稻飞虱生理发育与迁飞行为的磁响应机制研究

The geomagnetic field can avoid life on earth from the effects of cosmic rays' radiation; simultaneously, it also has an important role on the survival, growth and development of livings and their orientation behavior. In general, orientation behavior of agricultural migratory pests during the long-distance migration is one of the research focuses of insect behavior and pest forecast. And the magnetic developmental biology and migratory behavior of insect pests can be further studied and improved through to study the effects of magnetic fields (MFs) on the growth, development, reproduction and migratory behavior, and to clarify the mechanisms of magnetic response in physiologic development and migratory behavior of migratory insects, which is in turn to service for the prediction and forecast of the occurrences of agricultural migratory pests. In this study, the key insect pests of rice planthoppers, brown planthopper (BPH) Nilaparvata lugens, white backed planthopper (WBPH) Sogatella furcifera and small brown planthopper (SBPH) Laodelphgax striatellus, which are typically night migratory insect pests, are used and three types of magnetic fields are controlled, that is, near-zero magnetic field (NZMF), deflecting magnetic fields (DMF) and gradient magnetic fields (GMF) with the earth magnetic field (EMF) as the control treatment. The objectives of this study are following as: Firstly, the effects of magnetic fields on growth, development and reproduction of N. lugens, S. furcifera and L. striatellus, and the molecular biological mechanisms regulated development physiology and reproduction are studied to improve and perfect the developmental biology of rice planthopper affected by magnetic fields. Secondly, the impacts of magnetic fields on the migratory behavior (including migrating ability, geomagnetic orientation and photoinduced migration rhythms etc.) and the molecular biological mechanisms regulated migration behavior are also researched to make clear the mechanisms of magnetic response in migration behavior of rice planthopper; and the geomagnetic orientation of rice planthopper is tested under DMF in contrast to EMF, and the photoinduced migration rhythms of rice planthopper are also studied using flight mills under MFs and hourly automatic light trap in field netting. Finally, it is clear that this project carrying out can improve and perfect the developmental biology and migration behavior of rice planthopper, and service for the prediction and forecast of the occurrences of N. lugens, S. furcifera and L. striatellus.

地磁场除可避免地球生命受宇宙射线辐射影响外，还对地球生物生存与定向行为有重要作用。长期以来，农业迁飞性害虫远距离迁飞定向研究一直是昆虫行为学和害虫预测预报研究的重点。明确磁场变化对迁飞性害虫生长发育与繁殖及其迁飞行为影响的生物学效应，阐明其生理发育与迁飞行为的磁响应机制，有助于完善昆虫磁发育生物学与迁飞行为学，并为害虫预测预报服务。本研究以水稻重大迁飞性害虫褐飞虱、白背飞虱和灰飞虱为研究对象，开展零磁场、偏转磁场和梯度磁场对稻飞虱生长发育与繁殖的影响及其发育与繁殖调控的分子生物学机理研究；其次，开展磁场变化对稻飞虱迁飞行为的影响及其行为调控的分子生物学机理研究，并开展偏转磁场下稻飞虱迁飞种群地磁定向行为验证以及光诱导的稻飞虱种群迁飞行为节律研究，以明确稻飞虱迁飞行为的磁响应机制。最终，完善稻飞虱磁发育生物学和迁飞行为学研究，并服务于生产中稻飞虱迁飞种群预测预报及其稻田防控。

地磁场不是恒定不变的，而是随时间和空间时刻变化。迁飞昆虫多可进行远距离迁飞，其迁出与迁入地间必然存在磁场变化。明确磁场变化对迁飞性害虫生长发育与繁殖及其迁飞行为影响的生物学效应，阐明其生理发育与迁飞行为的磁响应机制，有助于完善昆虫磁发育生物学与迁飞行为学，并为迁飞害虫预测预报服务。本项目以稻飞虱为模式昆虫，人工模拟磁场强度变化：首先，开展了稻飞虱生理发育和繁殖对磁场强度变化的磁响应表型研究，研究发现三种稻飞虱生理发育和繁殖对磁场变化的响应存在种的特异性，但总体表现为磁场强度减弱引起若虫发育变缓，成虫体重降低，寿命延长和生殖力下降；其次，开展了稻飞虱迁飞行为对磁场变化的磁响应表型研究，研究发现磁场强度减弱可导致白背飞虱和褐飞虱短翅型比例升高，长翅成虫趋光性总体增强，同时改变了长翅成虫的飞行策略，即通过影响飞行速度和飞行时间最终影响稻飞虱飞行距离；之后，基于“磁颗粒介导的磁感受”假说，对褐飞虱体内磁性物质进行了定性、定量、定位探究，首次证实褐飞虱腹部存在主要成分为Fe3O4的内源性纳米磁颗粒（粒径50~450 nm），且长翅型成虫体内含量多于短翅型，暗示该磁颗粒或与褐飞虱迁飞定向有关，为该假说提供了重要的实验和物质基础；最后，基于“隐花色素介导的基于自由基对的磁感受”假说，通过检测与磁响应表型对应的磁响应关键基因的转录表达谱及进行RNAi功能验证，发现磁感受关键基因隐花色素（CRY1，CRY2）及MagR，联同保幼激素信号通路、蜕皮激素信号通路和激脂激素信号通路关键基因调控了稻飞虱生理发育和繁殖以及迁飞行为的磁响应过程，基于此，本团队首次提出了“基于隐花色素介导的激素信号转导的磁响应”机理。本项目的完成一方面促进了“基于磁颗粒的磁感受”和“隐花色素介导的基于自由基对的磁感受”理论的发展；另一方面，将推动迁飞昆虫发育磁生物学、迁飞磁生物学的相关系统研究，有望应用于迁飞害虫田间为害的预测预报。