Latitudinal variation in herbivory: hemispheric asymmetries and the role of climatic drivers

In the past, it was widely accepted that herbivory decreased with latitude. However, several empirical studies have failed to support this hypothesis, leading to strong debate. In addition to providing a quantitative assessment of the latitudinal gradient in herbivory, our study aims to provide new information about the role of climatic factors in shaping the latitudinal gradient in herbivory. Through the collection and analysis of published data on herbivory, we tested the latitudinal herbivory hypothesis (LH hypothesis) and the relationship of temperature and precipitation to herbivory. Based on 1890 data points distributed world-wide from more than 1000 plant species, our results show that herbivory decreased with latitude and increased with temperature only in the Northern Hemisphere. In contrast, in the Southern Hemisphere, herbivory did not have a relationship with latitude and tended to decrease with temperature.Synthesis. This study shows the LH hypothesis is supported only in the Northern Hemisphere and highlights the importance of temperature in explaining the pattern of herbivory at the global scale. These possible hemispheric asymmetries in herbivory should not be overlooked in future studies.