Effects of genetic varitation in host plants on herbivourous insect communities

为了研究寄主植物遗传变异对食草昆虫群落的影响，我们重点研究了日本栎与鳞翅目采叶蚁的关系。我们得到了以下结果。基于3个基因核苷酸序列的系统发育分析，区分了日本栎属、白栎属、白栎属和cyalobalanopsis属的3个谱系。本文报道了一种仅以Q为食性的叶状纲新种。包括本新种在内的四种日本菌复合体对亲缘关系较近的寄主橡树有特定的偏好。基于叶片性状的判别分析，在北海道石kari栎林116个样本中，检测到齿齿栎（Q. dentata）和脆皮栎（Q. crispula） 11株形态中间树。在中间树中，有6棵是齿齿栎特有树种和齿齿栎特有树种。叶冠菌每叶面积的密度与叶片大小、叶片湿重、叶片韧性呈显著负相关，而花冠菌和柱头菌的密度与叶冠菌的密度呈显著正相关。叶绿虫幼虫的存活率与任何叶片性状无关。结果表明，人工破坏叶片单位面积氮浓度高于对照叶片。然而，在齿齿苋中，它们之间没有差异。两种栎树在人工破坏叶与对照叶间的千层线虫密度无显著差异。6种落叶栎树上寄生蜂类群在物种组成上的相似性不能很好地由寄主叶螨、寄主食物栎或地理位置等单一因素来解释采食亮叶的家蚕幼虫的生长性能显著高于采食阴叶的家蚕幼虫。这些结果表明，除了种间和种内变异外，叶片性状的树内变异在草食性昆虫群落的组织中也很重要。少

In order to examine effects of genetic variation in host plants on herbivourous insect communities, we focused on relations between Japanese oaks and lepidopteran leafminers. We obtained the following results.1. Phylogenetic analysis baaed on nucleotide sequences of three genes distinguished three lineages in Japanese taxa of Quercus, Cerris-Ilex, white-oak (sensru strict) and Cyalobalanopsis.2. One new Phyllonorycter species feeding on only Q, dentata was described. The four species of nipponicella complex including this new species have specific preferences for host oaks with close relatons.3. Discriminant analysis based on several leaf traits detected 11 morphologically intermediate trees of Q. dentata and Q, crispula among 116 individuals examined in oak forest of Ishikari, Hokkaido. Of the intermediate trees, six were mined by both Q. dentata-specific and Q. crispula-specific Phyllonorycter species.4. Mine density of Phyllonorycter per leaf area often negatively correlated with le … More af size, leaf wet weight per area or leaf toughness, but densities of Caloptilia and Stigmella frequently positively correlated with them. The survival of Phyllonorycter larvae was not related to any leaf traits.5. In Q. crispula, nitrogen concentration per unit area was higher in artificially damaged leaves than in control leaves. In Q. dentata, however, it did not differ between them. Both oaks showed no difference in the density of Phyllonorycter mines between artificially damaged and control leaves.6. The similarity of parasitoid assemblages on six deciduous oaks in terms of species composition was not well accounted for by one factor such as host leafminer, host food-oak or geographic location..7 Silkmoth larvae fed by sunny leaves of Q. acutissima showed a significantly higher growth performance than those fed by shade leaves.These results suggest that not only inter- and intra-species variation but also intra-tree variation of leaf traits are important in organizing herbivorous insect communities. Less