自复寄生蜂浅黄恩蚜小蜂性别分配的行为调控机理

The introduction of facultative hyperparasitoid in biological control applications has long been controversial, since the reproducing of male offspring at the expense of a homogeneous or heterogeneous immature parasitoid. In this proposed project, we will target on one introduced parasitoid of Bemisia tabaci, Encarsia sophia. To better understand the sex ratio adjustment mechanism of hyperparasitoid, four experiments will be conducted. Firstly, the strategy of multiple mating of both male and female adults, as well as the reproduction profits of multiple mating will be examined. Secondly, the interaction among ovipositing founders and the following effects on sex ratio adjustment will be explored. Thirdly, the feedback of sex ratio on the host resources availability with the composition and density of primary and secondary hosts will be measured. Finally, the sex allocation model of hyperparasitoid will be established and analyzed. The implement of this present project will contribute to a better understanding on the trade-off of multiple mating strategy, local resource competition and host resource utilization mechanism; will also develop sex allocation theories of hyparasitoid such as Local Mate Competition. Moreover, it will provide clear clues to guide the mass raring and releasing strategies of Encarsia sophia, in the sustainable biological control management of Bemisia tabaci.

针对兼性自复寄生蜂繁殖雄性后代以牺牲本种或异种寄生蜂幼虫为代价所引发的生防应用权衡难题，围绕自复寄生蜂如何调节后代性比的科学问题，采用繁殖生物学、昆虫行为学等的技术与方法，以Q烟粉虱优势寄生蜂浅黄恩蚜小蜂为对象，重点研究：雌、雄蜂多次交配的行为决策及其繁殖效益；建群产卵雌蜂个体间的相互感知及其对后代性比的调控；初级/次级寄主资源条件的对寄生蜂后代性比的影响；并构建自复寄生蜂性别分配机制的数学模型。预期结果将揭示浅黄恩蚜小蜂性别分配的多次交配策略、建群蜂群体的资源竞争以及寄主资源可用性的权衡机制，发展和丰富自复寄生蜂性别分配及进化的局部配偶竞争等相关理论，指导烟粉虱优势寄生蜂规模化饲养和释放策略的制定，为生物防治实践中权衡应用自复寄生的浅黄恩蚜小蜂防治Q烟粉虱提供理论依据。

兼性自复寄生蜂产生雄性后代以牺牲本种或异种寄生蜂幼虫为代价，亲代雌性必须交配后才能产下受精卵寄生一级寄主（即靶标昆虫）以获得二倍体雌性后代。本项目针对这一繁殖特性所引发的兼性自复寄生蜂的性别分配策略及其引发的在生防应用中的权衡难题，以Q烟粉虱优势寄生蜂浅黄恩蚜小蜂为研究对象，围绕自复寄生蜂如何调节后代性比的科学问题，采用繁殖生物学、昆虫行为学、种群生态学的研究手段，重点从浅黄恩蚜小蜂单次交配后的产雌产雄规律、多次交配行为特性及其产生的繁殖效益、初/次级寄主资源条件对浅黄恩蚜小蜂后代性比的影响以及浅黄恩蚜小蜂在烟粉虱生物防治中的应用技术等四方面开展研究。主要结果包括：（1）浅黄恩蚜小蜂雌蜂无产卵前期和产卵后期，雌蜂单次交配后受精囊内储备的精子不足以保证其在整个产卵期内都能够产下雌性后代。（2）雌、雄蜂均可进行多次交配，雄蜂首次交配后两小时内的再次交配率为76.7%；雌蜂的多次交配行为与产卵经历有关，雌蜂仅在有产卵寄生行为后才可接受再次交配，首次交配后24 h内的再次交配成功率达72.8%；雄蜂的再次交配对自身寿命及配偶寄生量无显著影响，而雌蜂多次交配可提高其繁殖力；雄蜂更倾向于选择无交配经历雌蜂交配，而处女蜂更多的选择接受有交配经历的雄蜂进行交配，雄蜂的多次交配几率增大。（3）浅黄恩蚜小蜂具备调节自身后代性比的能力，且寄主密度和寄主比例均会对该蜂的后代性比产生影响；在寄主密度较低时，雌蜂的后代性比依据初级寄主与次级寄主的相对丰度进行调节；随寄主密度的增加，后代性比趋向于1:1。（4）浅黄恩蚜小蜂与海氏桨角蚜小蜂以1:3的密度混合释放比单种释放具有更好的控制效果，田间以1/10的益害比、连续3周释放寄生蜂能获得较好的烟粉虱防治效果。在本项目资助下，已发表论文9篇，其中SCI源论文6篇；授权专利4项；成果获教育部科学进步二等奖和青岛市科学进步一等奖各1项。