藏东南主要针叶林种实害虫及其寄主选择机制研究

The coniferous forest was the main type of subalpine virgin forest in southeast Tibet. The research methods were the general investigation, the regular fixed-point investigation, the indoor-rearing of seed pests, the chemical experiment and so on in the project. The method characteristcs were the combination of macroscopic and microscopic, the simultioneous usage of traditional method and medern technology. The species, distribution and harm of main coniferous seed pests will be investegated in the study by these methods in southeast Tibet, these coniferous species were Pinus densata, Abies georgei var.smithii, and Picea likiangensis var. linzhiensis. The new species of seed pests would be found.The importance of seed pests were evaluated according to economics principle of seed pests. The important species of seed pests were determined by investigation and analysis, which has seriously affected the carrying out of natural forest protection project and national ecological security barrier in Tibet plateau. The project would study the biological and ecological characteristics including morphology, biology, ecology and chemical ecology, pest ecolgy still included population structure and quantitative dynmaics, population spatial distribution, population sampling technique and predication. The research targets of project were ascertaining the biological and ecological characteristics of seed pests, revealing the relationship between occurrence and environment of seed pests, probing into host selected mechanism of main coniferous seed pests. The research would reveal the mechanism of chemical ecology between seed pests and host, and provide new biological control approach of these pests. The research results had significance for enriching forest entomology, pushed on the research progress of coniferous seed pests in China, promoted the smooth implementation of national ecological security barrier in Tibet plateau.

针叶林是藏东南亚高山原始林的主要类型，本研究采用普遍调查、定期定点调查、室内饲养、化学试验等方法，注重宏观与微观手段相结合，传统方法与现代技术并用，对藏东南主要针叶林（高山松、急尖长苞冷杉、林芝云杉）种实害虫进行研究，查明该区主要针叶林种实害虫的种类、分布及危害，可能发现新的种实害虫，根据害虫经济学原理进行重要性评估，确定当前影响天然林保护工程和在西藏生态安全屏障构建中的重要害虫种类。对重要种类的形态学、生物学、生态学（种群动态、空间分布型、抽样技术、预测预报等）及化学生态进行研究，弄清藏东南主要针叶林重要种实害虫的生物学、生态学特性，发生与环境的关系，探讨重要种实害虫对寄主的选择机制。该研究有助于揭示重要种实害虫对寄主危害的化学生态机理，为这些害虫的防治开辟新的生物防治途径，对丰富中国森林昆虫学具有重要意义，可以促进我国针叶树种实害虫研究的进展和推动西藏高原国家生态安全屏障的顺利实施。

项目研究藏东南主要针叶林种实害虫种类；重要种的生物学、生态学特性；重要种实害虫对寄主挥发物的选择性。项目主要研究结果：藏东南高山松林球果害虫为赤松梢斑螟 Dioryctria sylvestrella，林芝云杉林球果害虫为冷杉梢斑螟D. abietella，急尖长苞冷杉林球果害虫为球果螟D. sp.、球果花蝇Lasiomma sp.和大痣小蜂Megastigmus sp.。冷杉梢斑螟在林芝地区1年发生1代，以幼虫为害林芝云杉球果果轴、种鳞和种子，且以幼虫在球果内越冬，有滞育现象，无转移危害现象，翌年6月中旬开始羽化为成虫，一直持续到8月上旬，成虫期5-8 d，卵期9-14 d，幼虫期近10.5个月，蛹期25-36 d。赤松梢斑螟在藏东南1年发生1代，以幼虫在高山松当年生球果内越冬，成虫期8 d左右，卵期10 d左右，幼虫期300 d左右，蛹期40 d左右。幼虫孵化始于6月下旬，11月上旬幼虫陆续进入越冬状，翌年3月下旬幼虫开始活动，5月上旬开始化蛹，成虫6月中旬开始羽化，羽化盛期为6月下旬。冷杉梢斑螟幼虫的各聚集度指标均表明其在林芝云杉林的空间分布格局为聚集分布；各回归模型以 La-m 回归模型的拟和效果最好。冷杉梢斑螟幼虫无论是越冬前还是越冬后，都明显趋向和选择林芝云杉虫害球果，成虫选择去年生林芝云杉虫害球果和当年生健康球果产卵，而不选择去年生健康果和枝梢产卵，GC-MS结果表明：冷杉梢斑螟幼虫期和成虫期，健康球果、虫害果及枝梢挥发性萜类组分显著不同，虽然同一时期的虫害果和健康果挥发性主组分一致，但球果受害后，各组分含量明显变化，幼虫长期在虫害球果中生活，已经与虫害球果相适应。冷杉梢斑螟对林芝云杉球果挥发物的触角电位及行为反应研究表明：未交配2日龄雌雄成虫和已交配雌虫三种状态的冷杉梢斑螟对α-蒎烯、β-蒎烯、(1S)-(-)-β-蒎烯、柠檬烯、反式石竹烯、月桂烯均有反应。Y型嗅觉仪生测结果表明：α-蒎烯、β-蒎烯、柠檬烯是球果挥发物的基础组分，反式石竹烯在球果挥发物组分中引诱成虫有增效作用，月桂烯对冷杉梢斑螟有驱避作用。