GLOBAL MODELS OF HERBIVORY VARIABILITY: DATA FROM THE HERBVAR PROJECT

Herbivory is a major selection pressure on plants, which have evolved many different physical and chemical adaptations to prevent animals from eating their tissues. Mean herbivory patterns have been well studied in ecology. However, herbivory pressure can be highly variable, among different species of plants, and even between plants in the same population. The Herbivory Variability Network consortium used standardized surveys to compare herbivory variability within populations at 790 sites across five continents, on various families of plants. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Such patterns of variability in herbivory-related selection pressures could explain variations in plants' induced or constitutive defense capacities across latitudes, families or individual sizes. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. These findings highlight how variation in species interactions can influence eco-evolutionary outcomes We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.