Climate and leaf traits, not latitude, explain variation in plant‐herbivore interactions across a species’ range

1. Spatial variation in abiotic and biotic factors creates local contexts that influence the intensity of plant‐herbivore interactions. Some previous studies have accounted for the complexity of these interactions with latitudinal clines, while the absence of such clines in many other systems suggests other, often unknown, local community factors may instead explain the variation in herbivory across populations.

2. We investigated plant‐herbivore interactions across the entire range of a long‐lived tree (Quercus garryana), evaluating the relative importance of climate, latitude, population size, and insect feeding guilds in determining leaf phenotype and the extent and variation in insect herbivory. In this ecosystem, rain shadows create a nonlinear relationship between climate and latitude, allowing us to disentangle the effects of environmental factors. By performing similar analyses on trees grown in a common garden, we were able to assess the relative importance of environmental ...