Data from: Herbivore effect traits and their impact on plant community biomass: an experimental test using grasshoppers

1. Using trait-based approaches to study trophic interactions may represent one of the most promising approaches to evaluate the impact of trophic interactions on ecosystem functioning. To achieve this goal, it is necessary to clearly identify which traits determine the impact of one trophic level on another. 2. Using functionally contrasting grasshopper species, we tested the ability of multiple traits (morphological, chemical and biomechanical) to predict herbivore impact on the biomass of a diverse plant community. We set up a cage experiment in an old species rich grassland field and evaluated how multiple candidate grasshopper effect traits mediated herbivore impact on plant biomass. 3. Grasshoppers had different impact on plant community biomass (consuming up to 60 % of plant community biomass). Grasshopper impact was positively correlated with their incisive strength while body size or grasshopper C:N ratio exhibited low predictive ability. Importantly, the strong relationship between the incisive strength and the impact was mediated by the grasshopper feeding niche, which was well predicted in our study by two simple plant traits (leaf dry matter content, leaf C:N ratio). Feeding niche differences between grasshoppers were explained by differences in incisive strength, highlighting the fundamental linkage between grasshopper effect traits and their niche. 4. Our study contributes to the development of the trait-based approach in the study of trophic interactions by providing a first experimental test of the relationship between herbivore effect traits, their impact on plant community biomass, and in a larger extent on ecosystem functioning. By comparing the relative importance of multiple interacting grasshopper traits, our study showed that incisive strength was a key effect trait which determined grasshopper feeding niche and its relative impact on plant community biomass.

1. 基于性状的研究方法（trait-based approaches）用于探究营养级互作（trophic interactions），是评估营养级互作对生态系统功能（ecosystem functioning）影响的极具前景的研究途径之一。若要达成此目标，需明确甄别哪些性状决定了某一营养级（trophic level）对另一营养级的影响。2. 本研究选取功能特征存在显著分化的蝗虫物种，测试了多类性状（形态、化学及生物力学性状）对植食性动物（herbivore）影响多样植物群落（plant community）生物量（biomass）的预测能力。我们在物种丰富的成熟草原地块开展笼养实验（cage experiment），并评估了多种候选蝗虫效应性状（effect traits）如何介导植食性动物对植物生物量的影响。3. 蝗虫对植物群落生物量的影响存在显著差异，最高可消耗60%的植物群落生物量。蝗虫的影响与其切咬强度（incisive strength）呈正相关，而体型大小或蝗虫碳氮比（C:N ratio）的预测能力则较低。值得注意的是，切咬强度与影响程度之间的强相关性由蝗虫取食生态位（feeding niche）介导，而本研究中取食生态位可通过两类简单的植物性状（叶片干物质含量（leaf dry matter content）、叶片碳氮比（leaf C:N ratio））实现良好预测。蝗虫间的取食生态位差异可由切咬强度的差异加以解释，这凸显了蝗虫效应性状与其生态位之间的本质关联。4. 本研究首次通过实验验证了植食性动物效应性状、其对植物群落生物量的影响，以及更大尺度上对生态系统功能的影响三者间的关联，为营养级互作研究中的基于性状研究方法发展提供了助力。通过对比多类相互作用的蝗虫性状的相对重要性，本研究证实切咬强度是决定蝗虫取食生态位及其对植物群落生物量相对影响的关键效应性状。