不同危害状态下寄主萜烯挥发物含量的变化及松墨天牛对其组分的触角电位反应

用气相色谱-质谱（GC-MS）联用法对5种生理状态（健康、人为物理损伤、饵木、取食和产卵）的马尾松Pinus massoniana和取食危害状态的雪松Cedrus deodara的萜烯进行分析。研究结果显示，5种生理状态下，α-蒎烯在萜烯组分中均占有最高比例。健康状态下马尾松树干和树枝中的萜烯组分不同且含量有显著差异。随着饵木的衰弱进程，α-蒎烯的相对含量显著减少，β-蒎烯的含量显著增加，我们推测，α-蒎烯与β-蒎烯的相对比例越小则寄主树势衰弱的程度越深，其两者比例的变化是马尾松寄主树势衰弱程度变化的一个重要信号。人为物理损伤的马尾松树干与树枝的α-蒎烯、β-蒎烯和β-水芹烯含量差异显著。不同产卵危害程度的马尾松树干萜烯类组分不同，同一产卵危害程度的马尾松树干上部和下部的多数萜烯组分相对含量差异显著，但变化无明显规律。取食危害状态下马尾松和雪松萜烯种类不同且含量差异显著。重度产卵危害马尾松树干与取食危害树枝萜烯中，α-蒎烯、β-蒎烯、柠檬烯和β-水芹烯相对含量差异显著。第13天的饵木与人为物理损伤的马尾松树干的萜烯中，饵木的β-蒎烯和柠檬烯相对百分含量均比人为物理损伤状态的高，而α-蒎烯则相反。α-蒎烯和β-蒎烯在取食危害树枝中的含量显著高于健康树枝，而β-月桂烯、β水芹烯和反式石竹烯在健康状态树枝中的含量显著高于取食危害树枝。除了α-蒎烯和β蒎烯，健康状态与产卵危害状态的马尾松树干萜烯相对含量大都差异显著。α-蒎烯，β-蒎烯和β-水芹烯在人为物理损伤与虫害状态的马尾松树干及树枝中含量差异较大。总之，α-蒎烯、β-蒎烯和β-水芹烯很可能是影响和调节松墨天牛取食和产卵行为最为重要的信号物质。松墨天牛Monochamus alternatus Hope对寄主萜烯的触角电位（EAG）表明，该天牛对β-蒎烯的EAG活性高于其他萜烯，乙醇也能引起较高的EAG反应活性，但总体上对单一萜烯的EAG反应活性不强，且存在雌雄差异。

Changes in contents of host volatile terpenes under different damaged states and electroantennogram response of Monochamus alternatus Hope to these volatiles

Based on the analysis of terpene samples in five physiological states of host trees by gas chromatography-mass spectrum, α-pinene has the largest proportion in all states. There are large variations in terpene compositions and their relative contents in stem and branch of healthy Pinus massoniana. With the decline of host pine health, the relative contents of α-pinene significantly decrease and the relative contents of β-pinene significantly increase in stems or branches of baited tree. We conclude that the lower ratio of α-pinene and β-pinene indicates the more declining host health. The contents of α-pinene, β-pinene and β-phellandrene were significantly different between P. massoniana stem and branch in physically damaged states. P. massoniana also has a distinctive terpene composition on the trees damaged by oviposition as well as the up and down part of the stem. In feeding damaged state, there are large variations in terpene compositions and their relative contents between P. massoniana and Cedrus deodara. The relative contents of α-pinene，β-pinene and β-phellandrene are significantly different in heavily oviposited stem and feeding-damaged branch. The contents of β-pinene and limonene in baited stem after 13 days are higher than those in physically damaged stem after 13 days, but the content of α-pinene varied contrarily. The relative contents of α-pinene and β-pinene in feeding-damaged branch are significantly higher than those in heathy branch, and β-mercene,β-phellandrene and trans-caryophyllene in healthy branch are significantly higher that those in feeding-damaged branch. The relative contents of terpene compositions are significantly different between healthy stem and oviposited stem, except for α-pinene and β-pinene. There are large variations in the relative contents of α-pinene, β-pinene and β-phellandrene in stem or branch between physically damaged, oviposited and feeding-damaged states. In conclusion, α-pinene, β-pinene and β-phellandrene maybe play important roles in regulating the feeding and ovipositing behaviours of Monochamus alternatus Hope. M. alternatus showed a moderate electroantennogram (EAG) response to many volatile terpenes, but there is a significant sexual difference of the relative EAG responses between male and female. The highest EAG response was elicited by β-pinene. 