秋季绿盲蝽末代成虫偏好选择枣树和葡萄树的化学通讯机制

In recent years, Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) has become a key insect pest of cotton (Gossypium hirsutum L.), Ziziphus jujube, Vitis vinifera and other crops in China. Previous field surveys found that last-generation A. lucorum adults preferred for Z. jujube and V. vinifera as overwintering host plants. In Y-tube olfactometer bioassays, the results indicated that last-generation A. lucorum adults significantly more preferred to the direction of the olfactometer where Z. jujube or V. vinifera plants were present compared to cotton plants in autumn. However, so far the underlying chemical communication mechanism of this host preference behavior of last-generation A. lucorum adults remains unclear. In the present study, by using the techniques and methods of behavioristics, electrophysiology and analytical chemistry, we firstly identified the active volatile components from Z. jujube and V. vinifera that elicited the electrophysiological responses of last-generation A. lucorum adults by means of gas chromatography-electroantennography (GC-EAD) combining with gas chromatography-mass spectrometer (GC-MS) and chemical standard sample. Also, we determined the electrophysiological and behavioral responses of last-generation A. lucorum adults to these active volatile components in the laboratory. Secondly, we compared the quantity difference of active volatile components among different periods (summer and autumn) of Z. jujube and V. vinifera, and examined the quantity of active volatile components emitted from cotton plants in autumn. Finally, we systematically investigated the trap effect of active volatile components with different combinations to last-generation A. lucorum adults in the laboratory and in the fields, and screened the optimal application technology of optimum formula of active volatile components. These findings contribute to shed light on the chemical communication mechanism between last-generation A. lucorum adults and its overwintering hosts of Z. jujube and V. vinifera, and provide groundwork for the development of environmentally sound and sustainable management tactics of this polyphagous mirid bug.

绿盲蝽寄主范围广，常年在不同农作物上转移危害，是棉花、枣、葡萄等上的一种重要害虫。前期调查发现，秋季绿盲蝽末代成虫偏好选择枣树和葡萄树进行产卵越冬；行为测定表明，嗅觉在这一行为过程中起着关键的作用。本项目拟采用行为学、电生理学以及分析化学等技术与方法，（1）分析鉴定秋季枣树和葡萄树挥发物组分中对绿盲蝽末代成虫具有明显电生理和行为活性的组分；（2）对比分析不同时期枣树和葡萄树以及秋季棉花挥发物中活性组分的含量；（3）研究筛选对绿盲蝽末代成虫诱捕效果较好的活性挥发物最佳配方及其配套使用技术。预期研究结果将阐明秋季绿盲蝽末代成虫与枣树和葡萄树之间的化学通讯机制，为开发绿盲蝽植物源引诱剂以及末代成虫绿色防控技术提供科学依据。

绿盲蝽成虫具有明显的季节性寄主转换习性，其中植物挥发物在其夏季选择开花植物的过程中起着关键的作用。秋季，绿盲蝽成虫偏好选择枣树和葡萄树进行产卵越冬。然而，是否植物挥发物调控着绿盲蝽成虫的这一寄主选择行为还未明确。本项目首先于2015-2016年的8月中旬与9月中旬分别调查了棉花、枣树和葡萄树上绿盲蝽成虫的种群数量，发现8月中旬棉花上绿盲蝽成虫的种群密度显著高于9月中旬，而枣树和葡萄树上的结果与之正好相反。然后利用Y型嗅觉仪于8月中旬与9月中旬分别测试了绿盲蝽成虫对棉花与枣树/葡萄树的趋性行为反应。结果表明，与枣树/葡萄树相比，8月中旬绿盲蝽雌雄成虫明显偏好棉花，而9月中旬的结果与之正好相反。利用GC-EAD联用系统筛选9月中旬枣树和葡萄树挥发物组分中引起绿盲蝽成虫明显电生理反应的活性物质峰。GC-MS分析鉴定发现枣树中引起绿盲蝽成虫明显电生理反应的活性物质峰分别是丙烯酸丁酯、丙酸丁酯和丁酸丁酯，而葡萄中仅是丙烯酸丁酯和丁酸丁酯。最后，通过外标法利用GC-MS检测了8月中旬与9月中旬棉花与枣树/葡萄树挥发物组分中活性挥发物的含量。结果显示，与8月中旬相比，枣树/葡萄树挥发物组分中活性物质的含量进入9月中旬明显增加，而棉花挥发物组分中活性物质的含量却大大减少。因此，9月中旬活性挥发物含量的升高调控着秋季绿盲蝽成虫对枣树与葡萄树的寄主选择偏好行为。以上结果为理解多食性绿盲蝽的寄主选择与偏好行为提供重要的理论基础。