【作者】 黄安平；

【导师】 邹学校； 包小村；

【作者基本信息】 中南大学 ， 植物学， 2012， 博士

【摘要】 茶刺蛾(Iragoides fasciata Moore)属鳞翅目刺蛾科,是茶树[Camellia sinensis (L.) O. Kuntze]的主要害虫之一。在一定条件下容易爆发成灾,它不但造成茶叶减产,甚至导致茶树死亡,而且严重妨碍了采茶与田间作业。茶刺蛾的防治目前主要依靠化学防治,鉴于化学农药的负面影响,新的无公害防治策略研究迫在眉睫。棒须刺蛾寄蝇(Chaetexorista palpis Chao)属于双翅目寄蝇科,我们在田间和室内观察发现,棒须刺蛾寄蝇是茶刺蛾新发现的寄生天敌,是茶园中影响茶刺蛾种群发生的重要寄生天敌。本文对茶树、茶刺蛾和棒须刺蛾寄蝇之间的化学通讯进行了探索,旨在为茶刺蛾的防治提供理论依据。茶园观察发现,茶刺蛾危害的茶园的棒须刺蛾寄蝇数量明显多于未危害的茶园。推测茶树被茶刺蛾危害后释放了特定的信号物质,这些物质在棒须刺蛾寄蝇寄主定位中起着关键的作用。为了证实这一猜想,我们研究了茶刺蛾危害对茶树挥发性有机物释放的影响,分别应用同时萃取蒸馏法和顶空动态吸附两种方法收集被茶刺蛾危害和未危害的茶叶的挥发性有机化合物,并用气相色谱质谱仪联用技术分析。前一个试验结果如下：未受害枝叶挥发性有机化合物共有63种组分,主要由酯类、醇类、烃类、酮类、杂环化合物、醛类、有机酸和醚类组成,烃类物质的相对含量占19.05%,而受害枝叶释放出的挥发物中烃类物质的相对含量增加到26.79%,反式-橙花叔醇、雪松醇、邻苯二甲酸二丁酯和邻苯甲酸二异丁酯的相对含量显著增加,此外,产生了32种新的组分,包括10种酯类、5种醇类、5种烯烃类、4种杂环类、3种芳香烃类、3种烷烃类、1种醛和1种酮。后一个试验结果如下：未受茶刺蛾危害的枝叶有挥发性有机物74种组分,其挥发物的组成同前者相似。与未受茶刺蛾危害枝叶的挥发物组分相比较,受害后酯类、醛类和烃类的种类数量和所占相对含量都有显著变化。醇、杂环化合物、醚和有机酸类化合物在种类数量和相对含量上变化不大。受害后,4-异丙基甲苯、蒎烯、1-乙基-2,4-二甲基苯、4-乙基甲苯、3-乙基-甲苯、6-甲基庚烯[5]酮[2]和1,2,4-三甲基苯的相对含量显著增加。新产生54种化合物,其中烯烃14种,芳香烃12种,酯8种,烷烃8种,酮5种,醇3种,醛2种,有机酸和杂环类各1种。值得注意的是受害后萜类化合物的种类数量和相对含量均有显著的变化,暗示这些化合物可能在棒须刺蛾寄蝇的寄主寻找过程中发挥作用。研究结果为筛选引诱天敌昆虫的化学信息素,并应用其防控茶刺蛾的研究奠定一定的基础。为了筛选茶刺蛾和棒须刺蛾寄蝇的引诱剂,我们研究了茶刺蛾雌雄蛾对属于4个化合物种类的26种茶树相关的挥发物和2种混合物的电生理反应和棒须刺蛾寄蝇雌雄个体对属于5个化合物种类的27种茶树相关的挥发物的反应。结果表明大多数化合物都能引起茶刺蛾和棒须刺蛾寄蝇触角较大的电生理反应,茶刺蛾和棒须刺蛾寄蝇对不同的化合物和化合物种类之间的反应存在差异,雌雄个体对多数化合物的反应也有差异。一般茶刺蛾雄蛾对大多数化合物的反应要强于雌蛾,而棒须刺蛾寄蝇则刚好相反。茶刺蛾雌雄蛾对倍半萜化合物的反应相对其它种类的化合物要弱些。剂量反应试验表明茶刺蛾对化合物的反应在性别和浓度上都存在差异,也说明了雌雄个体电生理反应存在二型性。在所有化合物中,雌性棒须刺蛾寄蝇对顺-3-己烯-1-醇的反应强烈,而雄性个体对顺-3-己烯乙酸酯的反应最大。绿叶挥发物能引起较大的反应,推测其在茶刺蛾和棒须刺蛾寄蝇的寄主定位中起到重要的作用。为了解释茶刺蛾雌雄蛾对茶树挥发物电生理反应的差异性,对其触角和触角感受器进行扫描电镜观察,茶刺蛾雌雄蛾触角表面一共发现了8种类型的感受器：毛形感受器、锥形感受器、刺形感受器、腔锥形感受器、Bohm氏鬃毛、鳞形感受器、叉形感受器和栓锥形感受器。鳞形感受器和叉形感受器只在雌蛾触角中发现,其它6种感受器在雌雄两性触角上的形态上没有明显的区别,但在数量和分布上有所差异。本研究为雌雄触角形态的二型性提供了超微结构水平上的证据。毛型感受器的数量在雌雄个体差异非常明显,这可能是茶刺蛾雌雄个体对茶树相关的挥发物的电生理反应的差异性的原因。更多还原

【Abstract】 The tea slug moth, Iragoides fasciata Moore (Lepidoptera:Limacodidae), which can break out under certain conditions, is one of the major insect pests of tea (Camellia sinensis L.(Ericales:Theaceae)). It not only causes reduction of tea output, and even result in death of tea plant, but also seriously hampers field operations of tea farmers. Currently, the control of tea slug moth mainly rely on chemical control, In view of the negative impact of chemical pesticides, new control technologies of other insect pest based on researches on chemical ecology have been developed in recent years, and more and more scientists pay attention on it.C. palpis Chao (Diptera:Tachinidae), a newly discovered parasitic natural enemy based on our field and laboratory observation is an important parasitic natural enemy of tea slug moth.Here, Chemical communications among tea plant, tea slug moth, Chaetexorista palpis Chao were investigated to provide a theoretical basis for the control of tea slug moth.Observed in the tea garden, we found that the number of C. palpis in the tea plantations where tea plants were damaged by tea slug moth was significantly more than those undamaged. We speculate that tea plant would release specific signal substances which play a key role in host location (especially long distance) by C. palpis. In order to confirm this conjecture, the effect of the damaging of tea slug moth on the volatile organic compounds (VOCs) of tea plant was studied. VOCs from the undamaged and damaged tea plants were collected by simultaneous distillation extraction and dynamic headspace, then analyzed by gas chromatography/mass spectrometry (GC-MS). The results of the foraier showed that a total of sixty-three components, mainly esters, alcohols, hydrocarbons, ketones, heterocyclic compounds, aldehydes, organic acids and ethers were identified in the undamaged twigs and leaves, and the relative content of hydrocarbons was19.05%, while that from the damaged ones increased to26.79%, and the relative content of cis-nerolidol, cedar alcohol, dibutyl phthalate and phthalic acid was significantly increased. Furthermore, thirty-two new compounds were identified in the damaged ones, including ten esters, five alcohols, five olefins, four heterocyclics, three aromatic hydrocarbons, one alkane, one ketone and one aldehyde. The latter results indicated that a total of seventy-four components were identified in the undamaged twigs and leaves, and the composition of volatile compounds was similar to the former. Compared with the undamaged twigs and leaves, the number and relative content of ethers, aldehydes, and hydrocarbons changed evidently, while those of alcohols, heterocyclic compounds, ethers and organic acid compounds had little change. After damage, the relative content of4-cymene, pinene,1-ethyl-2,4-dimethylphenoxy,4-ethyltoluene, toluene-ethyl-6-methyl-heptene[5]ketone[2] and1,2,4-trimethylbenzene increased significantly, fifty-four new compounds were founded in the damaged ones, including of fourteen alkenes, twelve aromatic hydrocarbons, eight esters, eight alkanes, five ketones, three alcohols, two aldehydes, one heterocyclic and one organic acid. It is worth noting that the number and relative content of terpenoids significantly changed, suggesting that these compounds maybe play an important role on the host finding by C. palpis.The results can lay a foundation for screening infochemicals which can be used as a lure for natural enemies of insects and applied to control I.fasciata MooreIn order to screen attractants for tea slug moth and C. palpis, Electroantennogram responses to a wide range of plant volatile compounds that have been identified in tea plants were recorded from males and females of the tea slug moth and C. palpis. The responses to26compounds, belonging to several chemical classes, and two mixtures were evaluated for tea slug moth, while27compounds for C. palpis. The results showed that most of the compounds can elicit significant electrophysiological responses in both tea slug moth and C. palpis. There were significant different electroantennogram responses to the different chemicals, different types of compounds,as well as significantly different responses according to gender in these two species. In general, the antennae of males of tea slug moth were more sensitive, and responded more strongly, to most of the compounds, while it was just the reverse in C. palpis, Responses to sesquiterpenoids were lower in both males and females of tea slug moth. Dose-dependent response studies indicated differences in response between genders and concentrations, suggesting the existence of sexual dimorphism in tea slug moth. In C. palpis, females responed more strongly to cis-3-hexene-1-alcohol, while males to cis-3-hexenyl acetate. Compounds belonging to green leaf volatiles class elicited significantly greater responses in both males and females in tea slug moth and C. palpis. we speculated that they might be important clues in host-plant selection by this oligophagous species and its parasitic natural enemy.In order to explain the differences of electrophysioiogical responses of the male and female of tea slug moth to some plant volatiles associated with tea, the antenna and antennal sensilla of tea slug moth were investigated by scanning electron microscopy. Eight types of antennal sensilla were found in the antenna: sensilla trichodea(ST), sensilla basiconica(SB), sensilla chaetica (SC), sensilla coeloconica (SCo), bohm bristles (BB), sensilla squamiformiaa (SS), sensilla furcatea(SF), sensilla styloconica(SST). Two types of antennal sensilla,sensilla squamiformiaa and sensilla furcatea were only found in female.There were no obvious sexual differences in sensillum morphology for the other six types of antennal sensilla, but a certain differences in distribution and quantity for these types. This study provided ultrastructural evidence for the sexual morphological dimorphism of the antenna. Obvious differences in the number of sensilla chaetica between male and female may be serve as the explanation for the differences of electrophysiological responses of the male and female of tea slug moth to some plant volatiles associated with tea.更多还原