烟粉虱对其两种优势寄生蜂种间竞争的调节和响应机制

Usually, the biological control effect is hard to sustain when parasitoid released singly. To screen and apply more effective parasitoids combination and make a sustainable biological control strategy of Bemisia tabaci biotype Q, we focus on two promising parasitoids of B. tabaci, Eretmocerus hayati and Encarsia sophia to investigate effects of host availability on the interspecific interactions of these two parasitoids. Three experiments will be conducted via methods of entomological physiology, ethology, immunology and population ecology: (1) effects of host availability on host discrimination, host handling strategies and competition mechanisms of two parasitoid females; (2) effects of host availability on larval competition ability and mechanisms as well as offspring adaptability of two parasitoids; and (3) immune reactions of B. tabaci induced by multiparasitism of parasitoids and feedbacks of these reactions on interspecific competition of parasitoids. The completion of this project will answer how host resource regulates interspecific competition and population dynamics of parasitoids. It will provide new insights in understanding the theory of niche complementarity and synergy effects on pest control and benefit the establishment of sustainable and safe management system and techniques of B. tabaci biotype Q.

针对烟粉虱寄生蜂单种释放时控效难以持续的现状，为筛选和利用更高效的天敌组合，制定Q型烟粉虱持续有效的生防策略，本项目围绕寄主资源可利用性影响寄生蜂种间竞争互作这一科学问题，以海氏桨角蚜小蜂和浅黄恩蚜小蜂为对象，采用昆虫生理学、行为学、免疫学及种群生态学等技术方法，重点研究：（1）寄主资源可利用性对两种寄生蜂雌成蜂的寄主处理策略、识别能力和种间竞争行为的影响；（2）寄主资源可利用性对两种寄生蜂幼虫种间竞争能力、竞争机制及子代适应性的影响；（3）寄主烟粉虱对两种寄生蜂种间竞争行为（多寄生）的免疫应答反应及这些反应对寄生蜂种间竞争的反馈调节作用。通过上述研究，以期阐明寄主资源调节两种寄生蜂种间竞争和种群变化的机制，指导不同寄主资源条件下寄生蜂释放策略的制定，从而丰富昆虫寄生蜂的“生态位互补与协同控害”理论，为构建Q型烟粉虱持续治理对策和技术体系提供理论依据。

针对烟粉虱寄生蜂单种释放时控效难以持续的现状，为筛选和利用更高效的天敌组合，本项目以海氏桨角蚜小蜂和浅黄恩蚜小蜂为对象，重点研究了：两种寄生蜂雌成蜂的寄主处理策略、识别能力和种间竞争行为，寄生蜂幼虫种间竞争能力和竞争机制，适生性的差异以及烟粉虱对寄生蜂寄生行为的免疫应答反应。主要结果包括：（1）明确了不同类型的寄主对浅黄恩蚜小蜂和海氏桨角蚜小蜂的寄主处理行为、寄生/取食权衡和种间寄主识别的影响：无论是对健康寄主还是对异种已寄生寄主，浅黄恩蚜小蜂对寄主的取食率都显著高于海氏桨角蚜小蜂，说明浅黄恩蚜小蜂倾向于取食致死寄主而海氏桨角蚜小蜂倾向于寄生致死寄主；浅黄恩蚜小蜂倾向于接受异种已寄生寄主进行产卵寄生，而海氏桨角蚜小蜂倾向于拒绝在异种已寄生寄主上产卵寄生，说明相对于浅黄恩蚜小蜂来说，海氏桨角蚜小蜂具有较强的种间识别能力。（2）明确了浅黄恩蚜小蜂和海氏桨角蚜小蜂幼虫的种间竞争能力和机制：浅黄恩蚜小蜂幼虫在多数竞争中取胜，较短的卵期发育历期和整个幼虫期营内寄生是浅黄恩蚜小蜂幼虫取胜的主要原因。（3）采用特定年龄-阶段两性生命表对浅黄恩蚜小蜂和海氏桨角蚜小蜂在最适条件下的生活史特征进行了分析比较，明确了两种寄生蜂的适应性差异：海氏桨角蚜小蜂的单雌产卵量（211.4粒）和每日最大产卵量（54粒）显著高于浅黄恩蚜小蜂（101.6粒和22粒），但后者的净取食率（84.1头/雌）和对寄主的周限致死率（0.6713）显著高于前者（17.6头/雌和0.3652）。（4）明确了海氏桨角蚜小蜂寄生前后，烟粉虱若虫体内营养代谢和次生内共生菌Hamiltonella相对含量的变化。上述研究阐明了寄主资源调节两种寄生蜂种间竞争和种群变化的机制，可指导不同寄主资源条件下寄生蜂释放策略的制定，为构建Q型烟粉虱持续治理技术体系提供理论依据。