黄斑卷蛾雄蛾对性信息素的行为反应

分别在风洞中和田间观察了黄斑卷蛾Acleris fimbriana Thunberg et Becklin雄蛾对合成性信息素三种成分（E11,13-14∶Ald, E11,13-14∶Ac和E11-14∶Ac）及其不同组合的行为反应。在风洞中,主要活性成分E11,13-14∶Ald能引起雄蛾完成从兴奋到搜索释放源的行为反应,但雄蛾对单个组分E11,13-14∶Ac 或 E11-14∶Ac不呈现任何行为反应。当释放源为双组分 E11,13-14∶Ald＋E11,13-14∶Ac （6∶4）或三组分E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac（6∶4∶1）时,可以明显增加雄蛾定向飞行和到达释放源的数量。三组分 E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac的比例为6∶4∶1时,500 μg剂量效果最好。田间试验结果表明,E11,13-14∶Ald单独使用表现出良好的诱蛾活性,其诱蛾量为活雌蛾的1.9倍,而E11,13-14∶Ac和E11-14∶Ac则不具有诱蛾活性。E11,13-14∶Ac对E11,13-14∶Ald有明显的增效作用,三组分E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac（6∶4∶1）诱芯的诱蛾效果最好。     

赤松毛虫性信息素次要组分的鉴定——组分、电生理和田间效果

用带有极性和非极性毛细柱的气相色谱(GC)分析赤松毛虫Dendrolimus spectabilis性信息素腺体提取物,发现腺体中除含有已鉴定的性信息素(顺,反)-5,7-十二碳二烯醇(Z5,E7-12∶OH)外,还有微量的(顺,反)-5,7-十二碳二烯醛(Z5,E7-12∶Ald)和(顺,反)-5,7-十二碳二烯乙酸酯(Z5,E7-12∶Oac),三种成分以100∶5-6±5-4∶3-2±1-8的比例存在。使用气相色谱-质谱选择性离子检测法（GC-MS-SIM）分析赤松毛虫腺体提取物,发现腺体中确实含有微量的Z5,E7-12∶Oac和痕量的Z5,E7-12∶Opr。赤松毛虫腺体提取物的气相色谱和触角电位检测联用（GC-EAD）分析发现只有Z5,E7-12∶OH能激起EAD反应,然而使用较高剂量的标准化合物进行GC-EAD分析发现Z5,E7-12∶OH、Z5,E7 12∶Oac和(顺,反)-5,7-十二碳二烯丙酸酯(Z5,E7-12∶Opr)均能刺激起EAD反应,而Z5,E7-12∶Ald则不能。触角电位（EAG）剂量-反应关系研究表明,当剂量变化范围在0.01～1 μg时,雄虫触角对Z5,E7-12∶OH最敏感,对Z5,E7-12∶Oac和Z5,E7-12∶Opr次之。田间试验表明,由Z5,E7-12∶OH, Z5,E7-12∶Oac和Z5,E7-12∶Opr配制的三组分诱芯,其诱蛾量显著高于由Z5,E7-12∶OH组成的单组分或是它与其乙酸酯或丙酸酯组成的两组分诱芯,当Z5,E7-12∶OH,Z5,E7-12∶Oac和Z5,E7-12∶Opr的比例为100∶3∶25时,诱蛾效果最佳。在上述三组分混合物中加入一定量的Z5,E7-12∶Ald,则对诱蛾有明显的抑制作用。上述事实表明,Z5,E7-12∶Oac和Z5,E7-12∶Opr是赤松毛虫性信息素的两种次要组分,而Z5,E7-12∶Ald则是信息素的抑制剂。     

粘虫雄蛾触角对其性信息素的电生理反应

用自行组装的触角电位仪,测定了粘虫Mythimna separata雄蛾蛾龄对标准化合物顺-11-十六碳烯醛(Z11-16：A1d)、顺-9-十六碳烯醛(Z9-16:Ald)和十六碳醛(16：A1d)的EAG反应的影响,分析了雄蛾触角对3种标准化合物的剂量-反应关系,发现粘虫雄蛾对Zll-16,Ald和Z9-16：Ald的剂量-反应曲线呈现出典型的“S”型,并且反应阐值较低。而对16：A1d几乎没有反应。最为重要的是检测了粘虫雄蛾对雌蛾腺体提取物的EAG反应,反应值的大小与样品中所提取的雌蛾腺体数目成正比。通过检测粘虫雄蛾对羽化不同天数,以及同一天羽化、在暗期不同时辰提取的雌蛾腺体提取物的EAG反应,证实了粘虫雄蛾的反应曲线与雌蛾释放性信息素的时辰节律呈正相关。还比较了烟青虫和粘虫雄蛾对粘虫雌蛾腺体提取物的EAG反应,间接证实了粘虫雌蛾腺体提取物中可能含有次要组分Z9-16;A1d。     

棉铃虫成虫对性信息素的电生理和行为反应研究

通过EAG和风洞实验,研究了棉铃虫雌雄成虫对性信息素组分和诱芯(Z-11-16Ald∶Z-9-16Ald=97∶3)的电生理反应。其中棉铃虫雌、雄蛾对诱芯的平均EAG反应测定值分别为1.06mV和4.32mV,分别高出对照(无性信息素空白诱芯)0.67mV和0.366mV,差异均达到极显著水平(雌蛾：t＝25.020, P≤0.01;雄蛾：t＝44.269,P≤0.01);棉铃虫雌蛾对性信息素组分(Z-11-16-Ald和Z-9.16Ald)的EAG反应值随浓度增加而增加;雄蛾在被剪除触角后与雌蛾不能正常交配,而雌蛾在被剪除触角后仍有40%的交配率,比正常雌雄蛾的交配率(70%)有所下降;在风洞实验中,雄蛾没有顺风远离诱源的飞行行为,趋向诱源的比率为81.8%,与对照有显著差异。研究表明性信息素组分对棉铃虫的交配活动有明显的影响。     

雄性棉铃虫感受性信息素的分子和神经机制研究进展

棉铃虫Helicoverpa armigera主要借助于性信息素通讯完成雌雄识别,实现交配和种群繁衍。关于棉铃虫感受性信息素机制的研究一直是我国化学生态学领域的热点和重心,研究结果有助于开发和改进棉铃虫防治的性引诱剂。本文将对棉铃虫雄虫感受雌虫释放的性信息素的机制进行综述,以期为深入研究棉铃虫及其他相关昆虫的性信息素感受的分子和神经机理提供参考。棉铃虫雌虫性信息素腺体合成和释放多种长链、饱和或非饱和的脂肪醛和醇等化合物,其中Z11-16:Ald为主要性信息素成分,Z9-16∶Ald和Z9-14∶Ald为次要性信息素成分,不同组分按一定比例混合可明显增强对雄性棉铃虫的引诱效果,而化合物Z11-16∶OH和高剂量的Z9-14∶Ald对性信息素引诱活性具有明显的抑制效果。相应地,雄性棉铃虫触角上A,B和C 3种类型的毛形感器能够感受这些信息化合物。A类型毛形感器内表达受体OR13感受Z11-16∶Ald,B类型毛形感器内表达OR14b感受Z9-14∶Ald,C类型毛形感器内表达OR6和OR16感受Z9-16∶Ald,Z9-14∶Ald,Z11-16:Ac和Z11-16∶OH。受体的表达位置和...     

黄杨绢野螟雌蛾性信息素的鉴定及诱蛾活性

【目的】研究旨在深入探讨中国黄杨绢野Diaphania perspectalis 的雌蛾性信息素组成及诱蛾活性。【方法】利用气质联用仪（GC-MS）对黄杨绢野螟正常型性成熟雌蛾的性腺体提取物和合成标样比较分析,并用反-11-十六碳烯醛(E11-16:Ald) 、顺-11-十六碳烯醛（Z-11-16:Ald）、顺-9-十六碳烯醛（Z-9-16:Ald)、顺-11-十六碳烯醇（Z-11-16:OH)等物质进行触角的电生理测定,最后开展田间诱集比较试验以筛选出最佳性信息素混合物。【结果】Z-11-16:Ald为中国黄杨绢野螟正常型性信息素主要组分,E-11-16:Ald的含量极低,Z-11-16:OH未检测到。正常型雄性黄杨绢野螟触角对Z-11-16:Ald, E-11-16:Ald, Z-9-16:Ald和Z-11-16:OH产生强烈的EAG反应,并随着浓度的提高而显著增加;而对Z-11-16:Ac和E-11-16:Ac的嗅觉反应较弱,低于对植物绿叶气味顺3-己烯乙酸酯（Z-3-6:Ac）的反应。单一Z-1-16:Ald对正常型雄性黄杨绢野螟具有强烈的诱集效果,加入E-11-16:Ald有一定的增效作用,但在统计上则不显著。单一Z-11-16:Ald组分对黑化型雄性黄杨绢野螟无引诱活性,必需加入一定比例的E-11-16:Ald才显示诱蛾活性。Z-11-16:Ald:E-11-16:Ald的比例为250 μg:250 μg时诱集到的黑化型雄性黄杨绢野螟数量最多,而Z-11-16:Ald:E-11-16:Ald的比例为429 μg:71 μg时则诱集到的正常型雄性黄杨绢野螟数量最多。同时,单一Z-11-16:Ald也可引诱大量雄性粘虫Mythimna separata,但E-11-16:Ald抑制其活性。【结论】中国黄杨绢野螟的性信息素主成分是Z-11-16:Ald,单一组分即可在田间强烈引诱雄蛾,E-11-16:Ald的功能只起到微弱的增效作用,但也可能起种的专一性的作用。正常型与黑化型黄杨绢野螟对性信息素的嗅觉反应存在差异,黑化型黄杨绢野螟的性信息素接近日本种,即性信息素组成为Z-11-16:Ald和E-11-16:Ald 的混合物,其比例为1:1,且E-11-16:Ald为必需。     

雄性棉铃虫感受性信息素的分子和神经机制研究进展

棉铃虫Helicoverpa armigera主要借助于性信息素通讯完成雌雄识别,实现交配和种群繁衍。关于棉铃虫感受性信息素机制的研究一直是我国化学生态学领域的热点和重心,研究结果有助于开发和改进棉铃虫防治的性引诱剂。本文将对棉铃虫雄虫感受雌虫释放的性信息素的机制进行综述,以期为深入研究棉铃虫及其他相关昆虫的性信息素感受的分子和神经机理提供参考。棉铃虫雌虫性信息素腺体合成和释放多种长链、饱和或非饱和的脂肪醛和醇等化合物,其中Z11-16:Ald为主要性信息素成分,Z9-16∶Ald和Z9-14∶Ald为次要性信息素成分,不同组分按一定比例混合可明显增强对雄性棉铃虫的引诱效果,而化合物Z11-16∶OH和高剂量的Z9-14∶Ald对性信息素引诱活性具有明显的抑制效果。相应地,雄性棉铃虫触角上A, B和C 3种类型的毛形感器能够感受这些信息化合物。A类型毛形感器内表达受体OR13感受Z11-16∶Ald,B类型毛形感器内表达OR14b感受Z9-14∶Ald,C类型毛形感器内表达OR6和OR16感受Z9-16∶Ald, Z9-14∶Ald, Z11-16:Ac和Z11-16∶OH。受体的表达位置和功能与不同类型毛形感器的电生理反应特性相一致。钙离子成像证明在棉铃虫触角叶内的3个扩大型神经纤维球接受这些气味信息,其中神经纤维球云状体接受Z11-16∶Ald,背中间后侧纤维球接受Z9-16∶Ald,背中间前侧纤维球接受Z9-14∶Ald, Z11-16∶Ac和Z11-16∶OH。这些研究成果在感器、受体和脑中枢水平上揭示了棉铃虫感受性信息素的机制,在这些研究基础上,我们认为需要深入开展以下方面的研究：(1)进一步鉴定相关性信息素受体的功能和定位;(2)深入研究脑内嗅觉高级中枢对性信息素信息的处理和整合神经机制;(3)明确棉铃虫性信息素感受受到寄主植物、光周期、温度、湿度等环境因素的影响及机制。     

温度对粘虫产生和释放性信息素规律的影响

在21℃饲养的粘虫雌蛾腺体提取物中Zll－16：Aid含量峰值时间是羽化后第8～9天;25℃是羽化后第4～5天,27℃是羽化后第3～4天。低温不仅推迟了粘虫雌蛾求偶和释放性信息素的时间,而且降低了腺体中性信息素的滴度。在27℃,粘虫雌蛾腺体中Zll－16：Ald峰值的平均值达15ng;在25℃时为10ng,而在21℃时,只有5ng。由此可见,低温环境明显抑制粘虫雌蛾的性发育,延缓了性成熟。     

六星黑点豹蠹蛾求偶行为与性信息素产生和释放的时辰节律

六星黑点豹蠹蛾Zeuzera leuconotum Butler(Lepidoptera:Cossidae)是一种重要的园林害虫。为研究利用其性信息素防控六星黑点豹蠹蛾,在光周期L∶D=14∶10、温度19—32℃、相对湿度75%—85%条件下,对雌蛾求偶行为进行了观察;采用腺体提取法和瓶内收集法分别制备了不同日龄在同一时辰、同日龄在不同时辰的雌蛾性信息素粗提物,然后测定雄蛾触角对各种性信息素提取物的触角电位反应;以雄蛾对腺体提取物的EAG值表示性信息素的产生量,对瓶内收集物的EAG值表示释放量,检测性信息素产生与释放的时辰节律。结果表明:雌蛾求偶均发生在暗期;雌蛾求偶率与日龄有关,其中2日龄雌蛾求偶率最高,平均为86.7%;不同日龄雌蛾求偶高峰期均在进入暗期4—6h期间;随着虫龄的增加,求偶高峰期前移。雌蛾羽化当晚体内即可产生性信息素,并且向体外释放,但量较少;2日龄雌蛾产生和释放的性信息素量最大;雌蛾腺体中性信息素含量从进入暗期后逐渐增加,在暗期5h含量最高,随后逐渐减少;雌蛾释放性信息素从暗期4h开始,至暗期6h释放量最大。通过林间处女雌蛾诱捕试验证明了六星黑点豹蠹蛾的求偶行为与性信息素产生和释放在时辰节律上具有一致性。     

利用超微量技术分析粘虫单腺体性信息素的化学组成

通过选择提取溶剂、改进提取方法以及毛细柱气相色谱检测条件,摸索出粘虫 Mythimna separata Walker单腺体提取和分析方法;并且确定了单个求偶雌蛾腺体提取物的化学组成、含量和相对比例。讨论了粘虫求偶雌蛾性信息素腺体提取物中各组分含量的个体差异。     

Neurons discovered in male Helicoverpa zea antennae that correlate with pheromone-mediated attraction and interspecific antagonism

Responses of single receptor neurons in the antennae of male Helicoverpa zea to sex pheromone components and to behavioral antagonists were recorded using a cut-sensillum extracellular recording technique. Three types of sensilla were identified from sampling 325 male-specific sensilla trichodea located at the lateral edge of antennomeres. The majority of these sensilla (71%) contained a receptor neuron tuned to the principal sex pheromone component (Z)-11-hexadecenal. A second sensillar type (10%) contained a receptor neuron that responded only to (Z)-9-tetradecenal. A third sensillar type (19%) contained a large-spiking neuron tuned to the secondary pheromone component (Z)-9-hexadecenal, but this neuron also could be stimulated to equivalent spike frequencies by the same emitted amounts of (Z)-9-tetradecenal. A smaller-spiking neuron in this sensillar type responded to two compounds known to act only as behavioral antagonists, (Z)-11-hexadecen-1-ol and (Z)-11-hexadecenyl acetate, and to (Z)-9-tetradecenal. Cross-adaptation studies confirmed the presence of one large- and one small-spiking neuron in the third sensillar type. Dose-response studies correlated to collected stimuli amounts showed that the large-spiking neuron in the third sensillar type was equally tuned to (Z)-9-hexadecenal and (Z)-9-tetradecenal, whereas the smaller-spiking neuron was far more sensitive to (Z)-11-hexadecen-1-ol and to (Z)-11-hexadecenyl acetate than to (Z)-9-tetradecenal. Accepted: 29 September 1997     

Identification of a pheromone blend attractive to Manduca sexta (L.) males in a wind tunnel

Analyses of solvent rinses of the external surfaces of pheromone glands excised from calling female tobacco hornworm moths, Manduca sexta (L.), revealed the presence of the following compounds: (Z)-9-hexadecenal, (Z)-11-hexadecenal, (E)-11-hexadecenal, hexadecanal, (E,Z)-10,12-hexadecadienal, (E,E)-10,12-hexadecadienal, (E,E,Z)-10,12,14-hexadecatrienal, (E,E,E,)-10,12,14-hexadecatrienal, (Z)-11-octadecenal, (Z)-13-octadecenal, octadecanal, and (Z,Z)-11,13-octadecadienal. The two trienals were identified by mass and PMR spectral analyses and by ozonolyses, and their structures were confirmed by synthesis. In a wind tunnel male tobacco hornworm moths exhibit the same behaviors in response to a synthetic blend of all of the components, the gland rinse, or a calling female. Both (E,Z)-10,12-hexadecadienal and (E,E,Z)-10,12,14-hexadecatrienal are required to stimulate males to complete the characteristic behavioral sequence: anemotaxis, approaching and touching the pheromone source, and bending their abdomens in apparent copulatory attempts. The other components of the blend may play more subtle roles.     

The significance of major pheromone components and interspecific signals as expressed by receptor neurons in the oriental tobacco budworm moth,Helicoverpa assulta

Receptor neuron specificities for intra- and interspecific chemical signals were determined in males of Helicoverpa assulta, by testing single neurons for twelve heliothine produced compounds and two chemical analogues. Three types of receptor neurons were identified in the male specific sensilla trichodea type 1.

1. One large group of neurons (29 out of 63) was tuned to the major pheromone component (Z)-9-hexadecenal, in contrast to results obtained previously in a related species, where the information from this compound seems to be mediated via neurons tuned to (Z)-9-tetradecenal.
2. Another group of neurons (28/63) was tuned to (Z)-9-tetradecenal which is not produced by the conspecific females. These neurons and those tuned to the major pheromone component, always appearing together, are probably located in the same sensillum. Their large number suggests that (Z)-9-tetradecenal mediates an important message in this species, probably causing interspecific interruption.
3. The third group of neurons (6/63) was tuned to the second principal pheromone component (Z)-11-hexadecenal. These neurons showed similar specificities as the corresponding type of neurons in related species, indicating a conservation of their membrane receptors through evolution. In contrast, the (Z)-9-tetradecenal receptor neurons in H. assulta showed a different specificity than their counterparts in the related species, suggesting that their receptor proteins have evolved differently.

     

Monoenyl hydrocarbons in female body wax of the yellow peach moth as synergists of aldehyde pheromone components

The non-polar components of female body wax and pheromone gland extracts of the yellow peach moth synergistically enhanced male behavioral responses from close to pheromone sources in wind tunnel tests when mixed with an aldehyde pheromone blend. When the non-polar fractions (NPFs) of female body wax were further separated by column chromatography, synergistic activities were found in the 3 and 50% ether in hexane fractions, and they additively increased male responses. The main components of the first fraction were (Z)-9-tricosene, (Z)-9-pentacosene, (Z)-9-heptacosene, (Z)-9-nonacosene and (Z)-9-hentriacontene. Only (Z)-9-heptacosene showed a significant synergistic effect in enhancing male responses, but the other components had no effect. A mixture of the five monoenyl hydrocarbons lost activity at lower doses than 5 ng. Natural ratios of these hydrocarbons in the female body wax and pheromone gland extracts were similar, but the amount of (Z)-9-heptacosene in the female body wax was significantly higher than in the pheromone gland extracts. We conclude that (Z)-9-heptacosene increases male responses to aldehyde pheromones, and unknown component(s) in the 50% ether in the hexane fraction are required for full synergistic enhancement by the NPFs of the female body wax and the pheromone gland extracts.     

A comparison of responses from olfactory receptor neurons of<Emphasis Type="Italic"> Heliothis subflexa</Emphasis> and<Emphasis Type="Italic"> Heliothis virescens</Emphasis> to components of their sex pheromone

Single-cell electrophysiological recordings were obtained from olfactory receptor neurons in sensilla trichodea on male antennae of the heliothine species Heliothis subflexa and the closely related congener H. virescens. A large percentage of sensilla (72% and 81%, respectively, of all sensilla sampled) contained a single odor-responsive receptor neuron tuned to the major pheromone component of both species, Z-11-hexadecenal. A second population of sensilla on H. subflexa antennae (18%) housed receptor neurons that were tuned to Z-9-hexadecenal but also responded with less sensitivity to Z-9-tetradecenal. A similar population of sensilla (4%) on H. virescens male antennae housed receptor neurons that were shown to be tuned specifically only to Z-9-tetradecenal, with no response to even high dosages of Z-9-hexadecenal. A third population of sensilla (comprising 8% and 16% of the sensilla sampled in H. subflexa and H. virescens, respectively) housed two olfactory receptor neurons, one of which was tuned to Z-11-hexadecenyl acetate and the other tuned to Z-11-hexadecenol. In H. subflexa the Z-11-hexadecenyl acetate-tuned neuron also responded to Z-9-tetradecenal with nearly equivalent sensitivity. The behavioral requirements of males of these two species for distinct pheromonal blends was, therefore, reflected by the subtle differences in the tuning properties of antennal olfactory receptor neurons.Abbreviations MGC macroglomerular complex - ORN olfactory receptor neuron - Z9–14:Ald (Z)-9-tetradecenal - Z9–16:Ald (Z)-9-hexadecenal - Z11–16:Ac (Z)-11-hexadecenyl acetate - Z11–16:Ald (Z)-11-hexadecenal - Z11–16:OH (Z)-11-hexadecenol     

Geographic variation of sex pheromone and mitochondrial DNA in Diatraea saccharalis (Fab., 1794) (Lepidoptera: Crambidae)

(9Z,11E)-hexadecadienal and (Z11)-hexadecenal, the main sex pheromone components of the sugarcane borer, Diatraea saccharalis, were identified and quantified from four Brazilian and one Colombian populations using GC-EAD, GC-MS and GC analyses. Three different ratios were observed, 9:1, 6:1, and 3:1. The pheromone concentration for the major component, (9Z,11E)-hexadecadienal, varied from 6.8 ng/gland to 21.9 ng/gland and from 1.7 ng/gland to 6.5 to the minor component, (Z11)-hexadecenal. The 25 D. saccharalis cytochrome oxidase II sequences that were analyzed showed low intra-specific variation and represented only 11 haplotypes, with the most frequent being the one represented by specimens from São Paulo, Paraná, and Pernambuco states. Specimens from Colombia showed the highest genetic divergence from the others haplotypes studied. Data on the genetic variability among specimens, more than their geographic proximity, were in agreement with data obtained from analyses of the pheromone extracts. Our data demonstrate a variation in pheromone composition and a covariation in haplotypes of the D. saccharalis populations studied.     

Reidentification of pheromone composition of Sparganothis sulfureana (Clemens) and evidence of geographic variation in male responses from two US states

GC-EAD analyses of pheromone gland extracts of calling female Sparganothis sulfureana revealed at least 6 compounds that consistently elicited antennal responses from male antennae. In addition to the major pheromone compound, (E)-11-tetradecenyl acetate (E11–14:OAc), which was previously reported, the other compounds were found to be (E)-9-dodecenyl acetate (E9–12:OAc), (Z)-9-dodecenyl acetate (Z9–12:OAc), (Z)-9-tetradecenyl acetate (Z9–14:OAc), (Z)-11-tetradecenyl acetate (Z11–14:OAc), and (E)-11-tetradecenol (E11–14:OH). Tetradecyl acetate, hexadecyl acetate and hexadecenyl acetates were also present in the extracts, but elicited no EAG response from male antennae. Wind tunnel tests demonstrated that males from New Jersey responded equally well to a blend containing five pheromone components in relative to the pheromone glands of calling females. Different male-response profiles from field-trapping tests conducted in the states of Wisconsin and New Jersey were observed, respectively. Significantly higher numbers of male S. sulfureana were caught in New Jersey in traps baited with the binary blend of E11–14:OAc (30 μg) with 1% of Z11–14:OAc, but males from Wisconsin responded equally well to traps containing blends of E11–14:OAc with 0–10% of Z11–14:OAc. The addition of more than 10% of Z11–14:OAc to the primary pheromone compound reduced male captures significantly in both states. Male catches were doubled by adding E9–12:OAc and E11–14:OH to the most attractive binary blend in both states. The trapping test with caged live virgin female moths showed that males in Wisconsin preferred females from the local population than those from New Jersey. The differences in male responses observed may indicate the existence of pheromone polymorphism in this species.     

Effect of Larvae Treated with Mixed Biopesticide Bacillus thuringiensis - Abamectin on Sex Pheromone Communication System in Cotton Bollworm,Helicoverpa armigera

Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis - abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD₂₀). The adult male survivors from larvae treated with BtA exhibited a higher percentage of “orientation” than control males but lower percentages of “approaching” and “landing” in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11–16:Ald) and Z-9-hexadecenal (Z9–16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11–16:Ald and Z9–16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H.armigera moths that may contribute to assortative mating.     

Female sex pheromone components of the cotton bollworm, Heliothis armigera

Detailed examination of abdominal tip extracts from adult female Heliothis armigera revealed the presence of two components which elicit electroantennographic responses from the male moth. These olfactory stimulants have been fully identified as (Z)-11-hexadecenal (I) and (Z)-11-hexadecen-1-ol(II), and detected in airborne volatiles from a ‘calling’ female moth. A third olfactory stimulant was detected only in female tip extracts from some moths of Malawi origin, and this was tentatively identified as (Z)-9-hexadecenal (III). No other olfactory stimulants could be found, although hexadecenal (IV) and 1-hexadecan-1-ol (V) were detected by gas chromatography. In field tests in Malawi, (Z)-11-hexadecenal (I) attracted a few male H. armigera moths to traps but was very much less attractive than the virgin female moth. The attractiveness of (I) was not consistently affected by addition of alcohol (II), aldehydes (III) and (IV), or (E)-11-hexadecenal. Significant numbers of male Earias biplaga moths were found to be attracted to (Z)-11-hexadecenal (I).