Mite pockets of lizards, a possible means of reducing damage by ectoparasites

Many scattered lizard groups have small skin invaginations in such places as the neck, axilla, groin and postfemoral region. These frequently contain feeding chiggers (the larvae of trombiculid mites) which, in general, are much commoner on species with pockets than on those without. Mite pockets appear to have evolved many times, being found in at least five families (Iguanidae, Chamaeleonidae, Gekkonidae, Lacertidae, Scincidae) and are most abundant in warm areas that are not extremely dry. They are present in newly hatched animals and embryos of viviparous forms and so cannot be produced in direct response to the mites. Typically, the epidermis of infested pockets is hyperplastic and resilient, rapidly repairing damage caused by feeding mites, and the dermis contains dense concentrations of lymphoid cells. It is suggested that mite pockets have evolved in forms prone to trombiculid infestation and ameliorate the damage that this causes by concentrating chiggers in places that are equipped to minimize the harm they do.     

A molecular phylogeny of the temperate Gondwanan family Pettalidae (Arachnida,Opiliones, Cyphophthalmi) and the limits of taxonomic sampling

We evaluate the phylogenetic and biogeographical relationships of the members of the family Pettalidae (Opiliones, Cyphophthalmi), a textbook example of an ancient temperate Gondwanan taxon, by means of DNA sequence data from four markers. Taxon sampling is optimized to cover more than 70% of the described species in the family, with 117 ingroup specimens included in the analyses. The data were submitted to diverse analytical treatments, including static and dynamic homology, untrimmed and trimmed alignments, and a variety of optimality criteria including parsimony and maximum‐likelihood (traditional search and Bayesian). All analyses found strong support for the monophyly of the family Pettalidae and of all its genera, with the exception of Speleosiro, which is nested within Purcellia. However, the relationships among genera are poorly resolved, with the exceptions of a first split between the South African genus Parapurcellia and the remaining species, and, less supported, a possible relationship between Chileogovea and the other South African genus Purcellia. The diversification of most genera is Mesozoic, and of the three New Zealand genera, two show evidence of constant diversification through time, contradicting scenarios of total submersion of New Zealand during the Oligocene drowning episode. The genera Karripurcellia from Western Australia and Neopurcellia from the Australian plate of New Zealand show a pattern typical of relicts, with ancient origin, depauperate extant diversity and recent diversification. The following taxonomic actions are taken: Milipurcellia Karaman, 2012 is synonymized with Karripurcellia Giribet, 2003 syn. nov. ; Speleosiro Lawrence, 1931 is synonymised with Purcellia Hansen & Sørensen, 1904 syn. nov . The following new combinations are proposed: Parapurcellia transvaalica (Lawrence, 1963) comb. nov. ; Purcellia argasiformis (Lawrence, 1931) comb. nov .     

Distribution and influence of grazing on wheat curl mites (Aceria tosichella Keifer) within a wheat field

Wheat streak mosaic virus (WSMV) is a serious disease of wheat and is primarily transmitted from infected to healthy plants by the wheat curl mite, Aceria tosichella Keifer. Although wheat is the primary plant host of A. tosichella, wheat curl mites have been recorded on more than 60 different plant hosts; this broad host range allows mites to survive outside the wheat‐growing season by providing a ‘green bridge’. Despite the fact that A. tosichella can only crawl short distances, the mites can disperse via wind and thus have the capacity to readily infest wheat crops from neighbouring refuges. In this study, we undertook field trials to investigate the temporal movement of A. tosichella, as well as the importance of wind and livestock grazing on mite dispersal late in the cropping season. We demonstrate there is a window in spring when A. tosichella undergo significant movement in south‐eastern Australia, and this is likely related to the development stage of wheat plants, and may also be influenced by wind direction. We found that grazing wheat crops reduced mite numbers, suggesting that any increase in WSMV issues in ‘grain and graze’ crops is likely due to the longer season wheat varieties used in these systems rather than the direct effects of grazing. These results emphasize the importance of crop management strategies in the control of A. tosichella.     

Two new species of the genus Zercon C. L. Koch from the Inner Aegean Region of Turkey (Acari: Mesostigmata: Zerconidae)

Two new species of the mite genus Zercon C. L. Koch, 1836 have been found: Zercon ekizi sp. n. and Zercon emirdagicus sp. n. are described and illustrated from female specimens collected in Afyonkarahisar and Kütahya provinces, Turkey. The similarities and differences between the related species are discussed.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:7388D199-2D1D-49F7-9747-4F49E8810067     

以实验种群生命表评价六种植绥螨对西花蓟马的控制潜力

【目的】植绥螨是蓟马等害虫(螨)的重要捕食性天敌,在当前生物防治中应用广泛,本研究旨在为本地植绥螨资源的开发利用及筛选出控制西花蓟马Frankliniella occidentalis最有效的植绥螨天敌提供依据。【方法】以西花蓟马为猎物,在室内温度(25±1)℃、光照16L︰8D、相对湿度80%±5%的条件下,比较了内蒙古本地植绥螨种类有益真绥螨Euseius utilis Liang et Ke、苏氏副伦绥螨Paraseiulus soleiger Ribaga和巴氏新小绥螨Neoseiulus barkeri Hughes及目前应用的植绥螨斯氏钝绥螨Amblyseius swirskii Athias-Henriot、东方钝绥螨A.orientalis Ehara和黄瓜新小绥螨N.cucumeris Oudemans取食西花蓟马后的发育历期和生殖潜力,并组建了实验种群生命表以评价各类植绥螨的捕食潜能。【结果】有益真绥螨的日均产卵量(1.67±0.02)粒和黄瓜新小绥螨的日均产卵量(1.58±0.06)粒相近且无显著差异,仅次于斯氏钝绥螨(1.69±0.07)粒;有益真绥螨其子代雌雄性比与黄瓜新小绥螨的性比也相同(1.63︰1),低于斯氏钝绥螨(1.77︰1)和巴氏新小绥螨(1.64︰1);有益真绥螨的世代平均周期最短(T=19.36 d),内禀增长率(rm=0.16)和周限增长率(λ=1.17)均最大,种群倍增时间最短(t=4.33 d)。【结论】有益真绥螨以西花蓟马为食后种群数量增长的潜力强于其他5种植绥螨,是本地防治西花蓟马较有潜力的植绥螨种类。     

Next generation sequencing of Apis mellifera syriaca identifies genes for Varroa resistance and beneficial bee keeping traits

Apis mellifera syriaca exhibits a high degree of tolerance to pests and pathogens including varroa mites. This native honey bee subspecies of Jordan expresses behavioral adaptations to high temperature and dry seasons typical of the region. However, persistent honey bee imports of commercial breeder lines are endangering local honey bee population. This study reports the use of next‐generation sequencing (NGS) technology to study the A. m. syriaca genome and to identify genetic factors possibly contributing toward mite resistance and other favorable traits. We obtained a total of 46.2 million raw reads by applying the NGS to sequence A. m. syriaca and used extensive bioinformatics approach to identify several candidate genes for Varroa mite resistance, behavioral and immune responses characteristic for these bees. As a part of characterizing the functional regulation of molecular genetic pathway, we have mapped the pathway genes potentially involved using information from Drosophila melanogaster and present possible functional changes implicated in responses to Varroa destructor mite infestation toward this. We performed in‐depth functional annotation methods to identify ～600 candidates that are relevant, genes involved in pathways such as microbial recognition and phagocytosis, peptidoglycan recognition protein family, Gram negative binding protein family, phagocytosis receptors, serpins, Toll signaling pathway, Imd pathway, Tnf, JAK‐STAT and MAPK pathway, heamatopioesis and cellular response pathways, antiviral, RNAi pathway, stress factors, etc. were selected. Finally, we have cataloged function‐specific polymorphisms between A. mellifera and A. m. syriaca that could give better understanding of varroa mite resistance mechanisms and assist in breeding. We have identified immune related embryonic development (Cactus, Relish, dorsal, Ank2, baz), Varroa hygiene (NorpA2, Zasp, LanA, gasp, impl3) and Varroa resistance (Pug, pcmt, elk, elf3‐s10, Dscam2, Dhc64C, gro, futsch) functional variations genes between A. mellifera and A. m. syriaca that could be used to develop an effective molecular tool for bee conservation and breeding programs to improve locally adapted strains such as syriaca and utilize their advantageous traits for the benefit of apiculture industry.     

Predatory — prey relationships in subtropical zooplankton: water mite against cladocerans in an Argentine lake

Summary In a small lake in northern Argentina pelagic water mite Piona sp. had the maximum of population density in January following with a five-day delay after the peak of zooplankton dominant — Daphnia laevis. The mite density was highly predicted by the previous variations of Daphnia density during 4 months of observation (December–March). Daphnia density was a negative delayed function of the predator density but only in December–January when Piona was abundant. During that period Daphnia death rate, d was also correlated with the mite density (r ²=0.80, P<0.005). In laboratory experiments water mites killed 1–7 Daphnia · predator^-1 · hour^-1 in a broad range of prey density. Another zooplankton component, Diaphanosoma birgei, was consumed at the same rates. The mite hardly consumed any copepods. In the pelagium during 24 hours the mite was more associated with Daphnia, than with Diaphanosoma, probably, because of the coincidence in photoreactions with Daphnia. Piona contribution to the death rates of its prey estimated by using the data on functional and numerical responses as well as by means of Edmondson-Paloheimo model, could reach 53% for Daphnia and 40% for Diaphanosoma. A computer experiment on the reconstruction of prey dynamics after subtraction of predator influence showed that the mite could have caused a depression in Daphnia numbers observed in the lake, but the declines in Diaphanosoma population were caused by other factors. After the removal of mite pressure model Daphnia population increased its average density 10-fold. Experiments on Piona feeding revealed a strong effect of interference among predators. This was eliminated by putting one mite per experimental vessel, which led to a 20-fold increase in predation rate. The effect explains the low feeding rates of Piona obtained by the previous authors who ignored the possibility of interference.     

New methods for the assessment of mite numbers and results obtained for several textile objects

Summary The assessment of mite numbers in textile objects is important with regard to measures aimed at mite control. The standard method is to take a dust sample and to separate the mites from the dust by means of flotation. The results of mite assessment can be improved using methods based on the natural mobility of the mites; the so-called Mobility Test makes use of the intrinsic movement tendencies of the mites, whereas the Heat Escape Method uses the mobility of the mites in connection with the effects of heat. An example concernig two jackets shows the difference in results of mite assessment when using the conventional method (dust sample and flotation) on the one hand, and the new methods (Mobility Test and Heat Escape Method) on the other. It is shown that the conventional method can only supply relative mite numbers. The new methods also enable the user to monitor more efficiently the use of acaricide agents in mite control. This is demonstrated using the example of two beds and a carpet taken from a children's bedroom. The considerably higher numbers of mites suggest that the risk of the occurence of mite allergens and their penetration into the indoor air is even greater than previously assumed.     

Dampness,mites and respiratory allergy

Summary This paper reviews the relationships between humidity, house-dust mites and respiratory allergy. In vitro relationship between relative humidity and house-dust mite growth are quite clear cut. In real conditions also, there is a significant association between relative humidity and the presence of live mites. The relevance of house-dust mites for respiratory allergy lies on clinical, physiopathological and mostly on epidemiological data. The latter demonstrate a correlation between exposure to mites and risk of sensitization and development of overt allergic diseases. Lastly, humidity of dwellings is linked to respiratory allergy. These results should lead to building safer dwellings for allergic subjects, or modifying existing dwellings. In this respect, emphasis should be put on a proper ventilation rate and also a proper behaviour of inhabitants in order to minimize humidity production.