Data from: The relative importance of plant intraspecific diversity in structuring arthropod communities: a meta-analysis

1. Understanding how plant diversity influences higher trophic levels is important for predicting the consequences of global biodiversity loss. While early studies have focused on the effects of plant species richness, more recently a growing number of experiments have explored the effects of plant intraspecific diversity by manipulating the genotypic richness of plant communities. 2. By combining 162 estimates of effect size from 60 experimental studies, we examined the effects of plant genotypic richness on arthropods, one of the most diverse and abundant taxa which play a crucial role in many ecosystem processes and services. We have also compared the effects of plant genetic and species diversity on arthropods when both were manipulated within the same study. 3. Species richness and abundance of most trophic groups of arthropods was higher in genetically diverse plant stands. Interestingly, the effects of plant genetic diversity on natural enemies of herbivores were stronger than the effects of plant genetic diversity on herbivores, suggesting that plant genetic diversity effects on predators might be driven by mechanisms independent of herbivores. 4. Herbivore and predator abundance increased with plant genetic diversity in studies using wild plants whereas predator abundance was unaffected and herbivore abundance was reduced by crop genetic diversity. Damage by generalist herbivores was reduced by plant genetic diversity whereas damage by specialist herbivores was not affected. 5. When the effects of plant genetic and species diversity on arthropods were compared within the same study, the magnitude of plant genetic diversity effects was comparable to that of plant species diversity. 6. Our results suggest that plant genetic diversity has significant effects on the diversity of arthropods across several trophic levels, thus highlighting the importance of maintaining high levels of both plant species and genetic diversity for arthropod conservation. However, the potential of using crop genetic mixtures in agriculture for pest control appears to be limited as even though herbivore abundance was reduced in genetically diverse plots, herbivore damage and predator abundance were not affected by crop genotypic richness.1. 探明植物多样性对高营养级（higher trophic levels）的影响机制，对预测全球生物多样性丧失的后续效应至关重要。早期研究多聚焦于植物物种丰富度（plant species richness）的生态效应，而近年来越来越多的实验通过调控植物群落的基因型丰富度（genotypic richness），探究植物种内多样性（intraspecific diversity）的影响。2. 本研究整合了60项实验研究中的162个效应量（effect size）估计值，探究了植物基因型丰富度对节肢动物（arthropods）的影响——节肢动物是物种多样性与个体丰度均位居前列的类群（taxa），在诸多生态系统过程与服务中发挥关键作用。此外，本研究还在同一实验中同时调控植物遗传多样性与物种多样性的前提下，对比了二者对节肢动物的影响。3. 在基因型多样的植物样地中，多数节肢动物营养类群（trophic groups）的物种丰富度与个体丰度均显著更高。值得注意的是，植物遗传多样性对植食性动物天敌（natural enemies of herbivores）的效应强于其对植食性动物本身的效应，这表明植物遗传多样性对捕食者（predators）的影响可能由不依赖植食性动物的调控机制所驱动。4. 在以野生植物为实验材料的研究中，植食者与捕食者的丰度随植物遗传多样性升高而增加；而在作物相关研究中，捕食者丰度未受作物遗传多样性影响，但植食者丰度有所降低。植物遗传多样性可降低广食性植食者（generalist herbivores）造成的危害，但对专食性植食者（specialist herbivores）引发的危害无显著影响。5. 在同一研究中直接对比植物遗传多样性与物种多样性对节肢动物的效应时，植物遗传多样性的效应强度与植物物种多样性相当。6. 本研究结果表明，植物遗传多样性对多个营养级的节肢动物多样性均具有显著影响，这凸显了维持高水平植物物种多样性与遗传多样性，对节肢动物保护（arthropod conservation）的重要性。不过，农业生产中利用作物基因混合种植（crop genetic mixtures）进行害虫防治（pest control）的潜力似乎有限：尽管基因型多样的作物样地中植食者丰度有所降低，但作物基因型丰富度并未对植食者危害程度与捕食者丰度产生显著影响。