Simulation of the interactions of predatoryTyphlodromus mites with the European red mite,Panonychus ulmi (Koch)

Interactions of Typhlodromus mites and their prey, the European red mite, in orchard settings were examined through computer simulation. In particular, the consequences of very slow dispersal by the predators, compared with the weather-dependent higher rates of prey dispersal, were elucidated. In simulations of the interactions of the predator and its prey, both dispersal and temperature strongly affected the available supply of juvenile prey, and thus could determine whether the predators on an individual tree survived or perished.     

感染人类的宠物螨病

螨病是一种由螨虫引起的非季节性、瘙痒性宠物皮肤病。此病可以发生于多种哺乳动物,尤其是家养宠物,偶尔会传染给与之接触的人类,并引起瘙痒和自限性皮炎。犬猫做为人类最主要的宠物,其皮肤可以藏匿几种螨虫,主要包括犬疥螨、猫背肛螨和姬螯螨,这些螨虫都是具有引发人兽共患病的潜在能力。与宠物密切接触的人一旦出现可疑皮肤病应该警惕螨病的存在。犬猫螨病的诊断应该基于直接发现螨虫,分析其形态和获取动物宿主临床症状。了解这些螨病的发病特点并做好适当预防是控制此类人兽共患病的关键。     

阜阳地区居室环境中粉螨的群落组成和多样性

目的调查安徽省阜阳地区居室环境中粉螨的群落组成和多样性。方法于2009年7月,选择100户家庭进行样本采集,每居室环境中取4个采样点,对采集到的地面灰尘、床面灰尘、家具灰尘及衣物灰尘进行粉螨的分离、鉴定、计数和数据分析。结果共检获粉螨3609只,隶属于6科15属,共19种。对4类居室灰尘中粉螨群落多样性分析表明:它们的丰富度指数为0.89~2.09,多样性指数为1.28~1.83,均匀度指数为0.65~0.71。结论粉螨群落的结构及多样性与其生境条件直接相关;阜阳地区人居环境粉螨孳生密度较高(48.5%),应加强防螨措施。     

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.     

Capture of mites and rotifers by four strains of Dactylella gephyropaga known as a nematophagous hyphomycete

Four strains of Dactylella gephyropaga obtained from Japan and Indonesia captured mites, as well as nematodes, by means of the adhesive hyphal network composed of columnar processes and rectangular meshes of hyphae, in which each of the meshes was made by additional growth of apex of a columnar process toward that of neighboring process and anastomosis with each other. This is the first report showing that a fungus captured and consumed mites. When immersed under water, the four strains captured rotifers also with the columnar processes by adhesion. The CBS178.37 used for comparison was not the strain of D. gephyropaga, and its adhesive network was produced only by repeating development and anastomosis of curved hyphae that captured neither mites and rotifers but only nematodes.     

Intranasal mite allergen induces allergic asthma-like responses in NC/Nga mice

Airway responses induced by intranasal administration of mite allergen without adjuvant were studied in NC/Nga mice. A crude extract of Dermatophagoides farinae (Df) was administered for 5 consecutive days and a single intranasal challenge booster dose was given 1 week after the last sensitization. 24 h after the single challenge, the airway hyperresponsiveness (AHR) was measured and the bronchoalveolar lavage fluid (BALF) was analyzed for numbers of eosinophils and neutrophils, and both cytokine and chemokine levels. There were marked increases in number of eosinophils in the BALF, AHR, Th2 cytokines (IL-5 and IL-13), and chemokine (eotaxin-1 and eotaxin-2) levels in the BALF following Df exposure. C57BL/6N, A/J, BALB/c, and CBA/JN mouse strains were also exposed to Df crude extract, but all of the measured responses were strongest in NC/Nga mice. Furthermore, Df-exposed NC/Nga mice showed the goblet cell hyperplasia, pulmonary eosinophilic inflammation, and increases in both total serum IgE and Df-specific IgG1. After intranasal exposure of NC/Nga mice to crude extract of Dermatophagoides pteronyssinus, the BALF eosinophilia and AHR were similar to responses induced by Df. None of the study parameters were increased in response to intranasal exposure to ovalbumin. These data demonstrated that NC/Nga mice developed allergic asthma-like responses after intranasal exposure to mite allergens.     

Acaricidal effects of natural six-carbon and nine-carbon aldehydes on stored-product mites

The toxicities of three plant volatiles, (2E)-hexenal, (2E, 6Z)-nonadienal and (2E)-nonenal, intermediate products of the oxylipin biosynthesis pathway, were tested on three mites of importance for medical purposes and as pests. The aldehydes were diluted in hexane separately and incorporated into diets in ranges of 4–143 mg g⁻¹. The final density of mites in control and aldehyde-enriched diets was compared after 21 days. The aldehydes were toxic to the mites, whose final density showed an inverse correlation with aldehyde concentration. In addition to the effects of aldehyde concentration, the final density of mites was also influenced by the different aldehydes tested and the interaction among aldehyde concentration and chemical structure. In a functional combination of aldehydes and species, the doses calculated for growth inhibition and eradication of mites ranged from 4 to 35 mg g⁻¹ and from 36 to 314 mg g⁻¹, respectively. Due to the protective role displayed by natural six-carbon and nine-carbon aldehydes, these compounds are potential candidates for controlling stored-product mites in stored food and feed products.     

Phenology and abundance of date palm mite Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) in Riyadh,Saudi Arabia

In the present study, we evaluated the effect of management practices, fruit season, host habitats (young and old fronds, date fruits and grasses), and temperature on the phenology and abundance of the date palm mite (DPM). The study was conducted in two date palm orchards (two plots each): a managed and an unmanaged plot. The phenology of DPM was assessed based on adult cumulative mite days (ACMDs), while mean mite density was used to assess the mite abundance on different host habitats. The ACMDs and mean mite density were significantly different between managed and unmanaged plots on different host habitats in both fruiting and off-seasons. The date fruits had highest ACMDs during fruiting season. While young fronds had significantly higher ACMDs than on old fronds an grasses during both seasons in both plots.. The temperature and season type significantly affected the mean density of DPM eggs and adults. There was a significant effect of host habitats mean density of DPM eggs and immatures. Based on the adult phenology and abundance of DPM, the mite overwinters in young fronds and aerial offshoots of infested date palm trees. These overwintering DPM caused the seasonal date fruit infestation, each year. Additionally, different phytophagous and predatory mites, which co-occur with DPM, and were found on different host habitats affected the phenology and abundance of DPM. Moreover, the change in DPM body color was related to the host habitat that they fed in. Exceptionally, the brown color of females collected during the winter season could be due to physiological changes due to low temperature. In DPM males collected from different host habitats throughout the study, some morphological variations in the width of the knob, height of the hook, and the angle between the knob axis and dorsal margin of the shaft were also recorded. The results of this study suggest that young fronds and grasses are the suitable sites for DPM survival and overwintering. Hence, the management practices, early in the fruit season and/or during off fruit winter months, should be directed towards these habitats. These could provide efficient reduction in seasonal infestation of DPM.     

Chemistry of the oil gland secretion of Collohmannia gigantea (Acari: Oribatida)

The chemistry of the lemon-scented oil gland secretion ofCollohmannia gigantea, a middle-derivative mixonomatanoribatid mite, was investigated by gas chromatography – massspectrometry.Gas chromatographic profiles of whole body extracts of C.gigantea revealed two distinct chromatographic zones, the firstcontaining a set of six volatile compounds, comprising the lemon-scentedmonoterpene aldehydes neral and geranial, the scented monoterpene ester nerylformate, a distinctly scented aromatic aldehyde(2-hydroxy-6-methyl-benzaldehyde= 2,6-HMBD), and the two non-scented hydrocarbons, tridecane and pentadecane.All six components appeared to be present in steady relative proportions inscenting mites only, indicating their unity within the scented secretion. Incontrast, the components of the second chromatographic zone were less volatileand found in both, scenting and non-scenting mites. Chemically, they representaset of fatty acids of already known cuticular origin.The secretion bouquet ofthe first chromatographic zone was linked with oil glands by histochemicalmeans: large amounts of aldehydes were present only in oil gland reservoirs,notin any other region of the mite body. While chemical profiles of oil glandsecretions of several dozen astigmatid mites are known, only one other oribatidoil gland composition, from a desmonomatan species, has been elucidated, beingalmost the same as that of C. gigantea. Moreover, allcomponents of these two secretions are widely distributed amongst astigmatidmite species and may also be common in a restricted set of middle-derivativeoribatids. These findings are consistent with the idea of astigmatid miteoriginfrom a mixonomatan-desmonomatan group.     

Phytoseiid Mites on Unsprayed Apple Trees in Oregon, and Other Western States (USA): Distributions, Life-Style Types and Relevance to Commercial Orchards

In unsprayed apple trees in eastern Oregon, Galendromus flumenis (Chant), Galendromus occidentalis (Nesbitt), Typhlodromus caudiglans Schuster and Metaseiulus citri (Garman and McGregor) were common phytoseiid mites; common plant-feeding mites were the eriophyid, Aculus schlechtendali Nalepa, the brown mite, Bryobia rubrioculus (Scheuten) and Eotetranychus spp.; apple rust mites seemed to be the primary prey for phytoseiids; the spider mites, Tetranychus urticae Koch and Panonychus ulmi (Koch) were scarce except for a few local outbreaks; the stigmaeid Zetzellia mali (Ewing) was at 10% of sites and its densities were inversely related to phytoseiid densities; phytoseiids were absent at some sites, particularly at high elevations where winters are severe. In seven Oregon ecoregions, G. flumenis was often at lower elevations in valleys with moderate winters; T. caudiglans was often at higher elevations; G. occidentalis was often at intermediate elevations, in young trees, and near where pesticides were used; it dominated in unsprayed trees only in almost treeless, sage-covered areas; M. citri was usually in older apple trees near agriculture. In mixed phytoseiid populations, M. citri, a generalist, and G. occidentalis, a specialist, occurred more often than expected; G. occidentalis was mostly found with T. caudiglans, a generalist; G. flumenis, a generalist, occurred less with others, possibly because it competes with both specialists and generalists. Analyses of species' distributions with multiple regression and genetic models gave explanatory r2s of 0.019-0.318. Of 29 variables, altitude of site, intensity of agricultural management, tree age, plant types, and Z. mali levels helped explain phytoseiid species presence. In the western USA, G. flumenis dominated in middle-southern latitudes; T. caudiglans dominated in the north near the Canadian border; G. occidentalis dominated in middle latitudes in parts of Washington, Idaho, Montana, and Wyoming; M. citri was at a few sites in these four states. Distributional and independent variable data were used to predict species presence at sites in Oregon with a 70% success rate. We discuss phytoseiid life-style types, community dynamics, presence in organic/conventional orchards, and trends as more selective IPM methods are used in apple orchards.