The Influence of Indoor Environmental Factors on the Prevalence of House Dust Mites as Aeroallergens in Bandar Abbas Student Dormitories, South of Iran, 2019

This study was conducted to determine the influence of environmental factors on the prevalence of house dust mites in student dormitories of Bandar Abbas city. In this study, 64 dust samples were collected from seven randomly selected dormitories located in various areas of the Bandar Abbas. The collected mites were isolated and mounted in Hoyer’s medium and identified using a morphological key. The associations between the environmental factors and the density of house dust mites were investigated. In total, 1,093 adult mites were collected and identified. They consisted of four species including Dermatophagoides pteronyssinus Trouessart (57.6%), Dermatophagoides farinae Hughes (24.3%) and Dermatophagoides evansi Fain (14.9%) (Acari: Pyroglyphidae), and Cheyletus malaccensis Oudemans (3.2%) (Acari: Cheyletidae). All of the dormitories were contaminated by more than one house dust mites species and the mean density of house dust mites in dormitories was 8.3 ± 0.2 mites/g of dust. There was a significant relationship between average house dust mites density and some of environmental factors such as relative humidity, temperature, floor covering type, and number of occupants (P < 0.05). Results of this study revealed that two major allergenic dust mites, D. pteronyssinus and D. farinae, were the most prevalent and collected from all of dormitories and some of indoor environmental factors found to influence mites’ population.

The first complete mitochondrial genome of Cheyletus malaccensis (Acari: Cheyletidae): gene rearrangement

The predatory mite Cheyletus malaccensis (Acari: Cheyletidae), commonly occurring in stores of various food commodities, is an important natural enemy of stored product pests. Disentangling the mt genome sequence of C. malaccensis at molecular level can decrease uncertainties during morphological identification and is useful in reconstructing the phylogeny of Acariformes group. In this study, the complete mitogenome of C. malaccensis was sequenced by the next-generation sequencing. After assembly and annotation, we found the circular 14,732 bp mitogenome of C. malaccensis, containing 13 protein coding genes, 2 ribosomal RNA (rRNA) genes and 22 transfer RNA (tRNA) genes. Compared with the ancestral mitogenome organization of arthropods, most of tRNA were truncated without D-arm or/and TψC-arm. Rearrangement was found in 12 mitogenome genes. Phylogenetic analyses based on the mitogenome data from other 29 mite species were inferred by Bayesian and maximum likelihood methods, which strongly supported the closer relationship between C. malaccensis and Tetranychidae than other mites. The obtained results represent the first complete mitochondrial genome record for Cheyletidae group. It may help improve molecular phylogenetic relationship and population genetics of the Cheyletidae.

Dominance and Frequency of Mite Species Associated with Poultry Droppings

The present study was carried out onAl-Saqlawiya poultry farm's soil (Anbar, Iraq) for the period of 8 months (November 2018- June 2019). A total of 75 samples of poultry droppings were collectedrandomly. 552 individuals of mite,belonging to 3 orders and 8 families representing 15 species, were found. These species were: Acarus gracilis, Acarus siro, Caloglyphus berlesi, Androlaelaps casalis, Sejus temperaticus, Parasitus paraconsanguineus, Eugamasus butleri, Macrocheles medarius, Macrocheles glaber, Macrocheles muscaedomesticae, Macrocheles matrius, Kleemannia plumosus, Cheyletus eruditus, Cheyletus malaccensis, and Pyemotes herfsi. The highest population density belonged to order Astigmata, followed by orders Mesostigmata and Prostigmata, respectively. The dominance and frequency of mite species were linked to the availability of appropriate conditions in terms of food source and temperatures registered in theIraqi Meteorological Directorate. Thehighest mite population densities were recorded during the winter months compared to the summer months.

Age-Stage, Two-Sex Life Tables of the Predatory Mite Cheyletus Malaccensis Oudemans at Different Temperatures

Cheyletus malaccensis Oudemans is a predatory mite inhabiting grain depots in China. The relationship between temperature and the population growth rate of C. malaccensis is useful for predicting its population dynamics. Age-stage, two-sex life tables of the predator, C. malaccensis, reared on Acarus siro were constructed under laboratory conditions at 22, 24, 28, 30, and 32 °C, 75% relative humidity, and a 0:24 h (L:D) photoperiod. Increasing temperature shortened the development time of the immature stages. The complete generation time of C. malaccensis ranged from 11.10 d to 27.50 d. Life table parameters showed that 28 °C was the optimum temperature for the growth and development of C. malaccensis; populations could increase rapidly at this temperature. The highest net reproductive rate (R0 = 290.25) and highest fecundity (544.52) occurred at 28 °C. Temperature significantly affected the intrinsic rate of increase (r), fecundity, and finite rate of increase (λ). The values of age-specific fecundity (high to low) were 28 °C > 24 °C > 30 °C > 32 °C > 22 °C, while the values of age-stage-specific fecundity had the same trend.

Selective biorational treatments for managing the storage mites, Tyrophagus putrescentiae (Schrank) and Aleuroglyphus ovatus (Troupeau) under laboratory conditions

Mites have lately emerged as economically important pests of stored products. Recently, addition of natural origin compounds individually or as a combination with predators have provided a considerable value for controlling these pests. In this study, the efficacy of the bacterium-derived pesticides, spinosad and spinetoram, and the combination of each of them with the predator Cheyletus malaccensis Oudemans was evaluated against two storage mite pests, Tyrophagus putrescentiae (Schrank) and Aleuroglyphus ovatus (Troupeau) under optimal abiotic conditions for pest development. After 21d, the terminal density was estimated for both astigmatid mite species exposed to diet (experiment I) treated with either spinosad or spinetoram (concentrations range of 0.01-2 ppm). Estimation was also done with diet (experiment II) treated with either spinosad or spinetoram (0.5 ppm) and/or the predator at initial predator/prey ratio (0.02). The density of predator was also determined after 21 days. Application of spinosyns significantly reduced population of T. putrescentiae and A. ovatus. The reduction potential increased with increasing concentration. Complete control of T. putrescentiae and A. ovatus was achieved by the application of spinosad at 1 and 2 ppm, respectively. As measured by rC50 and rC90 (concentration for 50% and 90% suppress of population in comparison to control), spinosad was more toxic to T. putrescentiae and A. ovatus than spinetoram. Furthermore, T. putrescentiae was more susceptible to spinosad than A. ovatus. Conversely, it was less susceptible to spinetoram than A. ovatus. The populations of both mite species were successfully suppressed by the sole application of C. malaccensis. Although the density of predatory mites was not affected by the presence of 0.5 ppm spinosad, it was almost eradicated by spinetoram at 0.5 ppm. A combination of spinosad at 0.5 ppm with two individuals of C. malaccensis mites (ratio 0.02) outperformed spinosad used alone at the same former concentration in reduction efficiency of the pest populations by 12% for T. putrescentiae and 25% for A. ovatus within 21 days.

Mite fauna (Acari) associated with the poultry industry in different laying hen management systems in Southern Brazil: a species key

This study is based on results from a large project on the mite diversity in commercial laying hen systems in Brazil. It aims to identify potential biocontrol agents amongst mites present in poultry farms, with a focus on one feather mite pest Megninia ginglymura. A secondary goal is to provide an operational identification tool to help the development of biological control in poultry farms. Sampling was conducted from August 2013 to August 2014, with 43 sampling events, in three different laying hen management systems. We used traps, laying hen feathers, and abandoned wild bird nests to collect the mites. A total of 38,862 mites belonging to 23 families and 39 species were found, including 17 species exclusively found in traps, six in wild bird nests, and one in feathers. The most abundant and frequent ectoparasitic species was M. ginglymura (76.3%; observed in all management systems). Amongst other mites, Tydeidae showed the highest richness with five species (Brachytydeus argentinensis (Baker, 1970), Brachytydeus australensis (Baker, 1970), Brachytydeus obnoxia (Kuznetzov and Zapletina, 1972), Brachytydeus oregonensis (Baker, 1970), and Brachytydeus tuttlei (Baker, 1965)), followed by Cheyletidae with four species (Chelacheles bipanus Summers and Price, 1970, Cheyletus eruditus (Schrank, 1781), Cheyletus malaccensis (Oudemans, 1903), and Cheletomimus (Hemicheyletia) wellsi (Baker, 1949)). Potential predatory species for biological control were C. malaccensis (9.4%), Typhlodromus transvaalensis (Nesbitt, 1951) (0.8%), Blattisocius keegani (Fox, 1947) (0.7%), and Blattisocius dentriticus (Berlese, 1918) (0.4%). A dichotomous key is provided to identify 48 species dwelling in Brazilian layer farms.