贵州软滑水螨属二新种记述：（蜱螨亚纲：软滑水螨科）

本文描述软滑水螨科Pionidae二新种。新种多盘软滑水螨Pipma polyacetabula sp.nov.以其两性具极多殖吸盘(雄螨68—72个,雌螨45—50个)为其显著特征。新种宽殖软滑水螨P.platyura sp.nov.两性殖吸盘数目较多(雄螨35—42个,雌螨约48个),两性殖吸盘板宽近与Ⅳ足基节板等宽。两新种间以雄性殖吸盘数差异显著;两新种亦以殖吸盘数与本属已知种有显著差异而易于鉴别。     

5种寄生蚌螨COI基因片段序列及系统发育分析

采用PCR技术对5种寄生蚌螨COI基因片段进行序列测定.序列分析的结果表明,比对后的序列总长度均为658 bp;其中A、G、C、T 4种碱基的平均含量分别为34.6%、20.2%、14.3%、30.9%,平均嘧啶含量（65.5%）明显高于嘌呤含量（34.5%）,说明碱基存在偏向性.弯弓蚌螨Unionicola arcuata与Y纹蚌螨U.ypsilophora 的种间遗传差异为26.4%,达到属间分类水平,结果支持Vidrine将沃蚌螨亚属从寄蚌螨亚属中分离的修订;螫爪蚌螨U.chelata与敏捷蚌螨U.agilex之间遗传差异为23.3%,达到属间分类水平,结果支持文春根等将敏捷蚌螨与其姊妹种腰蚌螨U.lumbaria放入韦蚌螨亚属中的修订.以营自由生活的厚蚌螨U.crassipes作为外类群,使用PAUP4.0b 10软件中的最大似然法（ML）和邻接法（NJ）构建系统树,结果显示：在5种寄生蚌螨中敏捷蚌螨可能是最早从祖先种分化出来的种;弯弓蚌螨与Y纹蚌螨可能起源于蚌螨属的同一个祖先.     

中国蚌螨属水螨一新种记述(蜱螨亚纲,蚌螨科)

记述了从我国江西省淡水蚌中采到的蚌螨科Unioncolidae水螨1新种,簇刺蚌螨U.(Anodontinatax)penicillatus sp.nov.,模式标本保存于南昌大学生物科学工程系.簇刺蚌螨,新种Unionicola(Anodontinatax)penicillatus sp.nov.(图1～11)正模♂,副模1♀,江西鄱阳湖,1998-11-11,文春根采自背角无齿蚌A.woodiana woodiana(Lea).鉴别特征新种近似于中间蚌螨U.(Anodontinatax)intermedia(Koenike,1882),但通过以下特征区别后者:雄螨具有背小板,雄螨Ⅳ-L-4-5的密刺毛数量为8～10和22～24(后者为18～20和17～19),射精复合体的形状和须肢的分叉腹小爪.词源:拉丁词"penicillatus"意思为"一簇毛的",指新种因雄螨Ⅳ-L-4-5有一簇刺毛而命名.     

分子鉴定背瘤丽蚌中弯弓蚌螨的隐藏种

Unionicola sp.与弯弓蚌螨U.arcuata在形态结构上非常相似,为了鉴别弯弓蚌螨U.arcuata 和Unionicola sp.,本研究扩增出Unionicola sp.12S rRNA的部分基因片段,与基因数据库中5种寄生蚌螨序列进行比较分析.结果显示,Unionicola sp.与弯弓蚌螨U.arcuata遗传差异为0.145,而分子系统树表明,Unionicola sp.与弯弓蚌螨U.arcuata聚为一支,具较近的亲缘关系.我们推断Unionicola sp.是弯弓蚌螨U.arcuata的1个隐藏种.这可能是由于不同寄主蚌造成了宿主隔离,从而引起了蚌螨遗传基因的分化.     

蚌螨腺毛和足爪的亚显微结构观察

利用扫描电镜分别对6种蚌螨的腺毛和足爪结构进行了观察,结果表明蚌螨的腺毛是由腺体、围腺片、刚毛和腺毛板共同构成的复合结构;对弯弓蚌螨的连续切片的观察表明,腺体是从体表延伸至体腔的消化道附近,由此认为蚌螨的腺体是由体壁皮层细胞演化而来。蚌螨足末除了爪外,还观察到跗节端部背面或腹面有体壁突及刚毛,因此,蚌螨足的步行结构不是仅由爪形成的简单结构,而是由爪、跗节末端背突或腹垫和刚毛组成的复合体。     

中国蚌螨属1新种及1新纪录种记述（蜱螨亚纲：水螨群：蚌螨科）

记述采自江西的蚌螨属1新种,定名为丰城蚌螨Unionicola(Parasitatax)fengchengensis sp.nov.和1个中国新纪录种。     

中国多毛腺水螨亚属两新种记述(蜱螨亚纲,水螨群,腺水螨科)

记述了中国腺水螨科Lebertiidae腺水螨属Lebertia腺水螨亚属Pilolebertia两新种拟刷毛腺水螨Lebertia(Pilole-bertia)pseudociliata sp.nov.和蓖齿毛腺水螨Lebertia( Pilolebertia)pectinata sp.nov.前者体壁具细致刻纹,E1具2毛状表皮突,P-Ⅱ腹毛长以及EpⅣ侧缘弧形等特征将之与其他种明显区分开;后者体壁具细致刻纹和具缘毛的P-Ⅱ腹毛可以将之与其他种类明显区分.文中对其腺毛和眼毛的体位特征做了详细描述.     

革螨一新属新种及一新科的建立(蜱螨亚纲:革螨股)

在云南陇川县的蜣螂体上采得一种革螨系未曾描述过的新种,并为之建立新科与新属,用其颚角呈球形膨大及躯体角化较深的特征命名。球革螨科新科Bulbogamasidae fam.nov.的主要特征:叉毛三叉,其侧具一拇指状薄膜;颚角呈球形膨大,角化弱;头盖前缘光滑;雄螨足11具强大的距状表皮突。球革螨属新属Bulbogamasus gen.nov.的主要特征:背板整块;背毛26对,板周围的长大,中部的细小;胸叉叉丝末端具刺状突,小分支端部有的分叉;雌螨具腹肛板与肛前毛;雄螨导精趾粗长,超过螯钳长的2倍以上。模式种为中华球革螨新种Bulbogamasus sinicus sp.nov.     

坚体螨属在我国首次发现：（蜱螨亚纲：犹伊螨科）

坚体螨属Iphidosoma Berlese 于1892年根据I. fimetarium (Muller, 1859)的后若虫而建立,属中仅1种发现雌螨,其余均只找到后若虫。其主要特征是:躯体骨化强;胸板宽大,具清晰网纹;螯钳定趾具透明膜状突起,其顶端尖;有些种类在颚基、足基节上,有时在胸板上具棘状刚毛,此种刚毛的末端圆钝或尖突。     

拱殖嗜渣螨各发育阶段的体表形态观察

【目的】观察和认识拱殖嗜渣螨Chortoglyphus arcuatus不同发育阶段主要外部形态特征及超微结构。【方法】用啤酒酵母粉纯化饲养拱殖嗜渣螨,选取不同发育阶段个体清洁后,分别利用体视显微镜、光学显微镜以及扫描电子显微镜对螨体颜色、形态特征、局部特征以及超微结构进行观察。【结果】成螨颜色为鲜明的淡棕红色,其他发育阶段均为乳白色。躯体硬,卵圆形。无背横沟划分前足体和后半体。螯肢发达,螯钳剪状,有纵纹,具明显的齿。外顶毛有栉齿。颚体基部腹面有细横纹。体躯刚毛短,光滑。雌螨生殖孔位于Ⅲ和Ⅳ基节之间,覆有骨化的生殖板。生殖板后缘光滑、弓形。雄螨阳茎位于Ⅰ和Ⅱ基节之间,长且弯曲、管状。有肛吸盘,漏斗状。有跗节吸盘。【结论】本研究补充了拱殖嗜渣螨文献未记载的一些特征,如卵、幼螨和若螨体色,螯肢背面和颚体腹面刻纹等,有助于该螨及其近缘种的快速鉴定和分类研究。     

Genetic differences among host-associated populations of water mites (Acari: Unionicolidae: Unionicola): allozyme variation supports morphological differentiation

Unionicola poundsi and U. lasallei are recognized as closely related, morphologically distinct species of water mites living in symbiotic association with the mussels Villosa villosa and Uniomerus declivus, respectively. However, results of a transplant experiment suggested that the morphological characters used to separate these species are plastic and are influenced by the host species in which these mites metamorphose. These results indicate that U. poundsi and U. lasallei are variants of the same species. To test the validity of these contrasting notions, the genetic structure of mite populations from Uniomerus declivus and V. villosa was compared. An examination of allozyme variation at 9 enzyme loci revealed a high degree of genetic differentiation between these host-associated populations, with mites from U. declivus and V. villosa being fixed for different alleles at 3 loci and exhibiting significant allele heterogeneity at 71% of their polymorphic loci. Coefficients of genetic similarity and genetic distance for mites from U. declivus and V. villosa were 0.36 and 0.95, respectively. The results of this study suggest that mite populations from U. declivus and V. villosa are genetically distinct and complement morphological data recognizing them as valid species.     

Review Geographic differences in host specialization between the symbiotic water mites Unionicola formosa and Unionicola foili (Acari: Unionicolidae)

The host specificity and population genetic structure of the symbiotic water mites Unionicola foili from the host mussel Utterbackia imbecillis and Unionicola formosa from the mussels Pyganodon cataracta, Pyganodon grandis and Anodonta suborbiculata were examined over a broad geographical scale in order to determine the extent to which specialization by these water mites is structured geographically. The behavioural responses of U. foili and U. formosa were highly host-species specific, with adults of both species exhibiting negative phototaxis in the presence of a chemical factor from the species of mussel with which the mites had been associated in the field. The photobehaviour of these water mites in the presence of water from a non-host mussel varied depending on the species in question. Although U. foili from U. imbecillis exhibited negative phototaxis in water modified by A. suborbiculata, mites from this latter host did not exhibit a directional response in U. imbecillis water. Unionicola foili and U. formosa from A. suborbiculata were positively phototactic when they were exposed to water modified by either species of Pyganodon. The photoresponse of U. formosa from P. cataracta and P. grandis was positive in the presence of water modified by U. imbecillis and A. suborbiculta. However, these mussel-mites showed no directional response in water modified by their alternate species of Pyganodon. Unionicola foili and the host-associated populations of U. formosa were examined for allozyme variation at eight loci to determine the pattern and degree of genetic variation. There was a high degree of genetic differentiation when mite populations from the two species of Pyganodon were compared with U. foili or U. formosa from A. suborbiculata. These populational groupings were fixed for different alleles at two enzyme loci. The results of this study indicate that populations of U. formosa from P. cataracta and P. grandis are reproductively isolated from U. foili from U. imbecillis and from U. formosa from A. suborbiculata and contend that host specificity is an important mechanism in restricting gene flow among these populational groupings. Furthermore, this study indicates that specialization among unionicolid water mites can vary geographically, owing to differences in geographic distribution of available hosts and differences in host use.Exp Appl Acarol 22: 683697 © 1998 Kluwer Academic Publishers     

Host specificity among Unionicola spp. (Acari: Unionicolidae) parasitizing freshwater mussels

Water mites of Unionicola spp. are common parasites of freshwater mussels as adults, living on the gills, or mantle and foot of their hosts and using these tissues as sites of oviposition. The present study addresses specialization among North American Unionicola mussel-mites using 2 measures of host specificity: (1) the number of host species used by a species of mite; and (2) a measure that considers the taxonomic distinctness of the hosts utilized by mites, weighted for their prevalence in the different hosts. Results of this study indicate the Unionicola spp. mussel-mites are highly host specific, with most species occurring in association with 1 or 2 species of hosts. If 2 or more host species are utilized, they are typically members of the same genus. These data are consistent with studies examining the dispersal abilities and host recognition behavior for members of the group. When the average values of host specificity for Unionicola subgenera were mapped on a phylogenetic tree for these taxa, a clade comprised of gill mites appeared to be more host specific than a clade consisting of mantle mites. There were, however, no apparent patterns of host specificity within each of the clades. Differences in specificity between the 2 lineages may reflect either a long evolutionary history that gill mites have had with host mussels or the intense competition among gill mites for oviposition sites within unionid mussels, leading to increased host specialization.     

Guild structure in water mites (Unionicola spp.) inhabiting freshwater mussels: choice,competitive exclusion and sex

Summary Unionicolid water mites inhabit freshwater unionid mussels during the nymphal and adult stages of their life-cycle. Regular sampling of mussels from two sites in St. Mark's River, Fl. established that each of four species of water mite (Unionicola abnormipes, U. fossulata, U. serrata and U. formosa) occurred mainly in one or two of the mussel species available at each site.The role of preference for particular mussel species during host location was assessed for the first three mite species by choice experiments, in which mites were offered different mussel species simultaneously. In five out of six experiments, mites entered normally unused mussels as often as they did normally used ones. Additionally, a sexual difference in choice was found for U. fossulata, with males preferring one mussel species and females showing no preference. One mussel species, (Anodonta imbecilis), normally unused but chosen by mite species during the lab. experiments, is inhabited exclusively by the fourth mite species, U. formosa, in the field. An experiment showed that U. formosa excludes other mite species aggressively from Anodonta imbecilis.The results illustrate the sometimes misleading nature of simple sampling data as an indication of host specificity or host preference in parasites. They suggest also that the population dynamics of some parasites might be more fruitfully compared to unrelated, free-living species than to other parasites.     

Occurrence of protandry and a female-biased sex-ratio in a sponge-associated water mite (Acari: Unionicolidae)

The sex ratio of aUnionicola crassipes-type mite from a pond in Alberta, Canada, was found to be significantly female-biased at the time of adult emergence. Male mites emerged earlier, but were later surpassed in number by the females. This protandry seems more likely to be due to the smaller size of the males and hence their faster developmental rate than to any mating advatage the male mites gain by early emergence. It is possible that group selection acting on the productivity of mite colonies with different proportions of low-sex-ratio producers has selected for female-bias. Water mites are not known to exhibit any atypical modes of reproduction (e.g.arrhenotoky), nor is it known whether pre-adult maleU. crassipes have a greater mortality rate than females, so the mechanism behind the skewed ratio is not known.     

The symbiotic water mite Unionicola formosa (Acari: Unionicolidae) ingests mucus and tissue of its molluscan host

Unionicola formosa is a symbiotic water mite that passes most of its life cycle in the mantle cavity of freshwater mussels. Although mites of this genus are often referred to as parasitic, little is known about their nutritional biology. A few species reportedly pierce the gill of a host mussel and ingest tissue or hemolymph. The present study was undertaken to identify possible sources of nutrition for U. formosa. To determine if mites ingested particulate matter in the mucous strand produced by a mussel during feeding, mussels with resident mites were exposed to a suspension of fluorescent microspheres. There was no evidence that U. formosa ingested the beads. Histochemical staining did, however, indicate a mucous material present in the midgut of the mites. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic assays revealed a high molecular weight component, consistent with a mucopolysaccharide, present both in the mussel gill and the mites. Results from western blots and an immunoaffinity binding assay with antibodies against mussel gill tissue and hemolymph also indicated that mites ingested host tissue. Whereas U. formosa probably does not ingest particulate material acquired by its host's suspension feeding, it is apparent that this mite utilizes host mucus, gill tissue, or hemolymph for at least part of its nutrition.     

Random amplified polymorphic DNA analysis of kinship within host-associated populations of the symbiotic water mite Unionicola foili (Acari: Unionicolidae)

Kinship relations within populations of unionicolid water mites are not well known, owing to their complex life cycles and the fact that interactions between active and resting stages for some species are transitory. A number of species of unionicolid water mites are, however, obligate symbionts of freshwater mussels and spend most of their life cycle in association with these hosts. Among these species of mites, parents and offspring are more likely to co-occur and thus provide opportunities to address questions related to the structure of the mating system. The present study employs random amplified polymorphic DNA (RAPD) analysis to address kinship within populations of Unionicola foili living in symbiotic association with the host mussel Utterbackia imbecillis. DNA was amplified from adult mites and a representative number of eggs or larvae (n = 20-30) that were removed from mussels collected on three separate occasions (July, November, and March) over a 12-month period. Parsimony analyses of the molecular data for adults and progeny collected from mussels during July, November, and March revealed distinct groupings, that for the most part, corresponded to mites collected from each of the sampling periods. Many of the genetic markers obtained for male and female U. foili were not evident among the larvae or eggs, suggesting that adults obtained from a host mussel at the time of collection were not the parents of a majority of the progeny. However, female mites and eggs collected from mussels during March and November shared more markers than did females and progeny examined during July. Furthermore, many offspring in the July sampling period were found to have one or more parents absent from the sampled population. Overall, RAPD profiling appears to have limited usage in determining kinship within populations of U. foili, due to its recruitment patterns, and the relatively large number of adults and progeny per mussel. It may, however, prove to be a useful method for assessing genetic relatedness among unionicolid mussel-mites that have substantially lower population densities.     

蚌螨属1新种记述（蜱螨亚纲：蚌螨科）

报道蚌螨属Unionicola一新种。