Vol. 9, Issue 9, Part E (2025)

Insect-plant interactions form the backbone of terrestrial ecosystems, influencing biodiversity, ecosystem stability, and agricultural productivity. These interactions are governed by complex biochemical processes that regulate defence, communication, and adaptation. Climate change stressors, including elevated CO₂, heat waves, drought, and air pollution, profoundly reshape these biochemical dynamics by altering primary metabolism, secondary metabolites, and hormonal signalling. Such shifts influence insect feeding, detoxification strategies, and the stability of multitrophic networks, ultimately affecting crop protection and pollination services. Insects exhibit remarkable biochemical plasticity, including enzyme adaptation, detoxification, sequestration, and antioxidant defences, allowing them to persist in stressed environments. This review synthesises current understanding of biochemical responses in plants under climate stress, the adaptive mechanisms of insects, and disruptions in tri-trophic signalling. Case studies highlight how stress-modulated metabolites reshape pest dynamics in crops like cotton and ecological relationships in specialist systems such as monarch-milkweed. Understanding these biochemical shifts is vital for designing climate-resilient integrated pest management (IPM) strategies, breeding stress-tolerant cultivars, and applying defence-priming technologies. A systems-level, biochemically informed approach is essential to sustain agriculture under accelerating climate change.