Wolbachia在山楂双叶螨中的感染及对寄主生殖的影响

【目的】共生菌Wolbachia在多种叶螨寄主中引起细胞质不亲和及适合度改变,影响寄主的生物学特性。山楂双叶螨Amphitetranychus viennensis是重要的果树害螨,常暴发成灾。本研究旨在明确Wolbachia在山楂双叶螨中的感染情况及对寄主生殖的影响。【方法】采集自然种群的山楂双叶螨,运用多位点序列分型技术（multilocus sequence typing, MLST）对其体内Wolbachia感染率及株系进行分析;通过杂交试验及生物学观察,分析感染Wolbachia对山楂双叶螨单雌产卵量、后代孵化率、性比及死亡率的影响。【结果】山楂双叶螨自然种群感染一种株系的Wolbachia （wVie）,该Wolbachia株系与小黑花椿象Orius strigicollis和丽蝇蛹集金小蜂Nasonia vitripennis中的Wolbachia株系亲缘关系较近,而与叶螨属Tetranychus叶螨感染的Wolbachia株系亲缘关系较远。Wolbachia与4种分化较小的线粒体单倍型相关联。Wolbachia感染雌虫与不感染雌虫产卵量没有显著差异（P>0.05）。不感染雌虫与感染雄虫交配,卵孵化率显著低于其他杂交组合 (P<0.05),但孵化率仍达近75%。各交配组合的后代性比及死亡率变化不明显（P>0.05）。【结论】Wolbachia在山楂双叶螨种群中的侵染历史较短,对山楂双叶螨的产卵力、后代性比、死亡率没有影响。Wolbachia在山楂双叶螨中诱导产生弱的CI表型。     

Genetic variation of the hawthorn spider mite Amphitetranychus viennensis (Acari: Tetranychidae) in Korea

Amphitetranychus viennensis (Zacher) is a serious economic pest of various fruit trees. Due to its restricted geographic distribution in Asia and Europe, it is an important quarantine species in the North American countries. Despite its significance in agricultural damage and quarantine, the genetic diversity of this species has not been studied in detail. In this study, we determined the nucleotide sequences of mitochondrial cytochrome c oxidase subunit I (COI) gene and internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal DNA in A. viennensis collected from various regions of Korea. Variations in the COI and ITS2 sequences of the Korean samples ranged up to 6.92 and 4.02 %, respectively. A sequence comparison showed that the Korean samples were divided into two groups, one comprising the Geoje and Jinju samples, and the other comprising all samples except for the Geoje/Jinju samples. In most samples, except for the Geoje/Jinju samples, variations in both COI and ITS2 sequences were less than 1.04 and 0.99 %, respectively. However, the variations between two groups were 6.23–6.92 % and 3.02–4.02 %, respectively. In addition, the phylogenic analysis performed with sequences in the GenBank database showed that the samples from Geoje/Jinju, which are located in the southern region of Korea, were most similar to the Japanese samples, but the others were most similar to those of China and Taiwan. Thus, our study suggests that two genetically different groups of A. viennensis exist in Korea.     

Male age and sexual experience affect male mating behavior in the hawthorn spider mite,Amphitetranychus viennensis

As is reported, in species with first-male sperm precedence, male age and previous sexual experience play crucial roles in male mating behavior. In the hawthorn spider mite, Amphitetranychus viennensis Zacher, previous studies showed that only females that copulated for the first time could achieve fertilization. Based on this, the effects of male age and mating history on male mate choice and male mate competition were investigated. It was confirmed that males could distinguish virgins from fertilized females but they were unable to discriminate between virgins and unfertilized females. Interestingly, the copulation duration of males mated with fertilized females was much shorter than that of males mated with virgins or unfertilized females. Additionally, for male mating choice, males of all ages and more experienced males preferred 5-day-old virgin females, whereas only less experienced males preferred 1-day-old virgin females. In male-male competition, 3-day-old males were more competitive and obtained more copulations compared with others. Copula duration was closely related to male age. Though no significant differences were observed in mating competition between virgin and mated males, copula duration of males in first copulation was the longest and gradually shortened in subsequent copulations. In all, this investigation demonstrated that male age and sexual experience affected male mate choice and male-male competition, leading to further insight into the influences of male age and sexual experience on the reproductive fitness of both sexes.

     

延迟交配对山楂叶螨繁殖的影响

为了探索雌螨延迟交配对整个种群的负面效应, 采用叶碟饲养法, 在室内条件下研究了延迟交配对山楂叶螨Tetranychus viennensis Zacher繁殖及种群增长的影响。结果表明: 雌螨延迟交配主要影响寿命、产卵量, 进而影响种群增长率; 随着雌螨交配时间的延迟, 影响的程度逐渐加剧。交配延迟达到或超过7 d, 雌螨的寿命比对照延长20.17%, 产卵量比对照下降26.74%, 但对后代的孵化率、存活率无明显影响。对生命表参数的分析结果表明, 雌螨交配延迟达到或超过7 d, 会导致净生殖率显著下降、平均世代周期历期显著延长, 而内禀增长率则在交配延迟3 d时显著降低。未经交配的雌螨只能营孤雌生殖, 寿命延长了31.14%, 产卵量减少了30.08%。营孤雌生殖的雌螨可以通过与其后代回交而实现两性生殖。结果提示延迟交配会导致山楂叶螨的繁殖力降低。     

Distribution of the spider mite Tetranychus urticae Koch (Acarina,Tetranychidae) over the leaves of different cucumber cultivars

Distribution of spider mites over cucumber leaves is determined by the topical trophic specialization of the pest manifested in preference for the central leaf zone. After artificial infestation of leaves with female mites, the modified aggregated distribution of the pest depended on the number of mites on the leaf, the morpho-physiological state and stage of development of the leaf and the whole plant, and the cucumber cultivar.     

Influence of the spider mite, Tetranychus urticae Koch (Acarina, Tetranychidae) population density on its dynamics on different cucumber cultivars

The dependence of the population dynamics, dispersal behavior, and formation of the migration stage of the spider mite, Tetranychus urticae K. on the population density on cucumber plants differs between cultivars. The optimum spider mite density providing the maximum reproduction may be determined by the cucumber plants cultivar and the morphophysiological state of the plants.     

DNA sequences and cross-breeding experiments in the hawthorn spider mite Amphitetranychus viennensis reveal high genetic differentiation between Japanese and French populations

Sequence variation of the complete second internal transcribed spacer (ITS2, 445 bp) of nuclear ribosomal DNA and part of the mitochondrial cytochrome oxidase I gene (COI, 350 bp) was examined in Amphitetranychus viennensis (Zacher) mites (Acari:Tetranychidae) from four French and four Japanese locations. Sequence analysis consistently revealed the separation of the samples in two major groups: French mites differed from Japanese by 3.8–4.1% of the nucleotide divergence in COI sequences. These two groups also displayed distinct ITS2 consensus sequences (2.1% nucleotide divergence). A few variations, not affecting the diagnostic sites around the consensus sequence, were revealed among cloned copies of the same individual. Reciprocal crosses and backcrosses between one French and two Japanese populations disclosed strong reproductive incompatibility. However, fertile hybrid females were obtained, indicating the conspecificity of the tested mites. Despite the presence of Wolbachia in the French strain, but not in the Japanese ones, our crosses did not display the unidirectional incompatibility typically produced by this microorganism, but rather a bidirectional – although asymmetrical – incompatibility pattern. The post-zygotic incompatibilities in A. viennensis cannot be explained by the presence of Wolbachia but to some extent by mite genome divergence resulting from limited gene exchange between allopatric populations. Experiments of Wolbachia elimination by antibiotic treatment and subsequent crosses with cured strains are still needed to fully understand the reproductive incompatibility patterns in this mite species.     

Photobehavioral classes of the spider mite Tetranychus urticae (Acarina: Tetranychidae)

A shift in photobehavior and geotaxis in the summer adult female spider mite, Tetranychus urticae Koch, results from water stress. The slow reversal of sign from the green minus to the green plus photobehavioral class is the result of this stress. It is postulated that decrease of internal pressure, as a result of water loss, is perceived by a stretch receptor. A rapid decrease in the response to green illumination by the green⁺ class is caused by high ambient relative humidity. It is postulated that a humidity receptor is involved in this rapid change in behavior.

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Zusammenfassung Wassermangel ergibt bei erwachsenen Sommerweibohen der Spinnmilbe Tetranychus urticae Koch eine Verschiebung im Verhalten zum Licht sowie der Geotaxis. Eine langsame Verschiebung von der grün-negativen zur grün-positiven Klasse ist das Ergebnis einer solchen Belastung. Es wird angenommen, daß als Folge von Wasserverlusten eine Abnahme des Binnendruckes durch Streckrezeptoren wahrgenommen wird. Eine rasche Abnahme der Reaktion auf grüne Beleuchtung wird in der grün-positiven Klasse durch hohe relative Luftfeuchtigkeit der Umgebung hervorgerufen. Es wird angenommen, daß an diesem raschen Verhaltenswechsel ein Feuchtigkeitsrezeptor beteiligt ist.

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Contribution from the Massachusetts Agricultural Experiment Station.     

山楂叶螨在苹果不同品种上的生长发育及繁殖

室内试验结果表明 ,山楂叶螨TetrancychusvienensisZacher在苹果不同品种上的生长发育和繁殖有较大的差异。其中在红星上存活率高 ,发育速度快 ,生殖力强 ;而在秦冠上存活率低、发育速度慢、生殖力低。对山楂叶螨种群年结龄构的分析表明 ,卵在种群中所占比例较高 ,而成虫所占比例甚低 ,建议在对其进行防治时选用杀卵力强的药剂     

高温冲击对山楂叶螨的影响

为探索高温冲击对山楂叶螨的影响,在室内采用叶碟饲养的方法,将山楂叶螨不同螨态暴露于33-42℃高温下1-6h,然后在温度(25±1)℃、相对湿度(60±7)%、光周期16h∶8h(L∶D)下测定其寿命、产卵量和孵化率。结果表明,高温冲击对山楂叶螨的影响主要表现在对其产卵量和孵化率的影响,而对成螨的寿命无明显影响;影响的程度取决于高温的强度、持续时间以及处理的螨态。卵经历33-42℃的高温处理1-6h,其孵化率无明显变化,但在随后的发育过程中,幼若螨的发育历期在39℃和42℃6h处理中显著延长,发育至成螨后其产卵量分别增加34.50%和37.41%;幼螨经历39℃和42℃的高温处理6h后发育至成螨时产卵量比对照高出27.02%和35.83%;静止期第二若螨经历39℃和42℃的高温处理,其发育成的雌雄螨的交配和受精能力无明显影响;初羽化雌成螨经历39℃和42℃的高温处理6h后,产卵量不受影响,但卵的孵化率降低了7.01%-11.36%。     

二斑叶螨对不同品种茄子的选择性与适合度

【目的】为明确二斑叶螨Tetranychus urticae Koch对不同品种茄子的选择性与适合度。【方法】通过二斑叶螨对不同品种茄子的田间选择性试验以及在室内不同品种茄子对二斑叶螨种群数量、个体生长发育和繁殖的影响试验,分析了二斑叶螨对9个茄子栽培品种和1个野生茄子品种的寄主选择性,以及在不同品种上的种群动态、发育历期和繁殖力。【结果】二斑叶螨对野生品种蒜芥茄Solanum sisymbriifolium的选择性最差,在该品种上除卵可以正常孵化外其他时期均不能存活。在茄子S.melongena品种间,二斑叶螨对京茄6号和日友长直壮青长茄的选择性最强,分别达到195和183头/株,对布利塔和长竹丝茄的选择性最差,分别为63.5和59.75头/株。接入20对成螨后第28天,紫龙王4号上的数量最多(1 009头/株),京茄6号和嫁接的京茄6号上的数量次之(分别为981和909头/株)。二斑叶螨在京茄6号上的发育历期最短,为9.31 d;在长丰2号上发育历期最长,为11.08 d。京茄6号、京茄黑霸和嫁接的京茄6号上二斑叶螨开始产卵的前5 d内单雌产卵量分别为35.92,33.20和31.34粒/头,是产卵量较多的3个品种,且3个品种之间差异不显著;紫龙王4号、茄砧1号、布利塔和长丰2号上的产卵量较少,分别为18.56,19.24,22.26和23.36粒/头,且4个品种之间差异不显著。【结论】二斑叶螨对紫黑圆茄类的京茄6号的选择性较强、适合度较高,对紫黑长茄布利塔的选择性和适合度为中等,对野生品种蒜芥茄的选择性和适合度表现为最差。     

Development of two spotted spider mite (Acari: Tetranychidae) populations on strawberry and raspberry cultivars

Five strawberry (Fragaria sp.) and five raspberry (Rubus ideaus L.) cultivars were evaluated for resistance to two spotted spider mite (Tetranychus urticae Koch.). Two methods of assessing the development of two spotted mite populations using detached leaves were compared. The number of eggs laid and mites which developed were compared. The strawberry cvs Hapil and Pegasus had significantly greater development of two spotted mite populations than the cvs Rhapsody, Symphony and Elsanta. The raspberry cv. Joan Squires had higher populations of two spotted mite whilst the raspberry cv. Leo the least, when compared with cvs Glen Clova, Glen Moy and Glen Prosen. Differences were observed in oviposition sites and mite distribution when comparing raspberries with strawberries. The method of assessing the populations development of two spotted mite which involved maintaining the cut leaf stem in water may be of potential use for studying population dynamics of both two spotted mite and possible predators over extended periods of time.     

The effect of interspecific mating on sex ratios in the twospotted spider mite and the Banks grass mite (Acarina: Tetranychidae)

Mixed populations of the twospotted spider mite (TSM),Tetranychus urticae (Koch), and the Banks grass mite (BGM),Oligonychus pratensis (Banks), occur on corn and sorghum plants in late summer in the Great Plains. Interspecific matings between these arrhenotokous species occur readily in the laboratory but yield no female offspring. The effect of interspecific mating on female: male sex ratios was measured by examining the F₁ progeny of females that mated with both heterospecific and conspecific males in no-choice situations. TSM females that mated first with BGM males and then with TSM males produced a smaller percentage of female offspring than TSM females that mated only with TSM males (43.1±5.8 and 78.9±2.8% females, respectively). Similarly, BGM females mated with heterospecific males and then with conspecific males produced fewer female offspring than females mated only with BGM males (55.7±5.2 and 77.5±2.5%, respectively). Lower female: male sex ratios were produced also by BGM females that mated with TSM males after first mating with conspecifics (62.4±3.4%). In mixed populations containing males of both species, females also produced lower female: male sex ratios, but these ratios were not as low as expected based on mating propensities and progeny sex ratios observed in no-choice tests. These data suggest that interspecific mating may substantially reduce female fitness in both mite species by reducing the output of female offspring, but in mixed populations this effect is mitigated by unidentified behavioral mechanisms.     

Dispersal of the glasshouse red spider mite Tetranychus urticae Koch (Acarina, Tetranychidae)

Under glass Tetranychus urticae Koch spreads by (a) migration of teneral females to oviposition sites (b) migration of mites from heavily infested plants by falling without the usual silken parachutes normally used by Tetranychid mites and (c) movement over the soil surface in accordance with the plane of polarized light.It is postulated that the effect of this combination of dispersal mechanisms is to restrict mite populations to one portion of a glasshouse from season to season with relatively slow lateral spread from these centres during each growing season.

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Zusammenfassung Bewegung auf der Wirtspflanze ist auf negativ geotaktisches Wandern der jungen Weibchen beschränkt, während Abwanderung nur stattfindet, wenn die Wirtspflanze so sehr zu Schaden gekommen ist, daß an den obersten Teilen der Pflanze keine frischen Blätter mehr vorhanden sind.Experimente haben gezeigt, daß — ungleich anderen Tetranychiden — Milben dieser Art nicht an seidenen Fallschirmen in der Luft treiben können, sondern zwangsläufig von seidenen Fäden zu Boden fallen, die sie als pendelnde Taue an stark befallenen Pflanzen bilden. Am Boden reagieren die Milben auf die Ebene des polarisierten Lichtes.Es wird daraus geschlossen, daß in Gurkenhäusern die Ausbreitung von den Überwinterungs-plätzen oder stark befallenen Pflanzen aus seitwärts nur in beschränktem Ausmaße erfolgt, so daß die Kolonien von Jahr zu Jahr in den gleichen Teilen des Gewächshauses auftreten.

     

Molecular characterization of two novel esterase genes from carmine spider mite,Tetranychus cinnabarinus (Acarina: Tetranychidae)

Abstract Two novel esterase complementary DNAs were identified and cloned from the insecticide-susceptible strain of Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae), which were designated as TCE1 and TCE2, respectively. The cDNA of TCE1 gene contained an open reading frame (ORF) of 1701 bp encoding 567 amino acids, and a predicted molecular weight of 62.75 kDa, the cDNA of TCE2 contained an ORF of 1680 bp encoding 560 amino acids, and a predicted molecular weight of 63.14 kDa. TCE1 and TCE2 were submitted to GenBank, accession number EU130461 and EU130462. The well-conserved sequence motif, GXSXG, used as a signature pattern in the esterase family are present in both TCE1 and TCE2 (GQSAG in TCE1, whereas GESAG in TCE2), indicating that these two genes are predicted to be esterases. Comparison of the deduced amino acid sequence with the published mite esterase sequence coming from Boophilus microplus showed that TCE1 shares 33.98% identity and TCE2 shares 33.46% identity. TCE1 and TCE2 share 46.4% identity. Quantitative real-time polymerase chain reaction revealed that expression level of the TCE2 gene was relatively higher than that of the TCE1 in all instars examined except the protonymph, and the expression level of these two esterase genes in adults of T. cinnabarinus was significantly higher than that in any other instars, respectively. T. cinnabarinus is an important agricultural mite pest and esterases are important in the metabolisms of insects and mites; the genomic information obtained in this study will contribute to esterase molecular biological study on mite pest species.     

不同寄主植物对山楂叶螨生长发育和繁殖的影响

室内采用叶碟饲养的方法研究了苹果、桃、李、樱桃和杏等不同果树对山楂叶螨Tetrancychusvienensis生长发育和繁殖的影响。结果表明,在李树上山楂叶螨的发育历期短、生殖力强、存活率高,rm值大,而在樱桃和杏树上该螨的发育历期长、生殖力弱、存活率低、rm值小。寄主转换试验结果表明,当山楂叶螨由苹果转移至樱桃和杏树时,其生长发育的历期显著延长,rm值大幅度降低;而由苹果转移至桃树和李树时,其生长发育的历期虽也有所延长,但差异不显著,rm值则明显降低。表明山楂叶螨对新寄主的适应因不同寄主而异,在桃和李上经历1代后即可适应,而在杏和樱桃上经历2代后才能适应新的寄主。     

Nucleo-cytoplasmic interactions causing partial female sterility in the spider mite Tetranychus urticae Koch (Acarina: Tetranychidae) II

Non-reciprocal hybrid infertility between the strains ZI and ZII of the spider mite Tetranychus urticae Koch, probably based on an interaction between a chromosomal gene N, and a non-chromosomal factor E, is studied. A hypothesis that N-E interaction causes egg mortality indirectly through the formation of recessive lethal genes, is tested and rejected.     

Genetic affinities between spider mite Tetranychus urticae (Acarina: Tetranychidae) populations in a non-agricultural area

Partial reproductive incompatibility between spider mite populations from adjacent glasshouses is a common phenomenon. It is demonstrated that such a multitude of incompatibilities is not found outdoors between populations collected from ground-ivy (Glechoma hederacea) growing in a dune area on the west coast of the Netherlands.

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Zusammenfassung Eine partielle reproduktive Unverträglichkeit zwischen Spinnmilbenpopulationen benachbarter Glashäuser ist eine häufige Erscheinung. Es wurden Untersuchungen unternommen um abzuklären, ob in einer verhältnismässig ungestörten nichtlandwirtschaftlichen Gegend eine ähnliche Situation existiert. 48 Stämme von Tetranychus urticae wurden auf Gundelrebe, Glechoma hederacea, gesammelt, welche in 5 Lokalitäten einer Dünengegend der holländischen Westküste wuchsen. Zwischen diesen Stämmen wurden Kreuzungen in 89 Kombinationen durchgeführt. Die F₂-Eimortalität lag meist unter 15% und war im Durchschnitt um 9% (Tabelle I). Die Kontrollwerte (Tabelle I, Gruppe III) waren nicht signifikant tiefer. Dies ist in auffälligem Gegensatz mit den Untersuchungen, welche durchgeführt wurden mit Spinnmilbenpopulationen eines Glashauskomplexes, der eine ähnlich grosse Fläche bedeckt (Helle & Pieterse 1965, Overmeer & Van Zon, 1976).

     

不同柑桔品种上桔全爪螨的生长和种群动态差异

通过田间调查、室内盆栽苗接螨、离体叶片饲养等方法,考察了14个柑桔品种上桔全爪螨种群动态,组建了其实验种群生命表,结果表明：该螨在各柑桔品种上的种群密度有明显差异,平均密度以北碚447、台湾晚白柚和垫江白柚上较高,柑新生系最低。雌成螨寿命在台湾晚白柚上最长,垫江白柚次之,柑新生系最短;产卵量以取食台湾晚白柚时最多,垫江白柚、五步红心柚次之,以柑新生系最少;在垫江白柚上的内禀增长率（r_m）最大,沙田柚、台湾晚白柚次之,金弹最小。根据桔全爪螨实验种群的参数判断,金弹和柑新生系属抗螨品种,台湾晚白柚、垫江白柚和北碚447是感螨品种。从品种归类上来看,柚类品种和甜橙中的北碚447感螨程度较高,金柑属的金弹和宽皮柑桔类的柑新生系感螨程度较低。甜橙类与宽皮柑桔类比较,前者感螨程度较高,后者相对较低,但宽皮柑桔类的早津感螨程度相对较高。