Within-crown variability in herbivore performance and leaf traits

Functional trait variation within individual plants is predicted to have important ecological consequences. However, our understanding of the sources contributing to subindividual trait heterogeneity, and the ramifications thereof, is poor. In a common garden, we sampled multiple genotypes of mature trembling aspen (Populus tremuloides) at different vertical crown levels and quantified the contributions of genetic, spatial and biotic (herbivory) factors to subindividual morphological and chemical leaf trait variance. Bioassays using gypsy moth (Lymantria dispar L.) caterpillars were conducted to study impacts of spatial and genotypic factors on insect performance. Crown position was the primary source of subindividual variation in leaf morphology and explained more of the variance in morphological traits than tree genotype. Effects of spatial, genetic and biotic factors on within-crown chemistry were highly compound-specific. For many compounds, changes in within-crown concentrat...单株植物内的功能性状变异被认为具有重要的生态学效应。然而，目前学界对导致亚个体性状异质性的成因及其潜在影响的认知仍较为匮乏。 在同质园试验中，我们对不同冠层垂直梯度的成熟颤杨（Populus tremuloides）多个基因型进行采样，并量化了遗传、空间及生物（植食性）因素对亚个体叶片形态与化学性状变异的贡献。本研究采用舞毒蛾（Lymantria dispar L.）幼虫开展生物测定，以探究空间与基因型因素对昆虫生长表现的影响。 冠层位置是叶片形态亚个体变异的主要来源，其对形态性状变异的解释度高于树木基因型。空间、遗传与生物因素对冠层内化学性状的影响具有极强的化合物特异性。对于多数化合物而言，冠层内浓度的变化……