Introduction: Ecology and Evolution of Plant-Herbivore Interactions on Islands

Islands provide singular yet powerful natural settings for testing ecological and evolutionary hypotheses and have been particularly informative for disentangling the drivers and consequences of species interactions. Damage to plants inflicted by vertebrate and invertebrate herbivores represents an especially strong and ubiquitous force on island life which early on caught the attention of biologists. There are numerous biotic and abiotic factors that potentially explain herbivory patterns on islands, and yet many of these remain elusive or have simply not been tested. This book seeks to integrate current research on plant-herbivore interactions on islands, including both syntheses and empirical studies, shedding new insight and pointing to candidate mechanisms that explain variability in herbivory patterns on islands. Specifically, this book addresses research testing for patterns of variation in herbivory in relation to different types of plant traits associated with vertebrate and invertebrate herbivory on islands, as well as toisland features or processes classically studied in population ecology or island biogeography but less tested on plant-herbivore interactions. These include island area or distance to mainland, temporal (e.g., successional) and spatial (e.g., metapopulation) dynamics, and herbivore invasions or extinctions. Novel insight is gained by establishing links between or jointly testing these drivers, as well as by harnessing ecological complexity such as through the study of food web dynamics to explain herbivory and plant trait variation on islands. Likewise, several chapters deliver new syntheses that uncover novel patterns and can help pave the way for future empirical studies. Overall, these studies contribute to understanding how biotic and abiotic factors acting at different temporal and spatial scales shape plant-herbivore interactions on islands, and in turn how such effects influence island biological systems.