Annual Research & Review in Biology

Insecticides remain the primary tool for suppressing arthropod pests that threaten global food production, yet sustained and intensive use across diverse production systems has contributed to the repeated evolution of resistance in taxonomically diverse pest species. Using a narrative review approach, this article integrates molecular, ecological, and climate-related evidence to examine insecticide resistance as an evolutionary process shaped jointly by chemical selection, pest biology, and changing environmental conditions. This review synthesises current understanding of the molecular basis of insecticide resistance, encompassing target-site insensitivity, enhanced metabolic detoxification, reduced cuticular penetration, and altered behaviour, with particular attention to the genes and mutations that underlie resistance to pyrethroids, organophosphates, carbamates, neonicotinoids, diamides, and microbial toxins derived from Bacillus thuringiensis. The review then considers how anthropogenic climate change is reshaping the ecological and evolutionary context in which resistance arises, through range expansion, altered voltinism, changes in overwintering survival, and shifts in selection intensity associated with modified pesticide use patterns. Case studies drawn from the fall armyworm, diamondback moth, cotton bollworm, tomato leafminer, aphids, whiteflies, and mosquito disease vectors illustrate how these mechanisms interact with agronomic and climatic pressures in the field. This integrative framing distinguishes the review from mechanism-centred accounts by linking specific resistance pathways to field-level management decisions under shifting climatic and agronomic contexts. The review closes with an appraisal of resistance management strategies, including mode-of-action rotation, biotechnological interventions such as RNA interference and gene editing, and the integration of resistance monitoring into adaptive pest management frameworks. Persistent gaps remain in the translation of molecular diagnostics into field-deployable resistance management, and in anticipating how a warming climate will alter the tempo and geography of resistance evolution. Addressing these gaps will require closer integration between molecular entomology, agroecology, and climate science.