青藏公路对高原鼠兔种内遗传分化的影响

研究采用7个微卫星标记分析在青海省西大滩区域,位于青藏公路两侧的4个高原鼠兔（Ochotona curzoniae）种群的遗传变异情况。分别采用软件TFPGA和GENE POP3．4计算各种群间的Nei’s标准遗传距离,基因分化系数（Fst）等参数,并对遗传距离进行UPGMA聚类分析。研究结果表明,公路同侧种群间平均遗传距离和基因分化系数分别为0．0808和0．0541;异侧种群间平均遗传距离和基因分化系数分别为0．1037和0．0705,公路东侧和西侧的两个种群分别聚为一类。青藏公路对分布于公路两侧的高原鼠兔种群间的基因交流产生了一定的阻隔效应,并导致种群间出现了一定程度的遗传分化。     

不同食料植物对棉铃虫生长发育和繁殖的影响

报道了棉花、烟草、番茄和辣椒4种植物对棉铃虫Helicoverpa armigera生长发育和繁殖的影响。棉铃虫成虫喜欢在番茄上产卵,在辣椒上的着卵量最少。初孵幼虫喜选食嫩棉叶,选食辣椒嫩叶的虫数最少。4组幼虫取食嫩叶时的平均相对生长速率都有显著差异,顺序为棉叶组>烟叶组>番茄叶组>辣椒叶组。幼虫存活率以取食棉花时最高,取食番茄时最低。棉花组成虫的产卵量最高,烟草组的产卵量最低。取食棉花的棉铃虫种群增长的速度约为取食番茄时的14倍。6龄幼虫能有效利用和转化棉铃、烟草蒴果、辣椒果实,而对番茄果实的利用和转化效率较低。棉铃虫可分别以这4种植物的不同器官为食完成世代循环。其中,棉花是最适宜的寄主,辣椒和番茄是较不适宜的寄主。     

寄主胁迫下小菜蛾种群的RAPD分析

采用RAPD-PCR技术,研究了取食6种不同十字花科寄主植物第4、9、15代小菜蛾Plutella xylostella(L.)种群的DNA多态性。通过17条引物的重复PCR扩增实验,利用NTsys软件对电泳条带统计分析,构建了遗传距离矩阵和聚类分析图谱。结果表明:取食芥蓝的小菜蛾种群与其它5种寄主种群遗传距离较远(0.6523～0.8246),独立聚为一枝;取食萝卜的小菜蛾种群遗传距离与甘蓝上种群较近(0.3443),聚为一枝,并且与白菜、芥菜和菜心上小菜蛾种群遗传距离较近,逐次聚为一枝,芥蓝、萝卜及甘蓝寄主种群随代次的增多种群分化出现稳定规律性。各寄主种群间遗传距离平均值和范围、多态性条带占总条带数目的比例随代次增多而增大,说明种群分化程度随代次增多而加深。     

海南粗榧(Cephalotaxus mannii Hk.f.) 5个种群遗传多样性及分化研究

采用垂直板型聚丙烯酰胺凝胶电泳测定了海南粗榧5个种群遗传多样性和遗分化程度。结果表明：海南粗榧种群遗传多样性水平较低,多态位点比率P＝0．33,等位基因平均数A＝1．33,平均期望杂合度为He=0．135,观察杂合度为Ho＝0139。种群间遗传分化程度较低,基因分化系数Gst=0.123,种群间遗传一致度和遗传距离的均值分别为0．9719、9．0288。黎母山种群与其它种群分化最大,其原因可能与传粉时盛行的风向有关。     

烟粉虱在烟株上的垂直分布及寄主选择性

烟粉虱是云南省农业生产上的重要害虫之一。通过田间系统调查和室内观察相结合,研究了烟粉虱在烟株上的垂直分布特性和在8种寄主作物上的取食、产卵趋性。（1）烟粉虱在烟株上的垂直分布特征为上部＞中部＞下部,8月中旬为种群高峰期,上、中、下部叶片的成虫密度分别为15．1、10．9、6．7头？片-1;（2）烟粉虱成虫的取食趋性表现为大豆＞南瓜＞甘薯＞番茄＞一品红＞茄子＞甘蓝＞烟草,各处理间差异不显著（P＞0．05）;（3）产卵趋性表现为一品红＞大豆＞南瓜＞甘薯＞番茄＞茄子＞甘蓝＞烟草,一品红与南瓜、甘蓝、茄子、甘薯、番茄、烟草处理间,以及大豆与烟草处理间存在显著差异（P＜0．05）,其他处理间差异不显著（P＞0．05）。在所测定的8种寄主植物中,烟粉虱成虫对烟草的选择性最差,烟区规划烟田种植范围时,应避免与大豆、南瓜、甘薯、番茄等作物间作或距离太近。     

内蒙古中部小驼嗡蜣螂七个种群的遗传多样性

采用RAPD分子标记技术分析了内蒙古中部地区小驼嗡蜣螂（Onthophagus gibbulus）7个种群的遗传多样性及遗传分化。16条引物共检测到363条带,总多态位点比率为100％,Nei基因多样度为0．280,总的Shannon信息指数为0．433,结果表明,小驼嗡蜣螂种群遗传多样性丰富。在总的遗传变异中,12．57％的变异存在于种群间,87．43％的变异存在于种群内,种群间的遗传分化程度较低,种群间遗传分化系数（Gst）在0．074～0．203,基因流（Nm）在4．569～9．791,表明种群间存在广泛的基因交流。在本研究涉及的地理范围内,小驼嗡蜣螂种群的遗传距离与地理距离不相关,说明小驼嗡蜣螂种群间的分化与其生境的异质性有关。     

中国东北地区亚洲玉米螟遗传多样性及寄主专化性分析

【目的】为了明确中国东北地区亚洲玉米螟Ostrinia furnacalis不同地理种群、不同田间寄主种群间的遗传分化程度和基因流水平,了解不同种群间是否产生寄主专化性和遗传结构的差异。【方法】采用双向测序法测定了采自中国东北3种主要寄主植物(玉米Zea mays、高粱Sorghum bicolor和谷子Setaria italica)上的23个地理种群400头亚洲玉米螟个体的线粒体细胞色素氧化酶亚基I (COI)基因的1 034 bp序列;利用DnaSP 5. 0和Arlequin3. 5. 1. 2等软件对亚洲玉米螟不同寄主种群以及不同地理种群间的遗传多样性、基因流水平、系统进化发育和分子变异进行分析。【结果】共获得400条长度为1 034 bp的亚洲玉米螟线粒体COI基因序列,包含60个单倍型。亚洲玉米螟总群体的单倍型多样度(Hd)为0. 793±0. 01,不同地理种群间的单倍型多样度范围在0~0. 916±0. 041之间。总基因交流水平较高(Nm=2. 67),总的群体Fst为0. 1579,不同地理种群的Fst范围在-0. 046~0. 627之间。总种群的Tajima’s D为-1. 73602,检验结果不显著,说明中国东北地区亚洲玉米螟未曾在近期经历种群扩张,群体大小稳定。AMOVA分子变异分析结果表明,不同地理种群间的遗传分化较大(Fst=0. 16236,P 0. 0001),83. 76%遗传变异主要来自种群内部,而种群间的遗传变异仅为16. 24%,不同寄主种群间的遗传分化(Fct=0. 01568,P 0. 05)很小,遗传变异仅占1. 57%,说明亚洲玉米螟的遗传分化主要来自种群内部,而非其地理种群间或寄主种群间。各寄主种群的单倍型在系统发育树上和中介网络图上散布在不同种群中,缺乏明显的地理分布和寄主分布格局。【结论】亚洲玉米螟较强的迁飞能力(或随气流进行远距离传播),使各种群间的基因交流未受到地理距离的影响,遗传距离与地理距离之间没有显著相关性。虽其寄主范围较广,但取食不同寄主植物的亚洲玉米螟种群间基因交流频繁,以玉米、高粱和谷子为寄主的种群尚未产生寄主专化性和种群遗传结构的差异。     

寄主植物轮换饲养和次生代谢物交叉涂布对棉铃虫取食的影响

食物混合通常对多食性昆虫的生长表现有积极的影响,然而此前的研究对象主要是成虫期和幼虫期迁移能力较强的种类。某些鳞翅目种类尽管是多食性的,但其幼虫个体因时空隔离的原因,并无机会自由选择食料寄主。采用寄主叶片轮换饲养和次生代谢物交叉涂布两种方法研究了多食性棉铃虫幼虫的取食行为,供试寄主植物包括烟草、辣椒、番茄和棉花,次生代谢物采用自然浓度进行交叉涂布。结果表明,食物混合并没有造成幼虫总体摄食量的显著增加。其中,烟草和水合烟碱能显著抑制棉铃虫对其他寄主叶碟的取食,而辣椒及(E)-辣椒素对其他寄主叶碟的被食量均无影响。番茄叶片轮换饲养不影响棉铃虫对与其轮换的其他寄主叶片的被食量,但α-番茄苷涂布在辣椒和棉花叶碟上则对棉铃虫有显著拒食作用。棉花-烟草轮换饲养组中的烟草被食量显著大于烟草非轮换组中的烟草被食量,但(+)-棉酚涂布处理却能显著抑制棉铃虫对烟草的摄食。两种生物测定方法均未发现棉花与辣椒存在显著性相互影响。总之,棉铃虫可能是以耐受式的对策适应寄主植物次生代谢物的,符合相称性形态构成假说,即扩散能力较差的鳞翅目幼虫个体并不需要进化出同时应对来自两种或两种以上的寄主植物次生代谢物的适应机制。     

短柄袍种群遗传多样性的ISSR分析

利用ISSR分子标记方法对分布在浙江省境内的7个短柄袍种群的遗传多样性和遗传分化进行了分析。从100个引物中筛选出12个用于正式扩增的ISSR引物,在7个种群140个个体中共检测到132个位点,其中多态位点118个,多态位点百分率（P）为89．39％,各种群P平均为58．87％。短柄袍总的Shannon信息指数（I）为0．4933、Nei指数（h）为0．3347,各种群,平均为0．3362、h平均为0．2291。P、I,h均显示云峰种群最高,天台山种群最低。AMOVA分子差异分析表明,67．97％的变异存在于种群内,32．03％的变异存在于种群间,种群间的基因分化系数（GST）为0．3154。短柄袍种群间的基因流为（Nm）为1．0853。7个种群的平均遗传距离为0．1739。利用UPGMA法对7个种群进行聚类,结果显示天台山和雪窦山种群聚成一类,其它5个种群聚成另一类。     

不同地区棉铃虫种群DNA多态性的RAPD分析

通过对棉铃虫Helicoverpa armigera(Hubner)17个地理种群DNA多态性进行了RAPD分析,结果表明：棉铃虫可以分为四大类群,三亚(SY)、莎车(SC)和哈密(HM)种群各为独立的一类,与内地种群有明显的差异,其中三亚种群差异最大;第四类包含14个地理种群,它们之间相对分化较小,基因相似程度较高,特别是黄河流域和辽河流域南部的种群间遗传距离最小,无基因交流障碍。单个个体的RAPD分析表明,这些种群间的某些个体相互交错,进一步说明这些种群间可能存在着广泛的基因交流。最后还讨论了形成棉铃虫遗传多态性的主要原因,     

Genetic differentiation of Helicoverpa armigera (Hübner) and H. assulta (Guenée) (Lepidoptera: Noctuidae) based on AFLP markers

Abstract Here we use amplified fragment length polymorphism (AFLP) to assess genetic differentiation of Helicoverpa armigera and H. assulta . The results indicated that both species-specific fingerprints and cluster analysis showed the ability of AFLP technique to discriminate the two sibling species; among a total 1963 AFLP markers amplified from nine primer combinations: 777 (39.6%) were H. armigera -specific, 602 (30.7%) were H. assulta -specific, and 584 (29.7%) were common bands. The mean number of H. armigera -specific bands was significantly more than that of H. assulta -specific bands for nine primer combinations ( P < 0.05); the intraspecific distance of H. armigera and H. assulta was 0.123 0 and 0.110 7 respectively, and the interspecific distance was 0.178 3. In addition, the percentage of polymorphic loci and estimated average heterozygosity were used to estimate genetic diversity of the two species. This study therefore demonstrates that AFLP analysis is a sensitive and reliable technique to study genetic differentiation and genetic relationships between species and provides sufficient molecular markers for future linkage map construction, location and eventual cloning of genes involved in traits differentiation.     

Genetic basis of sex pheromone blend difference between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

The two closely related moth species, Helicoverpa armigera and H. assulta, are sympatric in China. Both species use a mixture of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as their sex pheromones but in widely different ratios. Hybridization and backcrossing experiments between H. armigera and H. assulta were conducted and sex pheromone compositions of the parent species, their F(1) hybrids and backcrosses were compared to study the genetic basis of the production of their sex pheromone blend composition. Results show that the difference in sex pheromone blend ratios of these Helicoverpa species is mainly controlled by an autosomal locus with two alleles, with the allele from H. armigera being almost completely dominant over that derived from H. assulta.     

Using COI gene sequence to barcode two morphologically alike species: the cotton bollworm and the oriental tobacco budworm (Lepidoptera: Noctuidae)

Due to limited morphological difference, the two closely related sister species, the cotton bollworm, Helicoverpa armigera (Hübner) and the oriental tobacco budworm, H. assulta (Guenée) (Lepidoptera: Noctuidae), are very difficult to distinguish, especially at the larvae stage. Recently, DNA sequence has been widely used as a bio-barcode for species identification. In this study, we attempted to distinguish H. armigera and H. assulta using the mitochondrial cytochrome C oxidase subunit I gene (COI) gene sequence as the barcode. We determined a 658 bp segment of the COI gene for 28 individuals of H. armigera, 8 individuals of H. assulta, and 10 individuals of Mamestra brassicae (as the outgroup) in Yunnan Province, southwest of P. R. China, together with one H. assulta and two H. armigera reported sequences from GenBank. Twenty-three haplotypes were identified in all 49 samples. As expected, network analysis of the haplotypes of the three species presented a clustering pattern consistent with the respective species status. Haplotypes of the same species differed from each other by no more than three nucleotide substitutions. However, each haplotype of H. armigera differed from that of H. assulta by at least 22 nucleotide substitutions. Both species differed from M. brassicae by more than 50 nucleotide substitutions. 17 unique diagnostic nucleotides were also used to discriminate the two species. The finding of large COI sequence differences between H. armigera and H. assulta suggested that it could be used to distinguish the two morphologically alike species and be employed for quick species identification during pest control.     

植物次生物质对烟青虫和棉铃虫食物利用及中肠解毒酶活性的影响

用分别添加0-5%(干重比)棉酚、烟碱、番茄苷和辣椒素4种植物次生物质的人工饲料饲养烟青虫Helicoverpa assulta和棉铃虫H. armigera 5龄幼虫48 h,测定这些次生物质对烟青虫和棉铃虫的营养效应和中肠谷胱甘肽S-转移酶（GST）及羧酸酯酶（CarE）活性的影响。结果表明：在实验浓度下,棉酚可显著降低烟青虫的相对消化率,但对棉铃虫却有助食作用;番茄苷抑制烟青虫的取食和生长,对其近似消化率和食物利用率也有显著的抑制作用,但食物转化率有明显升高,对棉铃虫的各营养指标无显著影响;烟碱对烟青虫和棉铃虫的相对生长率均无影响;辣椒素使烟青虫的取食量有大幅度的提高,对棉铃虫的取食量无影响,但引起其相对消化率的提高。由此可见,棉铃虫对4种次生物质有普遍的适应性,而烟青虫只对寄主植物所含的烟碱和辣椒素有较好的适应性。烟青虫和棉铃虫幼虫中肠CarE活性不受4种次生物质的影响,烟碱和辣椒素对烟青虫GST有显著的诱导作用,番茄苷对烟青虫GST活性则有抑制作用,4种次生物质对棉铃虫GST均无显著影响。     

烟草挥发物对2近缘种夜蛾产卵行为的影响及其成分分析

寡食性烟夜蛾Helicoverpa assulta (Guenée)和广食性棉铃虫H.armigera (Hübner)是铃夜蛾属2近缘种,烟草是其共同寄主.室内实验测定了1个普通烟草品种和4个黄花烟草品种叶片挥发物对二者电生理和行为反应的影响.结果表明,烟夜蛾处女雌蛾和交配雌蛾对4个黄花烟草品种叶片挥发物的EAG反应均显著高于普通烟草,而棉铃虫对普通烟草叶片挥发物的反应显著高于黄花烟草;二者的行为反应与EAG测试结果相似,黄花烟草叶片挥发物对烟夜蛾有较强的引诱作用,棉铃虫对普通烟草叶片挥发物有较强趋性;两种夜蛾雄蛾对这些挥发物的EAG和行为反应均没有雌蛾强烈,性别差异显著;GC-MS分析表明,与K326相比,马合烟叶片挥发物中尼古丁的相对含量高(76.91%),绿叶气味种类多但芳香族化合物种类少,挥发物种类和含量的不同是否与两种夜蛾产卵趋性差异相关,有待进一步研究.     

番茄是烟青虫的寄主植物吗？

长期以来,国内有关文献一直将番茄列为烟青虫Helicoverpa assulta的寄主植物,但田间调查结果往往与此矛盾,本研究的目的是阐明番茄是否为烟青虫的寄主植物。室内试验表明,虽然烟青虫成虫在盆栽番茄植株上产卵较多,但无论是用番茄离体嫩叶还是用盆栽植株饲养,初孵幼虫绝大部分在1龄死亡,平均存活时间很短,不会对番茄造成有经济意义的危害;即使用番茄青果饲养的3龄幼虫也不能活到6龄。根据人工饲料饲养结果估测,番茄苷对初孵幼虫的致死中浓度LC₅₀为0.0744%,叶和青果中报道的番茄苷含量已接近或超过此水平,这是幼虫不能存活的主要原因之一。田间调查也表明,烟青虫并不危害番茄。因此,番茄不是烟青虫的寄主植物。文献中的记载很可能是将棉铃虫误判为烟青虫。     

Novel polymorphic microsatellite markers developed in the cotton bollworm Helicoverpa armigera （Lepidoptera：Noctuidae）

A novel set of five polymorphic di- or trinucleofide microsatellite loci suitable for population genetic study were developed from an enriched genomic library for the pest insect cotton bollworm, Helicoverpa armigera, and cross-amplifiability of these and other published loci was tested in a closely related species, the tobacco budworm, H.assulta. The expected heterozygosity at these loci ranges from 0.62 to 0.91 in the cotton bollworm. The observed allele numbers varies from 4 to 12 in the limited number of individuals tested. Although a large proportion of cloned microsatellite sequences are present in multi-copy in the cotton bollworm genome, the overwhelming majority of the finalized polymorphic diallelic loci are tri-nucleotide microsatellites - an unexpected outcome, which should facilitate subsequent genotyping analysis.     

Mechanisms of premating isolation between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

Helicoverpa armigera and Helicoverpa assulta are sympatric sibling species, and in the laboratory they can interbreed and produce viable offspring. To assess the contributions of temporal barriers and sexual barriers to premating isolation, we investigated both the temporal rhythms of calling behavior and pheromone titers of H. armigera and H. assulta females and the behavioral responses of males to conspecific and heterospecific calling females in a wind tunnel. Both H. armigera and H. assulta females called throughout the scotophase, and there was more calling during the second half of the scotophase than during the first half. Maximal pheromone titer and maximal calling activity in H. armigera synchronously occurred at the sixth hour into the scotophase, whereas, in H. assulta, the maximal pheromone titer occurred 2 h before the peak of calling. Pheromone blend ratios of the two species were opposite and, within each species, changes in the ratio within the scotophase and at different ages were relatively small. Males of both H. armigera and H. assulta responded strongly to their conspecific calling females in the wind tunnel and completed the whole courtship sequence. In contrast, they did not land and had no copulation attempts in response to heterospecific calling females. These results show that the two species do not have obvious temporal differences in calling behavior and pheromone production, and the specificity of sex pheromone blend emitted by females plays a key role in their premating isolation. In addition, we summarized the potential isolation mechanisms of H. armigera and H. assulta.     

Metabolic detoxification of capsaicin by UDP-glycosyltransferase in three Helicoverpa species

Capsaicin β-glucoside was isolated from the feces of Helicoverpa armigera, Helicoverpa assulta, and Helicoverpa zea that fed on capsaicin-supplemented artificial diet. The chemical structure was identified by NMR spectroscopic analysis as well as by enzymatic hydrolysis. The excretion rates of the glucoside were different among the three species; those in the two generalists, H. armigera and H. zea, were higher than in a specialist, H. assulta. UDP-glycosyltransferases (UGT) enzyme activities measured from the whole larval homogenate of the three species with capsaicin and UDP-glucose as substrates were also higher in the two generalists. Compared among five different larval tissues (labial glands, testes from male larvae, midgut, the Malpighian tubules (MT), and fat body) from the three species, the formation of the capsaicin glucoside by one or more UGT is high in the fat body of all the three species as expected, as well as in H. assulta MT. Optimization of the enzyme assay method is also described in detail. Although the lower excretion rate of the unaltered capsaicin in H. assulta indicates higher metabolic capacity toward capsacin than in the other two generalists, the glucosylation per se seems to be insufficient to explain the decrease in capsaicin in the specialist, suggesting that H. assulta might have another important mechanism to deal with capsaicin more specifically.     

Hybridization between Helicoverpa armigera and Helicoverpa assulta (Lepidoptera: Noctuidae): development and morphological characterization of F1 hybrids

Reciprocal hybridizations between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) were studied. The cross between females of H. armigera and males of H. assulta yielded only fertile males and sterile individuals lacking an aedeagus, valva or ostium bursae. A total of 492 larvae of the F1 generation were obtained and 374 of these completed larval development and pupated. Only 203 pupae were morphologically normal males, the remaining 171 pupae were malformed. Larvae and pupae that gave rise to morphologically abnormal adults exhibited longer development times. Sterility was not only associated with malformed external sex organs, but also a range of abnormalities of the internal reproductive system: (i) loss of internal reproductive organs, (ii) with one to three copies of an undeveloped bursa copulatrix; or (iii) with one or two undeveloped testes. Normal male hybrid adults showed higher flight activity in comparison with males of both species. In contrast, the cross between females of H. assulta and males of H. armigera yielded morphologically normal offspring (80 males and 83 females). The interaction of the Z-chromosome from H. assulta with autosomes from H. armigera might result in morphological abnormalities found in hybrids and backcrosses, and maternal-zygotic incompatibilities might contribute to sex bias attributed to hybrid inviability.