Climate change-driven eco-evolutionary process on herbivorous insect outbreak

Anthropogenic climate change has a major impact on herbivorous insect outbreaks. Altered temperature regimes can directly affect insect population demography by altering insect traits through both ecological and evolutionary mechanisms, as well as indirectly affecting population dynamics through biotic interactions. However, the eco-evolutionary processes in insect population-level dynamics that regulate outbreaks are not well understood, and how climate change alters these processes has remained poorly explored. In this review, we summarize how climate change affects the outbreaks of herbivorous insects through ecological and evolutionary effects on insect traits and trophic interactions among herbivorous insects, their host plants, and their natural enemies. We propose that climate-driven changes in insect traits increase outbreak frequency and magnitude, thereby generating eco-evolutionary feedback. Specifically, outbreaks themselves may shift the mode of outbreaks rather than simply increasing their frequency. Recognizing this process is essential for forecasting future outbreaks and developing management strategies that consider changes in the evolutionary potential of outbreak populations.