Climate change alters plant-herbivore interactions

ABSTRACT Plant-herbivore interactions have evolved in response to co-evolutionary dynamics, along with selection driven by abiotic conditions. We examine how abiotic factors influence trait expression in both plants and herbivores to evaluate how climate change will alter this long-standing interaction. The paleontological record documents increased herbivory during periods of global warming in the deep past. In phylogenetically-corrected meta-analyses, we find that elevated temperatures, CO 2 concentration, drought stress and nutrient conditions directly and indirectly induce greater herbivore consumption, primarily in agricultural systems. Additionally, elevated CO 2 delays herbivore development, but increased temperatures accelerate development. For annual plants, higher temperatures, CO 2 , and drought stress increase foliar herbivory, and our meta-analysis suggests that greater temperatures and drought may heighten florivory in perennials. Human actions are causing concurrent shifts in CO 2 , temperature, precipitation regimes and nitrogen deposition, yet few studies evaluate interactions among these changing conditions. We call for additional multifactorial studies that simultaneously manipulate multiple climatic factors, which will enable us to generate more robust predictions of how climate change could disrupt plant-herbivore interactions. Finally, we consider how shifts in insect and plant phenology and distribution patterns could lead to ecological mismatches, and how these changes may drive future adaptation and coevolution between interacting species.