455 resultados para Mite


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Hitherto, the Malaconothridae contained Malaconothrus Berlese, 1904 and Trimalaconothrus Berlese, 1916, defined by the possession of one pre-tarsal claw (monodactyly) or by three claws (tridactyly) respectively. However, monodactyly is a convergent apomorphy within the Oribatida and an unreliable character for a classification. Therefore we undertook a phylogenetic analysis of 102 species as the basis for a taxonomic review of the Malaconothridae. We identified two major clades, equivalent to the genera Tyrphonothrus Knülle, 1957 and Malaconothrus. These genera are redefined. Trimala-conothrus becomes the junior subjective synonym of Malaconothrus. Some 42 species of Trimalaconothrus are recom-bined to Malaconothrus and 15 species to Tyrphonothrus. Homonyms created by the recombinations are rectified. The replacement name M. hammerae nom. nov. is proposed for M. angulatus Hammer, 1958, the junior homonym of M. an-gulatus (Willmann, 1931) and the replacement name M. luxtoni nom. nov. is proposed for M. scutatus Luxton, 1987, the junior homonym of M. scutatus Mihelč ič, 1959. Trimalaconothrus iteratus Subías, 2004 is an unnecessary replacement name and is a junior objective synonym of Malaconothrus longirostrum (Hammer 1966). Malaconothrus praeoccupatus Subías, 2004 is a junior objective synonym of M. machadoi Balogh & Mahunka, 1969. Malaconothrus obsessus (Subías, 2004), an unnecessary replacement name for Trimalaconothrus albulus Hammer 1966 sensu Tseng 1982, becomes an available name for what is in fact a previously-undescribed species of Malaconothrus. We describe four new species of Tyrphonothrus: T. gnammaensis sp. nov. from Western Australia, T. gringai sp. nov. and T. maritimus sp. nov. from New South Wales, and T. taylori sp. nov. from Queensland. We describe six new species of Malaconothrus: M. beecroftensis sp. nov., M. darwini sp. nov. M. gundungurra sp. nov. and M. knuellei sp. nov. from New South Wales, M. jowettae sp. nov. from Norfolk Island, and M. talaitae sp. nov. from Victoria.

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The genus Austronothrus was previously known from three species recorded only from New Zealand. Austronothrus kinabalu sp. nov. is described from Sabah, Borneo and A. rostralis sp. nov. from Norfolk Island, south-west Pacific. A key to Austronothrus is included. These new species extend the distribution of Austronothrus beyond New Zealand and confirms that the subfamily Crotoniinae is not confined to former Gondwanan landmasses. The distribution pattern of Austronothrus spp., combining Oriental and Gondwanan localities, is indicative of a curved, linear track; consistent with the accretion of island arcs and volcanic terranes around the plate margins of the Pacific Ocean, with older taxa persisting on younger island though localised dispersal within island arc metapopulations. Phylogenetic analysis and an area cladogram are consistent with a broad ancestral distribution of Austronothrus in the Oriental region and on Gondwanan terranes, with subsequent divergence and distribution southward from the Sunda region to New Zealand. This pattern is more complex than might be expected if the New Zealand oribatid fauna was derived from dispersal following re-emergence of land after inundation during the Oligocene (25 mya), as well as if the fauna emanated from endemic, relictual taxa following separation of New Zealand from Gondwana during the Cretaceous (80 mya).

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This project expands upon the discovery that scabies mites produce protein molecules that interfere with the human complement cascade, disrupting a critical component of the early stages of the host immune response. This is believed to provide an optimal environment for the development of commonly associated secondary bacterial infections. The thesis investigated the effect of two distinct scabies mite proteins, namely SMS B4 and SMIPP-S I1, on the in vitro proliferation of Group A Streptococcus in whole human blood. Additionally, in vitro immunoassays were performed to determine if complement mediated opsonisation and phagocytosis were also disrupted.

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Two-spotted mite, Tetranychus urticae Koch, was until recently regarded as a minor and infrequent pest of papaya in Queensland through the dry late winter/early summer months. The situation has changed over the past 4-5 years, so that now some growers consider spider mites significant pests all year round. This altered pest status corresponded with a substantial increase in the use of fungicides to control black spot (Asperisporium caricae). A project was initiated in 1998 to examine the potential reasons for escalating mite problems in commercially-grown papaya, which included regular sampling over a 2 year period for mites, mite damage and beneficial arthropods on a number of farms on the wet tropical coast and drier Atherton Tableland. Differences in soil type, papaya variety, chemical use and some agronomic practices were included in this assessment. Monthly visits were made to each site where 20 randomly-selected plants from each of 2 papaya lines (yellow and red types) were surveyed. Three leaves were selected from each plant, one from each of the bottom, middle and top strata of leaves. The numbers of mobile predators were recorded, along with visual estimates of the percentage and age of mite damage on each leaf. Leaves were then sprayed with hairspray to fix the mites and immature predators to the leaf surface. Four leaf disks, 25 mm in diameter, were then punched from each leaf into a 50 ml storage container with a purpose-built disk-cutting tool. Disks from each leaf position were separated by tissue paper, within the container. On return to the laboratory, each leaf disk was scrutinised under a binocular microscope to determine the numbers of two-spotted mites and eggs, predatory mites and eggs, and the immature stages of predatory insects (mainly Stethorus, Halmus and lacewings). A total of 2160 leaf disks have been examined each month. All data have been entered into an Access database to facilitate comparisons between sites.

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An integrated pest management (IPM) strategy was developed to manage infestations of mould mite Tyrophagus putrescentiae (Schrank) in stored animal feed, due to the increasing importance of these mites as pests of feed processing and storage facilities in Australia. This strategy involved several aspects such as limiting the moisture content of the processed feed to 12%, admixing vegetable oil to some feed (2% w/w), strict hygiene practice in and around the processing and storage facility, and rejection of infested grain at the receiving point. Additionally, seven contact insecticides and the fumigant phosphine were evaluated for their effectiveness against the mould mite to assess their potential integration into the IPM strategy. Among them, pyrethrin synergised with piperonyl butoxide, the insect growth regulator s-methoprene and a newly developed bacterium-based material spinosad controlled the mites. Moreover, the fumigant phosphine at 1 mg/litre over a six days exposure period also controlled these mites. So far, the IPM strategy, without any involvement of insecticides or fumigant has resulted in a complete eradication of the mite population in this particular case of stored animal feed.

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In order to study the colonization and development of moss mites (Oribatida) communities in a Scots pine forest of a reclaimed limestone mine dump in Northern Poland, 3 plots from the dump were chosen. The selected plots differed in age, 5 years old, 35 and 50 years old. From a total of 30 samples 499 mites (Acari) were extracted in Tullgren funnel from which 262 were Oribatida. Abundance (N) was analyzed in all mites and after determining the species of both, juvenile and adult stages of oribatids, the following indices were analyzed: Abundance (N), Dominance (D), Species diversity (S), Species richness (s) and Shannon’s diversity index (H). Regarding to the results obtained; oribatid mites were dominant with the highest abundance in all assemblages (Plot 1: 139 Oribatida /299 Acari. Plot 2: 40/55 and Plot 3: 83/145). Tectocepheus velatus showed a very high dominance (45,99%) in plot 1; the highest value for Shannon’s diversity index belonged to plot 3. On the other hand, juvenile’s percentage was significantly higher than adult’s percentage, especially at plot 2 (95,02%). These results made us to conclude that the high abundance of oribatids in the youngest forest is due to T. velatus’s high abundance and that plot 3 is the best habitat for mites. Finally, the high occurrence of juvenile stages requires keeping on studying the area.

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Population dynamics of the water mite Unionicola arcuata were investigated in the freshwater bivalve Cristaria plicata during the period from January to December 2002 in Poyang Lake, East China. A pattern of seasonal variation was observed, with prevalence and abundance peaking in early spring and autumn. The number of mites in individual hosts was significantly correlated with the size, but not with the sex, of bivalves. The change in infection level of mites on different infection sites in C. plicata was significant, with > 58% of the mites found on the outer and inner gills, indicating that U. arcuata shows site preference.

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Despite a multitude of environmental stressors, the Varroa mite is still regarded as the greatest cause of honey bee mortality in its invaded range. Breeding honey bees that are resistant to the mite is an important area of research. This thesis aimed to gain a better understanding of the grooming and hygienic behaviours of Russian honey bees (RHB). The effect of a break in the synchrony of a mite’s life cycle on reproductive success was tested through brood inoculation experiments. Mites released by hygienic behaviour and forced to enter a new cell are less likely to lay male offspring. Through laboratory cage assays it was found that daughter mites are more susceptible to grooming behaviour. A new method of marking Varroa mites was developed which would enable a single cohort of mites to be followed after inoculation. A strong brood removal trait was noticed in RHB colonies, therefore they were tested for Varroa sensitive hygienic (VSH) behaviour. RHB demonstrated levels of VSH as high as the USDA line bred specifically for this behaviour. In addition the same QTL found to be responsible for the trait in VSH bees, was associated with VSH in RHB stock. Previous work showed that the ratio of older mites to total trapped mites (O/T) in the debris of honey bee colonies demonstrated the strongest association with colony infestation. This research showed that O/T is associated with VSH and brood removal behaviour. In addition, bees that displayed high levels of VSH in this study were also more likely to spend a longer amount of time grooming in laboratory assays. This indicates that both grooming and hygienic behaviours play important roles in the resistance of RHB stock. Their likelihood to be expressed by other stocks is discussed and recommendations for further research are provided.

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El tema de la bestia enamorada es frecuente en los cuentos de todas las culturas. No siempre se trata de un animal sino que el enamorado suele adoptar formas mostruosas y feroces. Partiendo del psicoanálisis, se ha demostrado la acción liberadora que ejercen los cuentos populares en la formación de la personalidad infantil y en la maduración de la afectividad, el enriquecimiento del lenguaje y la imaginación, la educación de la atención pero sobre todo la capacidad que poseen para favorecer el conocimiento y superar los propios problemas emocionales a través de recrearlos en los cuentos. El coraje es sin duda uno de los valores que con más insistencia ofrecen los cuentos populares: la aventura iniciática es siempre un reto, un riesgo a los ojos del protagonista para que sea capaz de correr las peripecias llenas de intriga que la historia le plantea. Pero sobre todo lo que es más destacable en los cuentos es que sus mensajes llegan a través de simples y cotidianas situaciones sociales, como el mito de la bestia enamorada sirve para cambiar la actitud de la mujer frente al sexo, para pasar del sentimiento de rechazo y miedo a la aceptación.

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