舞毒蛾卵平腹小蜂打斗行为的生理机制

In most animal species, aggressive behaviour is a complex social behavior for the acquisition of resources such as food, territory and mates. As a result, aggressive behavior has an important impact on animals in terms of the survival and reproduction. Therefore, investigating animal's aggressive behaviour and its mechanism will have theoretical value and significance for explaining mechanisms of animal behavior ecology, developmental biology and population evolution. Anastatus disparis (Ruschka) (Hymenoptera: Eupelmidae) is a quasi-gregarious egg parasitoid of several noxious species of Lepidoptera that are primarily forest pests, including the Lymantria dispar, Malacosoma neustria, Odonestis pruni. In the previous study, A. disparis male showed the aggressive behaviour for mate and the characteristics of fighting was preliminarily investigated. By means of entomological behavior, chemical ecology, insect physiology and molecular biology, this study mainly focus on aggressive behaviour affected by the physiological aspects including the sex pheromone and the neurotransmitter dopamine, And, the effected of male fitness influenced by aggressive behaviour was exploited as well. Our research aims to clarify the physiological mechanism regulating aggressive behaviour, theoretically, which can either interpreting the mechanism of reproductive strategy and ecological evolution in parasitoid wasps, and enrich the theory of ‘Local mate competition’. Besides, this study will provide a theoretical basis for large-scale reproduction and utilization in biological control agent.

打斗行为是动物界中广泛存在的社会性行为，因竞争配偶、食物、领地等资源的打斗行为影响动物的生存和繁衍，研究动物的打斗行为及其机制，阐释动物的行为生态学、发育生物学和种群演化机制具有重要的理论价值。申请人在前期研究中发现舞毒蛾卵平腹小蜂雄蜂为争夺配偶发生打斗行为，进而研究了相关行为特性。本项目拟利用昆虫行为学、化学生态学、昆虫生理学、分子生物学等方法，从调控打斗行为的生理学角度入手，开展①打斗行为对雄蜂种群适合度的影响；②雌蜂性信息素对雄蜂打斗行为的作用特点；③神经调控物质——多巴胺对雄蜂打斗行为的调控方式；④舞毒蛾卵平腹小蜂子代性别分配与打斗行为的关联性等研究，以期阐明舞毒蛾卵平腹小蜂雄蜂间打斗行为的生理学机制，解析准多寄生蜂打斗行为策略与性别分配机制，丰富和扩展“局部配偶竞争”理论，研究结果对舞毒蛾卵平腹小蜂的繁殖和利用具有实践指导意义。

本项目基于前期发现舞毒蛾卵平腹小蜂雄蜂间的打斗行为，为揭示雄蜂间打斗行为的生理机制，阐释打斗行为生态学和种群性别分配的关系，利用昆虫行为学、分析化学、化学生态学、种群生态学、分子生物学、生物信息学等技术和方法，系统研究了雄蜂日龄、密度、打斗经历、交配状态等因素对舞毒蛾卵平腹小蜂雄蜂间打斗行为的影响，探究了性信息素和多巴胺对雄蜂打斗行为的生理调控作用，解析了舞毒蛾卵平腹小蜂子代性别分配与打斗行为的关联性，取得的主要成果：（1）基于转录组测序数据，分析和注释了舞毒蛾卵平腹小蜂雌雄成虫性别偏向的差异表达基因及其功能，筛选出与生物学、寿命、生殖以及调控雄峰打斗行为生物胺相关的基因。（2）观察研究了个体经历、生理状态等对雄蜂打斗行为的影响，明确了受伤状态、交配经历、日龄显著影响的雄蜂打斗强度和频率，而亲缘关系对打斗行为无影响；明晰了打斗对雄蜂寿命和交配等种群适合度的不利影响。（3）发现雌蜂存在显著增强雄蜂间的打斗强度和频率，分离并鉴定了雌蜂的性信息素组分cis-9- Eicosen-1-ol；揭示了获得与雌蜂的交配权是激发舞毒蛾卵平腹小蜂雄性间打斗行为的根本动因。（4）鉴定了雄蜂多巴胺合成的限速酶—络氨酸-3-单氧化酶（tyrosine 3-monooxygenase, TH）基因及其日龄的表达量动态，进而利用ELISA方法测定不同日龄雄蜂体内多巴胺含量变化，分别证实了多巴胺调控舞毒蛾卵平腹小蜂雄蜂打斗行为的作用。（5）阐明了舞毒蛾卵平腹小蜂建群者数量与子代性比的关系并不符合局部配偶竞争理论（Local Mate Competition Theory，LMC）的预测结果；明确了高度偏雌性的性比并非因雄蜂间极端打斗行为强化局部配偶竞争压力所引起，而是由于寄主内子代幼虫因竞争使得更多雄虫死亡所导致。本项目的研究结果为深入探究舞毒蛾卵平腹小蜂生理调控打斗行为的分子机制奠定了基础，也为准多寄生蜂的行为生态学和种群进化理论的研究具有借鉴和参考价值。