Ricklefs Robert E
Department of Biology, University of Missouri-St Louis, St Louis, MO 63121-4499, USA.
Oecologia. 2008 Aug;157(1):53-67. doi: 10.1007/s00442-008-1050-x. Epub 2008 May 17.
This study addresses the influence of foliage chemistry on the distribution of Lepidoptera larvae across species of trees. I used ordination and analysis of principal coordinates to describe the partitioning of the larvae of 24 species of Lepidoptera over 23 species of host trees taking into account 13 chemical properties of the foliage. Canonical analysis of principal coordinates (CAP) revealed two significant axes linking the two datasets. The first constrained axis (r(2)=0.83) was associated with increasing amounts of soluble carbohydrates and decreasing amounts of hemicellulose, polyphenols, and potassium per cm(2) leaf area. The second constrained axis (r(2)=0.68) was associated with increasing amounts of soluble carbohydrates and decreasing magnesium. Variation in nitrogen and phosphorus, which are major factors in larval nutrition, were not associated with turnover of Lepidoptera species between species of host tree. Of the total variance in the positions of tree species on the first four constrained CAP axes, 44% was correlated with positions determined by foliage chemistry, 32% on the first two constrained axes. Within the space described by the first two canonical axes, congeneric species of tree clustered together, with the exception that Acer negundo was removed from other species of Acer, which grouped in a tight cluster with species in the order Fagales, as well as with Tilia and Ulmus. Alnus and Prunus also grouped together. No species of tree with a negative score on constrained axis 2 exhibited high Lepidoptera species richness, but the average number of individuals per collection tended to be high. These tree species also contain triterpenes in their leaves and harbored disproportionately more tent- and web-making species of Lepidoptera. These analyses show that patterns of distribution across host tree species within an assemblage of Lepidoptera species can be understood, at least in part, in terms of the qualities of the resources upon which they feed.
本研究探讨了叶片化学性质对鳞翅目幼虫在不同树种间分布的影响。我运用排序和主坐标分析，在考虑叶片13种化学性质的情况下，描述了24种鳞翅目幼虫在23种寄主树上的分布情况。主坐标典型分析（CAP）揭示了连接这两个数据集的两个显著轴。第一个约束轴（r(2)=0.83）与每平方厘米叶面积中可溶性碳水化合物含量增加以及半纤维素、多酚和钾含量减少相关。第二个约束轴（r(2)=0.68）与可溶性碳水化合物含量增加和镁含量减少相关。氮和磷是幼虫营养的主要因素，其变化与寄主树种间鳞翅目物种的更替无关。在树种种群在前四个约束CAP轴上位置的总方差中，44%与由叶片化学性质决定的位置相关，在前两个约束轴上为32%。在前两个典型轴所描述的空间内，同属树种聚集在一起，但梣叶槭与其他槭属树种分开，其他槭属树种与壳斗目树种以及椴树和榆树紧密聚集在一起。桤木和李属也聚集在一起。在约束轴2上得分呈负向的树种，没有表现出高的鳞翅目物种丰富度，但每次采集的个体平均数往往较高。这些树种的叶子中还含有三萜类化合物，并且栖息着不成比例的更多造帐篷和织网的鳞翅目物种。这些分析表明，在一组鳞翅目物种中，寄主树种间的分布模式至少部分可以根据它们所取食资源的质量来理解。
