栎黄枯叶蛾幼虫寄主选择机制的光谱学研究

摘要

Trabala vishnou gigantina Yang (Lepidoptera: Lasiocampidae) is a polyphagou s forestry pest whose periodic breaking out results in great economic damage inc luding total crop failure to forestry and fruit production in China.In this stu dy,in order to improve the understanding of the host plant selection mechanism of T.vishnou gigantina larvae,locust,caragana,willow,poplar,ap ricot and sea-buckthorn were used as potential host plants for the test.Twoway choice experiment method was used to study the T.vishnou gigantina Yang fe eding preferences of the six kinds of plants.Moreover,the chemical component and physical structure of six plants were analyzed with Fourier transform infra re d (FTIR) spectroscopy and X-ray diffraction (XRD).Among the six plants,T.vi shnou gigantina larvae showed a strong preference for sea-buckthorn,followe d by,apricot,willow,poplar,locust,and caragana.The FTIR analysis dis played that those six plants presented similar characteristic on absorption peak position,peak amount,and shape.The targets (1 154/1 733,1 154/898) by F TIR showed that lipids and polysaccharide were major nutriments to affect the ho st plant selection of T.vishnou gigantina larvae.The XRD results showed that crystallinity index (CrI) also could affect the host plant selection of T.vishnou gigantina larvae.In this research,spectroscopy technology was f irstly applied to the study of interactive relationship between insect and host,which would blaze a trail for intensive study of host plant selection mechanis m of insect at molecular level.%栎黄枯叶蛾(Trabala vishnou gigantina Yang)是一种多寄主林业害虫,在我国常造成多种经济作物的减产甚至绝收.为了对栎黄枯叶蛾幼虫的寄主选择机制进行深入了解,该研究在室内条件下,选取刺槐、柠条、旱柳、山杨、山杏和沙棘六种植物,采用双向选择实验方法,研究了栎黄枯叶蛾幼虫对六种植物的取食偏好性.并利用傅里叶变换红外光谱(FTIR)和X射线衍射(XRD)对六种供选植物的化学成分和物理结构进行了光谱学研究.研究结果表明,当寄主沙棘与山杏、山杨、旱柳、柠条、刺槐存在时,幼虫比较倾向于选择沙棘.栎黄枯叶蛾幼虫对六种植物的取食偏好性的顺序依次为:沙棘>山杏>旱柳>山杨>刺槐>柠条.FTIR谱图显示,六种植物在光谱特征吸收峰的位置、数目及形状上基本相似,差异不明显.通过对三个FTIR吸光度比率的分析后发现:植物中的脂类和多糖含量是影响幼虫取食选择的关键因素.通过XRD检测,测得了六种供试植物的结晶度.通过对结晶度变化趋势和幼虫取食偏好性的对比发现:结晶度可能一定程度上影响植物的适口性,进而影响了幼虫对寄主植物的取食偏好.该研究是光谱学分析方法首次应用于昆虫寄主选择机制的研究,将为深入研究昆虫与植物在分子层面上的互相影响开辟蹊径.