Understanding how complex ecological interactions are responding to global change is a major challenge. Plants and their associated insect herbivores make up most of macroscopic diversity, yet how these interactions have shifted with global change remains underexplored. To address this gap, we quantified herbivory on herbarium specimens from four plant species with records extending back over 112 years. Our study focused in the northeastern US, where temperatures have increased rapidly with climate change.
Results/Conclusions
Herbarium specimens collected within the past 10 years were 23% more likely to be damaged by herbivores than plants collected in the early 1900s. Herbivory also increased significantly with winter temperature and decreasing latitude, suggesting that climate warming may drive increasing herbivory over time. To explore whether changes in the insect herbivore community might explain shifts in herbivory, we used observational records to build climate occupancy models for insect herbivores of our focal plant species. These models implicate winter temperature as a key driver of insect herbivore presence, supporting a link between insect herbivores and increased herbivory. In contrast, human population densities were negatively associated with herbivory and occupancy for the majority of herbivores, indicating that urbanization may disrupt the effects of climate change on insect herbivory.