Predator‐associated microbiomes as hidden modulators of pesticide‐compatible biological control in agroecosystems

Abstract Beneficial arthropod predators are central components of integrated pest management, yet their performance in crop systems is often variable because predator efficacy depends on interactions among host traits, prey availability, intraspecific and interspecific interactions, pesticide exposure and environmental stressors. Predator‐associated microbiomes, including gut microbiota, tissue‐resident bacteria and facultative or obligate endosymbionts, represent an overlooked functional layer that may influence predator nutrition, stress physiology, reproduction, behaviour, dispersal and pesticide tolerance. This review synthesizes evidence from spiders, ladybird beetles, green lacewings, earwigs and predatory Heteroptera, with emphasis on traits that determine biological pest control under agroecosystem pressure. A central contribution is an evidence hierarchy that distinguishes descriptive, associative, experimental, mechanistic and field‐level evidence. The strongest predator‐specific associations currently come from spiders, where tissue‐resident microbial assemblages have been linked to the spider insecticide survival, predicted detoxification pathways and physiological resilience under chemical stress; however, causal microbial mechanisms remain insufficiently tested. In other predator groups, microbiome‐associated patterns suggest plausible microbial contributions to predator performance, but experimentally validated microbiome‐mediated effects remain limited and are often inferred from symbiont surveys, diet‐induced shifts in predator‐associated microbiomes, reproductive manipulation and functional prediction. We argue that pest management research should move from descriptive microbiome profiling toward causal tests linking microbial taxa and functions to predator performance, pesticide compatibility and field‐scale pest suppression. Incorporating microbiome information and experimentally validated microbial traits into ecotoxicology, mass rearing and conservation biological control could improve the reliability and resilience of predator‐based pest suppression in agricultural landscapes. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.