不同专化型棉蚜对寄主的选择及其机制初探

【目的】研究棉花型棉蚜和黄瓜型棉蚜依靠味觉的寄主选择行为及其机制。【方法】采用培养皿选择法探究2种专化型棉蚜的寄主选择行为;采用气相色谱-飞行时间质谱联用仪(GC-TOFMS)对棉花、黄瓜及西葫芦苗期叶片的次生化合物组分进行测定,并筛选其差异次生化合物。【结果】行为选择结果显示:棉花型棉蚜和黄瓜型棉蚜显著性地选择其原生寄主棉花和黄瓜,2种专化型棉蚜对西葫芦的选择无显著差异。次生化合物测定结果显示:棉花、黄瓜及西葫芦苗期叶片中次生化合物种类及含量存在较大差异。其中,棉花叶片中的琥珀酸和腐胺的相对含量分别为0.8006和0.1960,黄瓜叶片中对应的含量分别为0.2409和0.4401。【结论】棉蚜对寄主的选择经历了初始的嗅觉选择,完成了味觉的识别,能够反映出寄主次生化合物对棉蚜寄主选择的影响,推测次生化合物种类及含量的差异可能影响不同专化型棉蚜的寄主选择。     

B型烟粉虱触角感受器的超微结构及对寄主植物气味的嗅觉行为反应

利用扫描电镜和透射电镜分别观测了烟粉虱触角感受器的分布、形态和结构。扫描电镜观察结果表明,烟粉虱触角由柄节、梗节和1～5节鞭节组成,绝大部分触角感受器分布在触角的背面、腹面和外侧面。雌、雄蛾触角上均存在5种感器,即微毛感器、锥形感器、刚毛感器、钟形感器和腔锥感器,各种感器在雌、雄蛾触角上的分布和数量没有明显的区别。除了微毛感器和刚毛感器的数量较多外,腔锥感器、锥形感器和钟形感器的数量均较少,分别为6、4和1个。透射电镜观察结果表明,烟粉虱触角上起嗅觉作用的锥形感器和腔锥感器均由表皮壁、鞘细胞和感觉神经元等结构组成。利用"Y型"嗅觉仪测定了烟粉虱雌虫对苘麻、棉花、烟草、黄瓜和甘蓝5种寄主植物气味的行为反应,结果显示,约30%的烟粉虱个体对气味源无反应,50%以上的个体对寄主植物具有显著的行为反应,对寄主植物的选择率差异显著,从大到小顺序为:黄瓜>苘麻>棉花>烟草>甘蓝。     

低温贮存被寄生的烟粉虱伪蛹对丽蚜小蜂种群品质的影响

研究了低温贮存被丽蚜小蜂寄生的B型烟粉虱褐色伪蛹对丽蚜小蜂种群品质的影响。1～6日龄褐蛹于11℃贮存10d的结果表明,3日龄褐蛹中羽化的成蜂寿命、产卵量和刺吸量均优于其他日龄;在11℃下贮存10、20、30d后,上述生物学指标和种群参数均随贮存天数增加而明显降低,其中以10d的净生殖率、内禀增长率和周限增长率较未贮存的差异小。     

Comparative Morphology and Morphometry of Six Biotypes of Bemisia tabaci （Hemiptera： Aleyrodidae） from China

Morphology and morphometry of six biotypes(B,Q,Cv,ZHJ-1,ZHJ-2 and ZHJ-3) of Bemisia tabaci(Gennadius) from China on cotton plants were studied by using microscopes.Nymphal body sizes and characters were measured and observed,especially on the 4th instar(pupal case),including the vasiform orifice,operculum,lingula,length and thickness of anterior and posterior wax margins,width of thoracic tracheal combs.Adult characters of both sexes were investigated including the body size,compound eyes,antennal segments,vasiform orifice,hind tarsi and genitals.The results indicated that differences of some morphological characters or morphometrics were significant among the six biotypes of B.tabaci in China:(1) Pupal sizes of the exotic biotypes(B and Q) were significantly larger than the indigenous biotypes with the following order as B>Q>ZHJ-1>Cv>ZHJ-3>ZHJ-2;(2) for both male and female adults,sizes of all characters investigated in the invading biotypes(B and Q),especially B,were much larger than those of the indigenous ones.     

Comparative Analysis of Population Genetic Structure in Bemisia tabaci （Gennadius） Biotypes B and Q Based on ISSR Marker

Bemisia tabaci （Gennadius） biotypes B and Q are two invasive biotypes in the species complex. The comparison of the population genetic structure of the two biotypes is of significance to show their invasive mechanism and to their control. The intersimple sequence repeats （ISSR） marker was used to analyze the 16 B-biotype populations and 4 Q-biotype populations worldwide with a Trialeurodes vaporariorum population in Shanxi Province, China, and a B. tabaci non-B/Qbiotype population in Zhejiang Province, China, was used as control populations. The analysis of genetic diversity showed that the diversity indexes of biotype Q including Nei＇s gene diversity index, Shannon informative index, and the percentage of polymorphic loci were higher than those of biotype B. The high genetic diversity of biotype Q might provide the genetic basis for the excellent ecological adaptation. Cluster analysis suggested that the ISSR could not be used in the phylogenetic analysis though it could easily distinguish the biotypes of B. tabaci. The difference of the population genetic structure between the biotype B and the biotype Q exists based on the ISSR marker. Meanwhile, the results suggested that the molecular marker has its limitation in the phylogenetic analysis among the biotypes of B. tabaci.     

少花龙葵和三叶鬼针草对甲磺隆抗性的初步研究

 在施用甲磺隆的抗性观察圃里,跟踪调查杂草的抗性生物型,采集表现抗性的杂草——少花龙葵和三叶鬼针草种子,用生物测定和生化分析方法,进行其抗性水平测定。结果表明,连续2年4次施用甲磺隆的少花龙葵和三叶鬼针草,只有少花龙葵表现抗性（抗性因数为2.19,等浓度防效降低29%,敏感性比为1.58,乙酰乳酸合酶的活性比为1.61）。 三叶鬼针草的抗性差异不明显。     

长绒棉区棉花枯萎病菌生理Ⅱ,Ⅲ型监测

1997～ 1 999年 ,从长绒棉区采集 1 80个病株 ,分离获得 84个棉花枯萎病菌菌系 ,选出具有代表性的 1 9个菌株作 , 型鉴定。结果表明 ,供试 1 9个菌系均高度侵染海岛棉 ,高度或轻度侵染陆地棉 ,不侵染中棉 ,均属于生理 型 7号生理小种 ,尚未发现生理 型菌系。根据在 6个鉴别寄主上的致病性反应 ,可将长绒棉区供试菌系划分为强、中、弱 3种类型 ,主要为弱致病型 ,占供试菌系的 47.4%。大分生孢子大小为 ( 1 3.7～ 2 3.6) μm× ( 2 .7～5.4)μm,多为马特型 ,菌丝白色 ,菌落底部紫色或浅紫色 ,部分菌系易产生粘分生孢子团     

寄主型和迁飞型棉蚜在线粒体DNA COⅠ基因序列上的分化

为了探明同域棉蚜(Aphis gossypii Glover)种群的生态分化与进化程度,检测了室内长期筛选所得的迁飞型、滞留型、棉花型和瓜型棉蚜品系,以及在南京田间采集的棉花和黄瓜上的棉蚜,共84个样本的线粒体DNA COⅠ基因的部分序列。结果表明:南京地区寄主型和迁飞型棉蚜种群的COⅠ序列同源性很高,为99.8%～100%。在各样本的569 bp大小序列中检测到3个突变位点,共形成4种单倍型(H1～H4),其中2个突变发生在迁飞型中,另1个发生在滞留型中,而棉花型和瓜型棉蚜中没有检测到突变,各品系棉蚜还共享着同一单倍型H4。迁飞型棉蚜的单倍型多样性(h)最高,为0.68～0.75,滞留型为0～0.18,而棉花型和瓜型无多样性。各种群内核苷酸多样性(π)都极低。UPGMA聚类分析表明,迁飞型与其他各品系间的遗传距离相对较远。系统进化树显示,棉蚜种群正向着3个支系分化:支系一为COⅠ没有变异的棉花型、瓜型、滞留型和迁飞型个体所组成,数量占绝对优势;支系二和支系三仅由迁飞型组成,其COⅠ序列均发生了变异。迁飞型品系中存在突变位点的单倍型H3和没发生突变的H4,在平均寿命、净增殖率与内禀增长率上均没有显著差异,COⅠ序列在该位点上的变异还不足以影响迁飞型棉蚜的生态适合度。     

Q型烟粉虱对20个茄子品种的选择性

为明确茄子不同品种对Q型烟粉虱抗性水平的差异,在室内条件下即温度为（26±1）℃、相对湿度60%~80%、光周期L∥D= 14 h∥10 h,研究了Q型烟粉虱对不同品种茄子的选择性及不同品种对其生长发育和存活率的影响。结果表明,茄子品种对Q型烟粉虱成虫选择性、产卵趋性及卵成虫的发育历期、存活率影响显著。在供试的20个茄子品种中,Q型烟粉虱成虫的选择性和产卵趋性均以‘增丰巨茄’、‘引茄1号’、‘原种紫长茄’最强,‘淄博长茄’、‘海南野茄’、‘紫罐茄王’最弱。卵成虫的发育历期以‘海南野茄’和‘阳春三月茄’上较长,显著长于‘紫红长茄’、‘快圆茄’、‘原种紫长茄’。卵成虫存活率以‘海南野茄’、‘原种紫长茄’、‘紫罐茄王’较低,显著低于‘增丰巨茄’、‘三月茄’、‘引茄一号’、‘特早紫圆茄’。综合分析,从20个茄子品种中筛选出对Q型烟粉虱存在抗性差异的品种为：‘海南野茄’、‘淄博长茄’、‘紫罐茄王’、‘阳春三月茄’为抗性品种,其中‘海南野茄’抗性最强,‘增丰巨茄’、‘引茄一号’、‘原种紫长茄’、‘紫红长茄’、‘快圆茄’、‘三月茄’、‘特早紫圆茄’为敏感品种,其中‘增丰巨茄’敏感性最强。     

Attract-and-kill strategy. Laboratory studies on hatched larvae of Culex pipiens

The attract‐and‐kill strategy is a new pest management technique that presupposes the intelligent combination of an attracting agent (e.g. pheromone) and a killing agent (e.g. insecticide). In the present study, the potential combination of the microencapsulated synthetic oviposition pheromone 6‐acetoxy‐5‐hexadecanolide with an insecticide has been tested. Initially, polyurea microcapsules containing 6‐acetoxy‐5‐hexadecanolide, the synthetic mixture of diastereomers of the oviposition pheromone of the mosquito species Culex quinquefasciatus Say (Diptera: Culicidae), were studied. Laboratory bioassays were performed to confirm the bioactivity of the microencapsulated pheromone on the oviposition activity of Culex pipiens L. biotype molestus Førskal (Diptera: Culicidae) with the aim of determining the optimum dose for oviposition response. Its effect was dose dependent, revealing an optimum dose of 300 mg of dried microcapsules. Attractancy over time was also studied. The microencapsulated pheromone was found to be sufficiently attractive to gravid female mosquitoes for a period of 40 days. Finally, the combination of the synthetic pheromone with the control agent temephos showed both an acceptable oviposition activity and sufficient larvicidal effect. Copyright © 2007 Society of Chemical Industry