Symbiont-mediated insecticide resistance in insect hosts: Mechanisms and integrated management prospects

The rapid escalation of insecticide resistance poses a profound threat to global food security and public health. While chemical resistance mechanisms are well characterized, the functional contribution of symbiotic microorganisms has only recently gained prominence. However, the intricate molecular cross-talk between insect symbionts and host detoxification pathways remains poorly defined, constraining our capacity to leverage these interactions for resistance management. This review synthesizes current findings on how endosymbionts and gut microbiota modulate insecticide resistance across diverse pest lineages. We critically evaluate evidence from multiple systems, underscoring the inherent complexity and context-dependency of symbiont-mediated effects. A pivotal insight emerging from this synthesis is the dual role of specific symbionts, which may either augment or attenuate host resistance contingent upon environmental stressors and host genetic architecture. Building on these foundations, we propose a "holobiont" that conceptualizes the insect host and its associated microbiota as a unified functional entity in the evolution of resistance. This framework identifies discrete molecular interfaces and symbiont taxa as promising candidates for intervention. By integrating mechanistic insights with applied objectives, this review delineates a strategic roadmap for the development of sustainable, next-generation tools to mitigate the spread of insecticide resistance.