Plant Functional Traits Better Explain the Global Latitudinal Patterns of Leaf Insect Herbivory than Climatic Factors

Herbivory reflects the interaction between plants and insects in ecosystems, and its latitudinal patterns at the global scale have attracted widespread attention. While many studies support the latitudinal herbivory hypothesis, it remains contentious. This study, based on a global dataset of 1206 herbivory records, explored the global latitudinal patterns of insect herbivory on leaves and their influencing factors. We found that herbivory decreased with increasing latitude from the equator to the poles, supporting the latitudinal herbivory hypothesis. Latitude affected the variation in climate, soil nutrients, and plant functional traits, which ultimately affected herbivory. Plant functional traits were the key factors affecting the global latitudinal patterns of herbivory, with climatic factors playing an important regulatory role, while soil nutrients had a relatively minor impact, explaining 7.3%, 4.66%, and 0.98% of the latitudinal variation in herbivory, respectively. Specifically, plant height and mean annual temperature were the most important drivers of the global latitudinal patterns of herbivory, explaining 3.39% and 3.03%, respectively. Our study focused on two new perspectives-plant functional traits and soil nutrients. Although soil nutrients had a relatively minor influence on the latitudinal patterns of herbivory, we emphasized the significant impact of plant functional traits on the latitudinal patterns of herbivory. Our findings provide new insights into understanding and predicting the geographic patterns of herbivory and ecological interactions in the context of global climate change, offering important references and ecological significance.