota acquired by these mites can influence the nutritional plasticity in different populations. We compared the bacterial communities of five populations of T. putrescentiae and one mixed population of T. putrescentiae and T. fanetzhangorum collected from different habitats.Material: The bacterial communities of the six mite populations from different habitats and diets were compared by Sanger sequencing of cloned 16S rRNA obtained from amplification with universal eubacterial primers and using bacterial taxon-specific primers on the samples of adults/juveniles or eggs. Microscopic techniques were used to localize bacteria in food boli and mite bodies. The morphological determination of the mite populations was confirmed by analyses of CO1 and ITS fragment genes.Results: The following symbiotic bacteria were found in compared mite populations: Wolbachia (two populations), Cardinium (five populations), Bartonella-like (five populations), Blattabacterium-like symbiont (three populations), and Solitalea-like (six populations). From 35 identified OTUs97, only Solitalea was identified in all populations. The next most frequent and abundant sequences were Bacillus, Moraxella, Staphylococcus, Kocuria, and Microbacterium. We suggest that some bacterial species may occasionally be ingested with food. The bacteriocytes were observed in some individuals in all mite populations. Bacteria were not visualized in food boli by staining, but bacteria were found by histological means in ovaria of Wolbachia-infested populations.Conclusion: The presence of Blattabacterium-like, Cardinium, Wolbachia, and Solitalea-like in the eggs of T. putrescentiae indicates mother to offspring (vertical) transmission. Results of this study indicate that diet and habitats influence not only the ingested bacteria but also the symbiotic bacteria of T. putrescentiae.

Assessment of Bacterial Communities in Thirteen Species of Laboratory-Cultured Domestic Mites (Acari: Acaridida).

House dust mites (HDMs) and stored-product mites (SPMs) of various species inhabit human homes and stored agricultural products. These mites are carriers and hosts of microorganisms that enable their survival. The bacteriome from 13 species of SPMs and HDMs was analyzed and compared by 454 pyrosequencing of partial 16S rRNA gene amplicons. Altogether 128,052 sequences were obtained and assigned to 71 operational taxonomic units (OTUs) at the 97% identity level. The number of sequences in the OTUs between species of mites ranged from 6 to 31 in the individual mite species. We did not find any significant effect of diet or evolutionary origin of mites or their interaction on the composition of the mite bacteriome. In mite species with low bacterial diversity, the bacterial communities were dominated by potential symbiotic or parasitic bacteria, i.e., Cardinium in Dermatophagoides farinae (Hughes, 1961) and Aeroglyphus robustus (Banks 1906) and the enteric bacteria Erwinia in Blomia tropicalis Van Bronswijk, de Cock & Oshima, 1974 and Xenorhabdus in Tyroborus lini (Oudemans, 1924). Among the bacterial species identified, Staphylococcus, Bacillus, Kocuria, Brevibacterium, Corynebacterium, and Brachybacterium likely serve as food sources for the mites. The domestic acaridid mites carried high numbers of various bacteria that are potential threats to human health. These results contribute to the general understanding of the ecology of mite adaptation to human-made habitats.