越来越多的证据表明,食草昆虫会影响新热带植物物种的局部组成和丰富度,特别是在物种丰富的属中。物种丰富,系统发育多样性,和化学多样性都影响昆虫食草动物寻找和利用宿主的能力。多样性的这些组成部分对物种共存和植物-草食动物相互作用的相对影响尚不清楚。我们在当地建立了60个多达13种Piper(胡椒科)的当地社区,哥斯达黎加低地湿润森林位置的成熟森林。选择每个群落的物种组成,使物种丰富度,系统发育多样性,和基于GCMS的化学多样性在社区之间独立变化。我们预测,化学多样性将对不同时间的社区产生最强烈的影响,具有较小的分类学和系统发育多样性的影响。实验种植后13个月,我们评估了每次切割的存活率,测量的幸存者的总叶面积损失,叶面积损失到通才和专业草食性昆虫物种,当地物种灭绝。通才和专家食草动物随着物种丰富度和系统发育多样性的增加而减少,分别。令人惊讶的是,化学多样性对草食动物损害的三种措施中的任何一种都没有独立的影响。然而,具有较高化学和系统发育多样性的地块显示出植物死亡率降低和当地物种灭绝。总的来说,我们的结果表明,化学和系统发育相似性是热带植物群落组装和维持的重要因素。化学多样性影响植物死亡率的事实表明,叶草食动物,可能还有其他植物天敌,可以通过相似化学型的选择性死亡率增加植物多样性。
Accumulating evidence suggests that herbivorous insects influence the local composition and richness of Neotropical plant species, particularly in species-rich genera. Species richness, phylogenetic diversity, and chemical diversity all influence the ability of insect herbivores to find and utilize their hosts. The relative impact of these components of diversity on species coexistence and plant-herbivore interactions is not well understood. We constructed 60 local communities of up to 13 species of Piper (Piperaceae) in native, mature forest at a lowland wet forest location in Costa Rica. The species composition of each community was chosen such that species richness, phylogenetic diversity, and GCMS-based chemical diversity were varied independently among communities. We predicted that chemical diversity would most strongly affect the communities across time, with smaller effects of taxonomic and phylogenetic diversity. At 13 months after the experimental planting, we assessed survivorship of each cutting, measured total leaf area loss of the survivors, leaf area loss to generalist and specialist herbivorous insect species, and local extinction of species. Generalist and specialist herbivory decreased with increasing levels of species richness and phylogenetic diversity, respectively. Surprisingly, there was no independent effect of chemical diversity on any of the three measures of herbivore damage. Nevertheless, plots with a higher chemical and phylogenetic diversity showed decreased plant mortality and local species extinction. Overall, our results suggested that both chemical and phylogenetic similarity are important factors in the assembly and maintenance of tropical plant communities. The fact that chemical diversity influences plant mortality suggests that leaf herbivores, and possibly other plant natural enemies, could increase plant diversity via the selective mortality of similar chemotypes.