纬向不同地理种群栓皮栎虫食特征及其与气象因子的关系

Entomic Herbivory Characteristics of Quercus variabilis Leaves and Correlation with Meteorological Factors across Different Geographical Regions

昆虫对叶片的取食是植物群落的普遍特征,为了探讨纬度和气象因子对虫食作用的影响,本文调查了我国纬向6个地理区域（北纬26°～40°,约跨14°）栓皮栎叶片虫食特征及分布格局,结果表明：（1）不论成年树还是幼树栓皮栎,叶片虫食率和虫食频度随纬度的减小呈显著增加的趋势（P≤0.05）;（2）比较各地理区域虫食结构特征发现,随纬度的减小,成年树和幼树栓皮栎其未受虫食叶片的比例逐渐减少,甚至趋于0,而受中、强度虫食（〉25%）的叶片的比例逐渐增加;即低纬度地区具有更强的虫食作用;（3）除了低纬度样点（湖南城步）外,其余各区域栓皮栎叶片其虫食程度主要集中在0.5%～5%;（4）双因素方差分析表明栓皮栎在不同个体发育阶段受虫食作用存在显著差异,总体表现出幼树叶片虫食率显著高于成年树（P〈0.05）;（5）不同地理区域栓皮栎成年树及幼树叶片的虫食率、虫食频度与年降雨量呈显著正相关（P〈0.05）,而与年均温无显著相关关系;同时,成年树和幼树叶片的虫食频度与极端最低温呈显著正相关（P〈0.05）。

Herbivory is the common characteristics of plant community. To explore the effects of latitude and meteorological factors on herbivory,we investigated the entomic herbivory characteristics of Quercus variabilis leaves acorss different geographical regions,with a 14° latitudinal spanning from 26° N（ Chengbu,Hu ＇nan Province） to 40° N（ Beijing）. Either the mature tree or juvenile tree,leaf herbivory rate and frequency significantly increased toward the equator or at lower latitudes（ P〈 0. 05）. According to the insect herbivory structure,the proportion of the non-chewed leaves decreased,while the proportion of the above 25%-chewed leaves increased toward the equator. Namely,it shows strong herbivory at lower latitudes. Except the southest site（ Chengbu,Hu＇nan Province）,the proportion of herbivory mainly concentrated between 0. 5%- 5% for all other sites. Leaf herbivory rates in the juvenile tree were significantly higher than that in the mature tree（ P〈 0. 05）. Multiple regression results revealed significant effects of annual precipitation and minimum temperature of the coldest month on leaf herbivory rate and frequency despite ontogenic stages,but the maximum temperature of the warmest month significantly affected leaf herbivory frequency in the juvenile tree. Therefore, the latitudinal variation in leaf herbivory likely appears to be driven predominantly by variation in extreme temperature and precipitation.