淡足侧沟茧蜂寄生对甜菜夜蛾幼虫血淋巴总糖、蛋白质及虫体脂质含量的影响

为探讨淡足侧沟茧蜂Microplitis pallidipes Szepligeti调控寄主的生理机制,测定了淡足侧沟茧蜂寄生后,甜菜夜蛾Spodoptera exigua(Hübner)幼虫血淋巴总糖、蛋白质及虫体脂类含量的变化。研究结果表明,寄生后连续5 d的观察时间内,甜菜夜蛾幼虫血淋巴总糖含量从寄生后第1天开始就高于未寄生寄主幼虫,且在寄生后第2至5天达到显著水平;除寄生后第3天外,被寄生寄主幼虫血淋巴总蛋白质含量始终低于未寄生幼虫,且在寄生后第1、4、5天达到显著水平;甜菜夜蛾被寄生后,虫体脂质含量始终高于未寄生幼虫,且从寄生后第2天开始达到显著水平。本研究揭示,淡足侧沟茧蜂寄生刺激了寄主甜菜夜蛾幼虫血淋巴总糖合成,但抑制了其蛋白质合成,同时也刺激了甜菜夜蛾虫体脂质合成。     

淡足侧沟茧蜂寄生对甜菜夜蛾幼虫血淋巴保护酶和免疫酶的影响

[目的]为探讨淡足侧沟茧蜂Microplitis pallidipes Szepligeti调控寄主甜菜夜蛾Spodoptera exigua(H(u|¨)bner)的生理机制。[方法]测定了淡足侧沟茧蜂寄生甜菜夜蛾后,寄主幼虫血淋巴中保护酶(SOD、CAT及POD)和免疫酶(PO和LSZ)活性的变化。[结果]寄生后连续5 d观察时间内,从寄生后第1天开始,寄主幼虫血淋巴中SOD活性就高于未寄生幼虫(对照),且在寄生后第4~5天达到显著水平;被寄生幼虫血淋巴中CAT活性始终高于对照幼虫,且在寄生后第1、第4~5天达到显著水平;同样,甜菜夜蛾被寄生后,其血淋巴中POD活性明显高于对照幼虫,且在寄生后第1~2、第5天达显著水平;寄生后第1天,寄生与对照组酚氧化酶活性差异不显著,但寄生后第2~5天均达到显著水平;较对照组,寄生后第1~2天,被寄生幼虫溶菌酶活性增加但无显著差异,而寄生后3~4d溶菌酶活性显著降低。[结论]本研究揭示,淡足侧沟茧蜂寄生刺激了甜菜夜蛾幼虫体内的应激反应,诱导寄主体内SOD、CAT和POD活性明显上升,阻止寄生蜂成功寄生;同时,寄生蜂寄生诱导了寄主免疫酶(PO、LSZ)活性的变化,免疫酶活性的变化是寄主免疫系统对寄生蜂寄生的一种应急免疫反应。     

斜纹夜蛾取食四种植物对马尼拉侧沟茧蜂发育和繁殖的影响

研究斜纹夜蛾Spodoptera litura幼虫取食4种植物后对马尼拉侧沟茧蜂Microplitis manilae生长发育和繁殖的影响,为利用该蜂开展斜纹夜蛾的生物防治提供理论依据。在人工气候箱内(26℃±1℃、RH 65%±5%、L∶D=12∶12)研究了斜纹夜蛾取食豇豆Vigna unguiculata、芋艿Colocasia esculenta、烟草Nicotiana tabacum和芥蓝Brassica alboglabra 4种植物对马尼拉侧沟茧蜂的生长发育和繁殖的影响。结果表明:马尼拉侧沟茧蜂寄生取食豇豆的夜蛾幼虫,其幼虫期最短,化蛹率、羽化率和累计存活率最高,性比最低,寿命最长;寄生取食烟草的夜蛾幼虫,其幼虫期最长,化蛹率、羽化率和累计存活率最低,蛹重最轻,蛹期最长;从取食芥蓝的斜纹夜蛾幼虫体内育出的雌蜂产卵量最高,但成蜂寿命最短;斜纹夜蛾取食4种植物对雌蜂个体大小无显著影响,但取食烟草的夜蛾幼虫体内育出的雄蜂个体最小。马尼拉侧沟茧蜂寄生取食不同植物的斜纹夜蛾幼虫,马尼拉侧沟茧蜂的发育和繁殖存在显著差异。     

淡足侧沟茧蜂寄生对草地贪夜蛾幼虫血淋巴黑化反应及酚氧化酶的影响

【目的】明确淡足侧沟茧蜂Microplitis pallidipes寄生对草地贪夜蛾Spodoptera frugiperda血淋巴黑化率、酚氧化酶原（Prophenoloxidase,PPO）基因表达量和酚氧化酶（Phenoloxidase,PO）活性的影响,为更有效的利用淡足侧沟茧蜂防控草地贪夜蛾提供理论依据。【方法】通过室内寄生实验确定草地贪夜蛾被淡足侧沟茧蜂寄生的最佳龄期;通过RT-qPCR分析草地贪夜蛾两个PPO基因（SfPPO1和SfPPO2）的时空表达谱;通过薄膜法统计草地贪夜蛾被寄生后的血淋巴黑化率;采用吸光光度法测定草地贪夜蛾被寄生后的血淋巴PO活性;采用RT-qPCR测定草地贪夜蛾被寄生后血淋巴SfPPO1和SfPPO2的相对基因表达量。【结果】草地贪夜蛾被淡足侧沟茧蜂寄生的最佳龄期为3龄幼虫,SfPPO1和SfPPO2均在卵块和4龄幼虫中基因表达量较高,且主要在幼虫血淋巴中表达。草地贪夜蛾被寄生后12、24、48和72 h的血淋巴黑化率显著低于未寄生组（P<0.05）,SfPPO1和SfPPO2的相对基因表达量和PO活性也低于未寄生组。相关关系分析表明,SfPPO1的相对基因表达量与SfPPO2的表达量呈现线性关系（R2=0.9124）,PO活性与两个PPO基因相对表达量之间、黑化率与PO活性和PPO基因相对表达量之间均呈现正相关。【结论】淡足侧沟茧蜂寄生会抑制草地贪夜蛾血淋巴的黑化率,下调血淋巴中酚氧化酶原基因的表达量和PO活性,且PO活性、PPO基因相对表达量及血淋巴黑化率3个指标之中,两两之间均呈现正相关性。     

核型多角体病毒与侧沟茧蜂对斜纹夜蛾幼虫的协同作用

研究了斜纹夜蛾幼虫体内的斜纹夜蛾侧沟茧蜂存活率、发育历期、寄主感染病毒时间、病毒浓度之间的关系,并测定了斜纹夜蛾侧沟茧蜂的传毒效率．结果表明,病毒对寄主体内寄生蜂历期无明显影响,寄生在幼虫体内的寄生蜂能在寄主病死前完成发育,存活比例因寄主感染病毒的时间和浓度而异．斜纹夜蛾被寄生后接种病毒(SINPV),距离寄生时间越长,饲毒浓度越低,寄生蜂完成发育的比例越大,但饲毒时间是主要影响因素．从感病幼虫体内发育成的侧沟茧蜂或曾经在感病寄主上产过卵的寄生蜂,以及通过人工方式使产卵器被病毒污染的寄生蜂,均能携带一定数量的病毒．通过产卵活动,侧沟茧蜂成蜂能在寄主幼虫个体间传递病毒．当寄生蜂在感病的寄主幼虫上产卵带毒后,平均可传递病毒给2．14头幼虫;发育于感病幼虫体内的寄生蜂,平均可传递病毒给2．45头幼虫．通过用病毒液浸茧或用混有病毒的蜂蜜饲喂成蜂等方式使产卵器污染病毒的寄生蜂,传毒效率随饲毒浓度增加而提高,平均可传递病毒1．45头和0．94头幼虫     

在受重金属Zn2+胁迫的斜纹夜蛾幼虫寄主上双斑侧沟茧蜂的生存与发育

通过在植食性昆虫斜纹夜蛾Spodoptera litura Fabricius幼虫人工饲料中添加不同浓度的Zn²⁺,测定了连续3代取食含不同Zn²⁺浓度饲料幼虫的血淋巴中Zn²⁺含量,并研究了被Zn²⁺胁迫的斜纹夜蛾幼虫对寄生性天敌双斑侧沟茧蜂Microplitis bicoloratus Chen生存与发育的影响。结果表明,斜纹夜蛾幼虫血淋巴中Zn²⁺含量随饲料中Zn²⁺浓度和幼虫取食世代数的增加而增加;Zn²⁺胁迫斜纹夜蛾幼虫对双斑侧沟茧蜂的寄生率、从寄生到结茧的时间、蛹期长短、成虫羽化率和成虫寿命等都有不同程度的影响,其中以第2代的寄生率和第1代的羽化率受影响最大,均随着Zn²⁺浓度的增大而降低。因此,寄主饲料中高浓度的Zn²⁺能通过食物链影响双斑侧沟茧蜂的生存和发育。     

甜菜夜蛾不同龄期幼虫被斑痣悬茧蜂寄生的风险分析

寄生蜂的寄主识别期是构建最优接受寄主模型的重要参数之一。本研究观察了斑痣悬茧蜂(Meteorus pulchricornis)对甜菜夜蛾(Spodoptera exigua)不同龄期幼虫的识别期,并首次用生存分析方法估计寄主被寄生的风险以及寄生经历对寄主识别期的影响。结果表明:在2.5h观察期内,除1龄寄主幼虫外,其他各龄(2~5龄)幼虫均被寄生;对首次寄主识别期的Cox回归模型拟合分析表明,与2龄寄主幼虫(参照虫龄)相比,3~5龄寄主幼虫被寄生的累计风险比率显著高于2龄寄主幼虫(2·6~4·0倍),而对再次寄主识别期的分析未发现3~5龄寄主幼虫与2龄幼虫之间存在显著差异。根据对首次与再次寄主识别期进行的生存曲线比较表明,对2~4龄幼虫的再次寄主识别期显著短于首次寄主识别期;说明寄生经历显著提高了寄生蜂的寄主识别期。由此推测,较高龄期甜菜夜蛾幼虫被无寄生经验斑痣悬茧蜂寄生的风险高于低龄幼虫。     

斑痣悬茧蜂对斜纹夜蛾不同虫龄幼虫的选择及后代发育表现

为探究容性寄生蜂对不同龄期寄主幼虫的选择性及其子代蜂发育表现的关联,通过双选试验观察了斑痣悬茧蜂(Meteorus pulchricornis)对斜纹夜蛾(Spodoptera litura)不同虫龄幼虫的寄生选择,并观察了与子代蜂适合度相关的特性表现.结果表明:斑痣悬茧蜂在4龄与5龄之间未表现出偏好,在2龄和3龄、3龄和4龄之间显著偏好较低虫龄;结茧率在不同寄主虫龄间无显著差异,羽化率随寄主虫龄增大而减小,寄生2、3龄幼虫的子代蜂显著高于寄生5龄;寄生5龄幼虫的子代蜂死亡率比寄生2龄的高2.5倍,比寄生3龄的高5.4倍.寄生3龄幼虫的子代蜂发育历期最短(11.9 d),比寄生4龄幼虫的短6.8 d,比寄生2龄幼虫的短4.7 d;子代蜂体型大小在寄生的寄主虫龄间无显著差异.根据研究结果推测,斑痣悬茧蜂在寄生时可能不是根据寄主龄期来评价寄主品质,而是基于寄主体型大小进行评价.     

几种因子对马尼拉侧沟茧蜂寄生效能的影响

马尼拉侧沟茧蜂Microplitis manilae是斜纹夜蛾Spodoptera litura的一种重要幼虫寄生蜂。本文以斜纹夜蛾2龄幼虫为寄主,在26±1℃、RH 65%±5%、L：D=12:12的人工气候箱内,研究生殖方式、雌蜂日龄、寄生时间段、雄蜂出现与否以及雄蜂密度等因子对其寄生效能的影响。结果表明：马尼拉侧沟茧蜂可营产雄孤雌生殖和两性生殖两种生殖方式,两种方式在亲代寄生率、子代羽化率和发育历期均无显著差异。随着雌蜂日龄的增加,其寄生率和子代性比显著降低,但子代发育历期随雌蜂日龄的增加而延长。马尼拉侧沟茧蜂在12:00-18:00时间段的寄生率、子代羽化率和性比最高,子代发育历期最短。当寄生蜂密度一定时,子代性比随着寄主密度的增加而显著增加;当寄主密度一定时,子代性比随着寄生蜂密度的增加而显著下降;雄蜂在场时,子代性比显著高于无雄蜂在场时。子代性比随着亲代雄蜂密度的增加而显著降低,但雄蜂密度对亲代寄生率,子代羽化率、发育历期无显著影响。     

斑痣悬茧蜂的寄主种间选择性及其子代蜂发育适合度表现

为检验基于经典搜寻理论的最优膳食模型的预测——产卵雌蜂应该选择最适于子代蜂发育的寄主种进行产卵,本研究以斑痣悬茧蜂(Meteorus pulchricornis)及其寄主斜纹夜蛾(Spodoptera litura)和粘虫(Mythimna separata)的幼虫为材料,在控制寄主体型大小和龄期影响的基础上,分别在体型大小相近和日龄相同的3个水平上观察了斑痣悬茧蜂对2种寄主幼虫的选择偏好,并观察了子代蜂生长发育适应度表现。在观察期(1h)内,当2种寄主幼虫的体型相近或者龄期相同的情况下,斑痣悬茧蜂对粘虫的产卵器刺扎次数以及寄生率(用结茧率表示)均高于斜纹夜蛾;而在斜纹夜蛾幼虫体内发育出的子代蜂茧重和体型均大于粘虫,成蜂寿命无显著差异。最后,对斑痣悬茧蜂的寄主选择和子代发育表现不一致现象进行了讨论。     

草地贪夜蛾与斜纹夜蛾解毒相关基因的比较分析

草地贪夜蛾Spodoptera frugiperda近期在中国为害猖獗,由于繁殖速度快,迁飞能力强,在本土呈现爆发趋势,严重为害了我国农作物。与本地近缘物种斜纹夜蛾Spodoptera litura相比,草地贪夜蛾更偏好玉米、水稻、小麦等禾本科农作物,且对多种化学杀虫剂及转基因Bt玉米产生抗性。寄主适应性以及杀虫剂抗性与解毒代谢相关蛋白密切相关。因此,本研究对这两种夜蛾科害虫的解毒代谢相关蛋白——细胞色素P450、谷胱甘肽转移酶(GST)及ABC转运蛋白进行了全基因组水平系统的搜集和数目比较,构建系统发育树并对P450和GST部分基因扩张分支进行氨基酸差异位点分析。结果显示,在草地贪夜蛾中共鉴定出213个P450基因、58个GST基因、102个ABC基因,其中P450基因与GST基因数目远远多于斜纹夜蛾(116,37),而ABC基因数目与斜纹夜蛾(99)接近。系统发育树分析表明,草地贪夜蛾P450在CYP6、CYP9以及CYP4功能簇,GST在部分进化分支上都发生了显著基因扩张,发生显著扩张的基因中有数个氨基酸突变,其中一些突变被预测可能影响蛋白质功能。但出乎意料的是,ABC亚家族B和E在斜纹夜蛾聚集成簇并发生了显著的基因扩张现象。以上结果暗示入侵种草地贪夜蛾和本地近缘物种斜纹夜蛾在抗性方面可能发展出各自独特的应对机制。本研究为解析草地贪夜蛾解毒抗性特征机制提供基因数据,为草地贪夜蛾的生物防治及抗性研究提供参考依据。     

甜菜夜蛾的饲养方法介绍

介绍一种甜菜夜蛾的室内饲养方法 ,采用本方法累代饲养甜菜夜蛾 8代 ,平均蛹重达 1 1 2 .9mg ,平均化蛹率 97% ,平均羽化率为 91 .3% ,室内饲养结果表明 ,该饲养方法可用于室内大量饲养甜菜夜蛾     

斜纹夜蛾（Spodoptera litura）的胚胎发育

本文利用实验胚胎学方法详细研究了斜纹夜蛾胚胎发育的全过程。结果表明：在２４±１℃的恒温条件下,仅需８７小时即可孵化出幼虫,同时证明了马氏管起源于外胚层。     

甜菜夜蛾cDNA文库的构建

以甜菜夜蛾Spodoptera exigua(Hübner)幼虫为材料建立了cDNA表达文库,经检测文库的初始滴度为1.1×105pfu/mL,重组率为97%,扩增后文库的滴度为5.4×107pfu/mL。用设计的2对引物筛选该文库,得到468 bp的1个片段,分析后证实是几丁质合成酶基因I保守区域的1个片段。该cDNA文库为进一步筛选甜菜夜蛾功能基因奠定了基础。     

甜菜夜蛾围食膜的蛋白质组鉴定

[目的]甜菜夜蛾Spodoptera exigua是农业的重要害虫,为害我国蔬菜等农作物的生长.围食膜(Peritrophic membrane,PM)是昆虫体内的第一道屏障,有助于昆虫食物消化过程和保护昆虫避免细菌或病毒的侵染.本研究选取甜菜夜蛾为实验对象,通过鉴定围食膜的总蛋白成分,为探讨围食膜与病原菌相互作用的生理机制奠定基础.[方法]选用人工饲料饲养的甜菜夜蛾5龄幼虫,剥离幼虫围食膜,利用强变性剂三氟甲磺酸(Trifluoromethane-sulfonic acid, TFMS)处理,并对围食膜蛋白进行质谱鉴定和生物信息学分析,使用BLAST鉴定蛋白的同源性,探究基因水平转移现象.[结果]本研究共鉴定出199个围食膜蛋白.这些鉴定的蛋白可富集于84条GO term(P＜0.05);此外,所鉴定的蛋白可被注释到KEGG的73条代谢通路中,并能形成多个蛋白互作网络,分别参与能量代谢、蛋白水解、过氧化氢代谢、免疫等多种过程.同时,鉴定出与抗逆性相关蛋白,具有解毒代谢等功能,提高昆虫对农药和恶劣环境的抗性.[结论]本研究对鉴定出的199个围食膜蛋白进行分析,初步揭示围食膜潜在的生物学功能,并提出一些害虫控制思路,为新型杀虫剂的研发提供了理论基础.     

Interaction of Xestia c-nigrum granulovirus with peritrophic matrix and Spodoptera litura nucleopolyhedrovirus in Spodoptera litura

Xestia c-nigrum granulovirus (XcGV) was tested for its ability to increase Spodoptera litura nucleopolyhedrovirus (SINPV) infection in larvae of S. litura (F.). The interaction of XcGV with peritrophic matrix and SINPV in S. litura also was studied to account for the synergism. In dose-response bioassays with a constant XcGV concentration of 5-mg/ ml capsules and SINPV concentration that varied from 10(3) to 10(7) polyhedral inclusion bodies (PIB) per larva, XcGV increased the virulence of SINPV infection in fifth instars of S. litura. The lethal concentration of 50% individuals (LC50) of SINPV combined with XcGV was 3.35 x 10(5)PIB/ml, which was significantly lower than that of SINPV alone (2.17 x 10(6)). Compared with 10(7) PIB/ml SINPV alone, the lethal time of 50% individuals (LT50) of 10(7) PIB/ml SINPV combined with XcGV was not significantly shortened. In addition, no significant improvement in the activity and killing speed of SINPV progeny was noted after propagation with XcGV, indicating that native characters of SINPV associated with viral potency were not altered by XcGV. Investigation via environmental scanning electronic microscopy showed that the peritrophic matrix (PM) of S. litura exposed to XcGV or XcGV enhancin, or the combination treatment, was markedly disrupted. The outer surface of the PM was loose, or ruptured, which potentially facilitated the passage of virions through the PM. Therefore, it is reasonable to conclude that the synergy between XcGV and SINPV was closely associated with the disruption of the PM in S. litura.     

Sex pheromone of the cotton leafworm, Spodoptera littoralis

cis-9,trans-11-Tetradecadien-1-ol acetate (A) and cis-9,trans-12-tetradecadien-1-ol acetate (B), the same compounds as the female sex pheromone of Spodoptera litura, were identified as major components of the female sex pheromone of the cotton leafworm, Spodoptera littoralis. Compounds A and B were individually active, but the activity was synergistically enhanced by mixing the two compounds. The male response was optimal with mixture ranging from 5 : 1 to 20 : 1 of compounds A and B, respectively. Fifty per cent of the male moths of S. littoralis responded to the 20 : 1 mixture at the 10^?7 μg level; they responded at a concentration 100-fold lower than did male moths of S. litura. A partially purified extract of females of S. litura stimulated male moths of S. littoralis. Similarly a partially purified extract of S. littoralis was also active for the male moths of S. litura. The extract of females of S. litura, however, was 1000 times less active for male moths of S. littoralis than was the exrtact of females of S. littoralis, suggesting that a compound(s) is present in the extract of S. litura that inhibits the response of males of S. littoralis.     

Heritability of immune function in the caterpillar Spodoptera littoralis

Phenoloxidase (PO) is believed to be a key mediator of immune function in insects and has been implicated both in non-self recognition and in resistance to a variety of parasites and pathogens, including baculoviruses and parasitoids. Using larvae of the Egyptian cotton leafworm, Spodoptera littoralis, we found that despite its apparent importance, haemolymph PO activity varied markedly between individuals, even amongst insects reared under apparently identical conditions. Sib-analysis methods were used to determine whether individuals varied genetically in their PO activity, and hence in one aspect of immune function. The heritability estimate of haemolymph PO activity was high (h(2) = 0.690 +/- 0.069), and PO activity in the haemolymph was strongly correlated with PO activity in both the cuticle and midgut; the sites of entry for most parasites and pathogens. Haemolymph PO activity was also strongly correlated with the degree to which a synthetic parasite (a small piece of nylon monofilament) was encapsulated and melanized (r = 0.622 +/- 0.142), suggesting that the encapsulation response is also heritable. The mechanism maintaining this genetic variation has yet to be elucidated.     

Insecticidal activity of the chitinase from the Spodoptera litura nucleopolyhedrovirus

Baculovirus chitinase gene (chiA) is a late gene essential for liquefying the host insect at a late stage of infection for its hydrolyzing chitin function. In a previous report, baculovirus ChiA has been shown to offer many interesting new opportunities for pest control. Recently, a putative chiA gene was identified in the Korean isolate of the Spodoptera litura nucleopolyhedorvirus (SpliMNPV‐K1) genome. The open reading frame (ORF) contains 1692 nucelotides and encodes a protein of 563 amino acids with a predicted molecular weight of about 62.6 kDa. To study the insecticidal activity of ChiA from SpliMNPV‐K1, we constructed a recombinant AcMNPV, Ap‐SlChiA, which is designed to express the ChiA under the control of a polyhedrin promoter. Western blot analysis indicated that ChiA was successfully expressed by this recombinant virus. Chitinase assay revealed that the chitobiosidase and endochitinase activity of the recombinant virus was 2.5‐ and 3.9‐flods higher than those of wild‐type AcMNPV, respectively. In addition, the recombinant virus showed higher evident insecticidal activity against 3rd instar larvae of Spodotera exigua than that of the AcMNPV. These results suggest that the chiA gene from SpliMNPV‐K1 could be successfully applied to improve pathogenicity of baculoviruses.     

Electron microscope study on the replication of Autographa nuclear polyhedrosis virus and Spodoptera nuclear polyhedrosis virus in Spodoptera exigua

A comparative study of Spodoptera nuclear polyhedrosis virus (NPV) and Autographa NPV replication in Spodoptera exigua revealed some cytopathologic differences. Infection with Spodoptera NPV was accompanied by electron-dense intranuclear granules. Autographa infection within the midgut led to secretion within the lumens of the goblet cells of paracrystalline arrays of small, round particles, 9.5 nm in diameter. Autographa virus was also observed in various stages of possible replication within the cytoplasm.