中国叶刺瘿螨亚科三新种三新记录种记述(蜱螨亚纲:瘿螨总科)

本文描述叶刺瘿螨亚科Phyllocoptinae的3个新种和3个新记录种，3个新种是：蓼四瘿螨Tetra polygoni Wei,sp.nov.、Cheng桐四瘿螨Tetra clerodendri Wei,sp.nov.和上思新顶背瘿螨Neotegonotus shangsiensis Wei,sp.nov.，所危害的寄主植物分别是：火炭母Polygonum chinense L.(Polygonaceae)、大青Clerodendrum cyrtophyllum Turcz.(Verbenaceae)和降真香Acronychia Pedunculata (L.)Mig(Rutaceae);3个新记录种是：桧平植羽瘿螨Platyphytoptus sabinianae Keifer、斑芒畸瘿螨Abacarus sacchari Channabasa-vanna和Siamina cruminae Boczek。     

中国叶刺瘿螨亚科一新亚属二新种记述(蜱螨亚纲:瘿螨总科)

本文记述的新亚属是新离子瘿螨亚属Neoleipothrix subgen.nov.,二个新种是海芋新离子瘿螨Neoleipothrix alocasiae sp.nov.和大血藤背纹瘿螨Notostrix sargentodoxae sp.nov.。     

荔枝瘿螨的为害及其防治方法

荔枝瘿螨在南宁地区每年出现二个虫口高峰,第一个高峰在5～6月;第二个高峰在9～10月。其为害引起落花、落果,着果率降低,被害枝着果率仅为健枝的42.4%,受害果重量减少10%～16%。新梢未萌发之前,螨体大部分集中在被害梢毛瘿内,其中又以鲜褐色毛毡螨量最多,其次为褐色毛毡。过冬瘿螨多群集在被害的夏梢及秋梢毛毡上。当新梢萌发刚露白时,瘿螨即从被害梢毛毡转移至新芽上。基于这一习性,在荔枝树未发新芽前剪除害梢是防治该螨的有效方法,较适合于幼树。药剂防治最好在新梢萌发时进行。     

农田土壤螨群落变化与环境因素关系的研究

对中国农业大学实验站农田土壤螨群落变化与环境因素的关系研究结果表明，土壤螨种类与数量随土壤养分的增加而增加，随土壤容重和pH值的增大而减少；长期施用EM堆肥，土壤孔隙多，通气性好，土壤耕层增厚，有机质含量提高，土壤螨种类与数量最多。     

农田土训螨群落变化与环境因素关系的研究

对中国农业大学实验站农田土壤螨群落变化与环境因素的关系研究结果表明,土壤螨种类与数量随土壤养分的增加而增加,随土壤容重和pH值的增大而减少;长期施用EM堆肥,土壤孔隙多,通气性好,土壤耕层增厚,有机质含量提高,土壤螨种类与数量最多。     

广西食螨瓢虫和黑囊食螨瓢虫的研究

通过系统调查和室内试验,明确了国营广西浪湾华侨农场和南宁市郊柑桔园中食螨瓢虫种类主要有广西食螨瓢虫、黑囊食螨瓢虫和越南食螨瓢虫等3种,其中以广西食螨瓢虫、黑囊食螨瓢虫为优势种。两优势种瓢虫在当地一年可发生9～10代,成虫的寿命最长达105天,每头雌虫一生平均产卵最多达117粒。成虫、幼虫均能捕食柑桔红蜘蛛,每头日捕食量与叶螨密度有关,密度越大捕食量越多。食螨瓢虫田间种群数量变动与食料和使用化学农药情况有关,红蜘蛛少或用药多的果园,常无这类瓢虫。     

三江平原农田地表和地下土壤螨群落空间自相关性研究

多尺度空间自相关性是土壤动物空间异质性和空间共存格局研究的重要基础。在中国科学院三江平原沼泽湿地生态实验站的农田内,以5 m为步长设置一个50 m×50 m的样地,结合全局Moran’s I和局部Moran’s I指数,研究地表、地下和地表—地下土壤螨群落多尺度空间自相关性特征。结果表明,地表和地下土壤螨群落的物种数量和平均密度均有显著差异。全局空间自相关性结果表明,除了地表螨群落,地下螨群落平均密度在8月(35~40 m)和10月(5~30 m)、地表—地下螨群落平均密度在8月(5~10 m和35~45 m)和10月(5~35 m)均有显著的多尺度全局空间自相关性,土壤螨群落中数量较多的优势和常见类群易形成明显的多尺度全局空间自相关性。局部空间自相关性结果表明,地表、地下和地表—地下螨群落及所有螨类的平均密度均存在显著的局部空间自相关性,形成"斑块"和"孔隙"并存的水平分布格局。本研究表明,多尺度全局空间自相关性是地下和地表—地下土壤螨群落的重要特征,群落和物种的平均密度均在局部地区形成"斑块"和"孔隙"并存的的水平分布格局。     

截形叶螨发育速率与温度关系模拟及对哒螨灵的抗性风险评估

为明确温度对截形叶螨抗哒螨灵种群(Py-R)和敏感种群(SS)风险发育速率的影响和评估截形叶螨对哒螨灵药剂的抗性风险,本试验在16℃、20℃、24℃、28℃、32℃和36℃6个温度梯度下,用王-兰-丁模型拟合了两个种群的世代发育速率与温度的关系曲线,并采用了数量遗传学中的域性状分析法,估算了截形叶螨对哒螨灵的现实遗传力并预测了不同选择压力下截形叶螨对哒螨灵的抗性风险。研究结果表明,根据拟合的王-兰-丁模型推导,截形叶螨敏感种群SS世代发育的最低、最高临界温度分别为10.05℃和39.24℃,抗性种群Py-R发育最低、最高临界温度分别为13.45℃和41.89℃;抗性种群各螨态的最高临界温度值均显著大于敏感种群,表明截形叶螨抗哒螨灵种群对高温的忍耐程度和适应能力大于敏感种群。估算出的截形叶螨对哒螨灵的抗性现实遗传力(h~2)为0.11,且抗性筛选前期和中期的h~2值为0.12和0.18,大于筛选后期h2值(0.08),在筛选末期,h~2值又回升到0.14。在室内选择条件(h~2=0.11)下,选择压力即杀死率为50%~90%时,预计抗性增长10倍,仅需10~23代;而在田间选择压力(h2=0.05)下,同样条件下,抗性增长也只需21~46代。因此,截形叶螨对哒螨灵存在一定的抗性风险,可与其他不具交互抗性的杀虫剂之间进行轮用,并降低选择压来延缓抗药性的产生。     

Assessing the relationship between patch type and soil mites: A molecular approach

An urgent need exists for indicators of soil health and patch functionality in extensive rangelands that can be measured efficiently and at low cost. Soil mites are candidate indicators, but their identification and handling is so specialised and time-consuming that their inclusion in routine monitoring is unlikely. The aim of this study was to measure the relationship between patch type and mite assemblages using a conventional approach. An additional aim was to determine if a molecular approach traditionally used for soil microbes could be adapted for soil mites to overcome some of the bottlenecks associated with soil fauna diversity assessment. Soil mite species abundance and diversity were measured using conventional ecological methods in soil from patches with perennial grass and litter cover (PGL), and compared to soil from bare patches with annual grasses and/or litter cover (BAL). Soil mite assemblages were also assessed using a molecular method called terminal-restriction fragment length polymorphism (T-RFLP) analysis. The conventional data showed a relationship between patch type and mite assemblage. The Prostigmata and Oribatida were well represented in the PGL sites, particularly the Aphelacaridae (Oribatida). For T-RFLP analysis, the mite community was represented by a series of DNA fragment lengths that reflected mite sequence diversity. The T-RFLP data showed a distinct difference in the mite assemblage between the patch types. Where possible, T-RFLP peaks were matched to mite families using a reference 18S rDNA database, and the Aphelacaridae prevalent in the conventional samples at PGL sites were identified, as were prostigmatids and oribatids. We identified limits to the T-RFLP approach and this included an inability to distinguish some species whose DNA sequences were similar. Despite these limitations, the data still showed a clear difference between sites, and the molecular taxonomic inferences also compared well with the conventional ecological data. The results from this study indicated that the T-RFLP approach was effective in measuring mite assemblages in this system. The power of this technique lies in the fact that species diversity and abundance data can be obtained quickly because of the time taken to process hundreds of samples, from soil DNA extraction to data output on the gene analyser, can be as little as 4 days.     

More sex at higher altitudes: Changes in the frequency of parthenogenesis in oribatid mites in tropical montane rain forests

We investigated changes in density, proportion of parthenogenetic species and individuals, and community structure of oribatid mites (Oribatida, Acari) along an altitudinal gradient in tropical montane rain forests in southern Ecuador. We hypothesized that the proportion of parthenogenetic species and individuals increases whereas density decreases with increasing altitude due to increased harshness of abiotic conditions known to favor parthenogenetic reproduction. In contrast to our hypothesis, the number of parthenogenetic species and individuals decreased toward higher altitudes indicating that changes in environmental conditions with altitude favor sexual rather than parthenogenetic reproduction. Low density of oribatid mites at high altitudes suggest that high frequency and density of sexual species is favored by the availability of resources and not by factors related to harsh abiotic conditions, finding mating partners or tight coupling with parasites or pathogens. Cosmopolitan decomposer taxa tended to be more frequent at higher altitudes indicating that these species are euryoecious. Overall, our data support the view that the reproductive mode of soil animals is predominantly controlled by the availability and accessibility of resources.     

Trophic stability of soil oribatid mites in the face of environmental change

A key issue in ecology is the degree to which trophic structure within communities responds to environmental change. Organisms with generalist diets are more flexible in their feeding habits than are specialists, and may be affected less in a changing environment. Soil fauna fulfill crucial ecosystem functions in terrestrial ecosystems and many are thought to have generalized diets. They may therefore be buffered from negative effects of environmental change. Here, we used ¹⁵N isotope analysis to study trophic differentiation among 91 species of oribatid mites and their responses to chronic atmospheric N deposition. Combining our own measurements with published data, we established that the trophic positions of mite species were remarkably stable within and among forests, as well as between ambient and experimental N deposition. Trophic stability indicates a higher than expected level of feeding specialization, which may foster diversity, but limit the ability to switch food resources in a changing environment.     

Vertical distribution of soil mites (Acari) in conventional and no-tillage agricultural systems

Summary Soil mite abundance was measured at four depths (0–5, 6.5–11.5, 13–18, and 19.5–24.5 cm) in agricultural plots under no-tillage or conventional tillage in Clarke County, Georgia, USA. The vertical distribution of mites was not significantly different between the two tillage systems: Most mites were found in the top 0–5 cm zone. This was the zone where greater moisture content occurred, and (in other studies) was the zone of maximum root biomass and microbial activity. Among mite suborders, only the Prostigmata were found in any abundance below 5 cm. Mite populations declined dramatically on occasions when the soil moisture exceeded field capacity, but did not appear to migrate vertically.Dedicated to the late Prof. Dr. W. Kühnelt     

不同寄主植物与斜纹夜蛾喜食程度、生长发育及存活率的关系研究

研究了不同寄主植物与斜纹夜蛾喜食程度、生长发育及存活率的关系结果表明 ,斜纹夜蛾喜食植物依次为槟榔芋 >莲藕 >甘蓝 >青菜 >水蕹菜 >黄牙白 >棉花 >大豆 >萝卜 >豇豆 >木耳菜 ;较喜食植物依次为花生 >芝麻 >酸模叶蓼 >四叶萍 >甘薯 >绿豆 >黄瓜 ;其余为次要寄主植物。斜纹夜蛾幼虫取食不同寄主植物 ,其发育历期、蛹重、蛹羽化出成虫比率均有显著差异 ,取食芋头、水蕹菜、青菜、甘蓝、豇豆和莲藕等作物叶片的幼虫发育历期较短 ,蛹较重 ,蛹羽化率较高 ,而取食棉花、大豆和向日葵叶片的幼虫历期相对较长 ,蛹较小 ,蛹羽化率相对较低。     

不同寄主植物烟粉虱种群数量消长及空间动态变化研究

对不同寄主植物烟粉虱(Bemisiatabaci)种群动态研究结果发现,不同寄主植物烟粉虱种群数量达高峰的时间有所差异,波幅也不一致,12种作物烟粉虱种群数量依次为油葵>西葫芦>棉花>大豆>南瓜>茄子>丝瓜>番茄>辣椒>黄瓜>菜豆>玉米,说明烟粉虱对其寄主植物具有一定的自然选择性。用扩散系数(C=S2/-X)对烟粉虱在棉花、油葵和大豆作物田空间分布型初步分析结果均为聚集分布型。     

A comparison of microarthropod assemblages with emphasis on oribatid mites in canopy suspended soils and forest floors associated with ancient western redcedar trees

Microarthropod abundance, oribatid mite species richness and community composition were assessed in the high canopy (ca. 35 m) of an ancient temperate rainforest and compared with microarthropod communities of the forest floor. Microarthropods were extracted from 72 core samples of suspended soils and 72 core samples from forest floors associated with six western redcedar trees in the Walbran Valley on the southwest coast of Vancouver Island, Canada. Total microarthropod abundances, mesostigmatid and astigmatid mites, Collembola and other microarthropod abundances were significantly greater in forest floors compared to canopy habitats. Oribatid and prostigmatid mite abundance were not significantly different between habitats. The relative abundances of all microarthropod groups considered in this study differed significantly between habitats. Eighty-eight species of oribatid mites were identified from the study area. Eighteen of the 53 species observed in suspended soils were unique to the canopy. Cluster analysis indicates that the arboreal oribatid mite community is distinct and not a taxonomic subset of the forest floor assemblage, however, canopy oribatid mite communities are more heterogeneous in species composition than in the forest floor.     

Exotics as host plants of the California butterfly fauna

Introduced species may impact native species and communities in many ways. One which has received relatively little attention is by serving as resources for natives, thereby altering their ecology. We address such impacts on the California butterfly fauna as currently understood. Eighty-two of California's approximately 236 butterfly species (34%) are reported as ovipositing or feeding on introduced plant taxa. Many more utilize introduced plants as nectar sources. Interactions with introduced plant taxa are not distributed evenly among butterfly species. Alpine and desert butterflies interact with relatively few introduced plants because few exotic plant species have reached and successfully colonized these habitats. Other California butterfly species are specialists on particular plant families or genera with no exotic representatives in California and have thus far failed to recognize any introduced plants as potential foodplants. Some California butterflies have expanded their geographic ranges and/or extended their flight seasons by feeding on exotic plants. However, negative impacts of exotic plant species can also occur. At least three of the state's butterfly species currently lay eggs on introduced taxa that are toxic to larvae. Impacts of introduced plant taxa on California's butterflies are expected to increase as both habitat conversion and alien introductions accelerate.     

黄土丘陵沟壑区抗侵蚀植物的初步研究

 土壤侵蚀作为山区生态系统退化最主要的驱动力,严重干扰着植被的发育演替过程,植被则通过采用不同的繁殖方式、形态与生理补偿等方式来克服和适应土壤侵蚀造成的负面压力,使植物本身对土壤侵蚀环境的适应性增强,继而发展成为可抵抗土壤侵蚀的植物和群落。凡具有适应土壤侵蚀环境能力,能在土壤侵蚀条件下生存,并能保护改良土壤和具有防止土壤侵蚀的作用,具有繁殖更新能力,可维持群落稳定与可持续发展的植物,称之为抗侵蚀植物。在对黄土丘陵沟壑区植被恢复中不同抗侵蚀植物进行分类、及其侵蚀学特征与土壤侵蚀环境演变特征分析的基础上,提出从土壤侵蚀学观点出发,对植被恢复过程中先后出现的植物和群落的形态学、生理学和生态学特征及防蚀功能进行系统研究,以更好地发挥植物和植被保持水土与改善环境的生态功能。