宁夏枸杞-枸杞红瘿蚊-齿腿长尾小蜂三级营养间的化学通讯与识别机制研究

Jaapiella sp. is the most serious pest of wolfberry Lycium barbarum, known as “Cancer of the wolfberry”. It has a narrow range of host plants and mainly feeds on the plants of L. barbarum. In China, the adults of Jaapiella sp. solely oviposit and feed on particular period flower buds of the wolfberry, causing severe economic losses. Monodontomerus sp. is the specific natural enemies-parasitoids of Jaapiella sp., only selecting the special period galls, which can effectively control the population of Jaapiella sp. in the field. We conclude that the specific oviposition selectivity of Jaapiella sp. and its parasitoids may be related to the specific morphological structure and complicated chemical information of the hosts. Our previous research found that odor mixtures derived from the flower buds and galls of L. barbarum could attract Jaapiella sp. and its parasitoids for locating hosts accurately. In the project, host selection and response mechanism of Jaapiella sp. and Monodontomerus sp. will be elucidated thoroughly. Volatiles from the flower buds and galls of L. barbarum will be collected, identified and quantified. And the olfactory recognition mechanism of Jaapiella sp. and Monodontomerus sp. to these chemical signals will be studied through morphology, nutrition, electrophysiology, behavior and chemical communication. In total, the objective of the present project is to reveal the outbreak mechanism of Jaapiella sp., explore the ecological effects of chemical signal substances in L. barbarum communities, and finally provide a theoretical basis for controlling the pests based on the natural enemies resourse.

枸杞红瘿蚊是宁夏枸杞重发频发的主要成灾害虫，号称“枸杞癌症”。该虫对宁夏枸杞的寄主选择非常专一，成虫仅选择特定阶段的枸杞花蕾产卵为害；齿腿长尾小蜂是枸杞红瘿蚊的专食寄生性天敌，雌蜂仅选择特定龄期的虫瘿产卵寄生，对枸杞红瘿蚊的种群数量具有显著抑制作用。枸杞红瘿蚊及其天敌对寄主特定阶段的产卵选择性，推测与其寄主特定形态结构及复杂的化学信息物质有关。前期研究发现，枸杞花蕾与虫瘿挥发物均可分别诱导枸杞红瘿蚊和齿腿长尾小蜂成虫准确定位寄主。鉴于此，本项目以宁夏枸杞、枸杞红瘿蚊及其天敌齿腿长尾小蜂为研究对象，围绕枸杞红瘿蚊和齿腿长尾小蜂寄生过程中花蕾与虫瘿的应答反应，从形态学、营养学、电生理学、行为学和信号识别入手，深入剖析三者之间信息识别的物质基础和作用机制，揭示枸杞红瘿蚊在宁夏枸杞上的暴发成灾机制，探索化学信号物质在枸杞群落中所发挥的生态效应，为利用天敌资源科学管理枸杞红瘿蚊提供理论依据。

枸杞红瘿蚊是宁夏枸杞重发频发的成灾害虫，号称“枸杞癌症”。齿腿长尾小蜂是枸杞红瘿蚊的专食寄生性天敌，对其种群数量具有抑制作用。为了揭示宁夏枸杞-枸杞红瘿蚊-齿腿长尾小蜂三级营养间的化学通讯关系与识别机制，本项目以宁夏枸杞、枸杞红瘿蚊及齿腿长尾小蜂为研究对象，从害虫与天敌的基础生物学、化学信息交流与调控方面展开研究。首次鉴定并命名枸杞红瘿蚊为枸杞花桥瘿蚊Gephyraulus lycantha Jiao & Kolesik，为Gephyraulus属新种，从昆虫分类学角度科学地纠正和统一了长期以来人们对枸杞红瘿蚊种名的错误认识；首次发现、鉴定枸杞红瘿蚊的寄生性天敌新种——枸杞红瘿蚊拟长尾小蜂Pseudotorymus jaapiellae Yang et Chen，为枸杞红瘿蚊的天敌防治提供技术支撑；摸清了枸杞红瘿蚊基础生物学，阐明了暴发成灾机制是科学防治的关键，其成虫的羽化-交尾-产卵非常集中、迅速，不到一日便可完成生殖繁衍，且该虫的暴露期仅在成虫期，寿命极短，仅为1-2天，因此田间一旦发现成虫，大部分已完成交尾和产卵，并随即死亡，导致使用化学农药等常规措施不能及时有效防治，这是枸杞红瘿蚊极易暴发成灾、又极难防控的主要原因之一；基于信息化学物质的害虫管理策略，从枸杞-枸杞红瘿蚊二级营养系统中鉴定出对枸杞红瘿蚊具有生物活性的信息化学物质3-蒈烯、莰烯、d-柠檬烯、萜品油烯、月桂烯，配制的引诱剂在田间对枸杞红瘿蚊进行准确监测和行为调控，阐明了枸杞红瘿蚊与枸杞花蕾之间的嗅觉识别及应答机制；揭示了枸杞红瘿蚊拟长尾小蜂能通过对枸杞不同发育阶段受害虫瘿的特异性挥发物进行寄主识别，从而定位寄主，实现对枸杞红瘿蚊的种群调控。研究结果为阐明宁夏枸杞-枸杞红瘿蚊-齿腿长尾小蜂三级营养间的化学通讯关系与识别机制，利用信息化学物质及天敌昆虫防治枸杞红瘿蚊提供技术支撑，具有重要的理论和应用价值。