Good stress in good 'bugs'? pesticide-mediated stress in natural enemies

Exposure to sublethal stressor concentrations, which do not result in mortality, can trigger hormetic responses that enhance growth, reproduction or survival in both primary pest species and their secondary competitors, potentially contributing to the development of insecticide resistance and pest outbreaks. Hormesis, a dose-dependent biphasic response characterized by low-dose stimulation and high-dose inhibition, has garnered increasing attention in entomology and acarology owing to its significant implications for pest management and ecosystem service provision. By contrast, hormesis in natural enemies, such as pathogens, parasitoids and predators, can enhance their biological control performance under specific conditions. Although these responses may offer short-term benefits, they also introduce trade-offs and potential long-term risks. The underlying mechanisms of hormesis include hormonal modulation, stress-induced activation of cellular repair pathways and enhanced detoxification processes. Despite its significance, our understanding of hormesis in ecologically important insects and mites remains limited, with critical knowledge gaps regarding species-specific responses, the influence of environmental factors such as temperature and nutrition, and the long-term ecological consequences of repeated low-dose exposures. Furthermore, the interaction of multiple stressors, such as pesticide mixtures and abiotic factors such as climate change, remains poorly understood in the context of hormetic responses. Future research should focus on elucidating the molecular mechanisms of hormesis, its ecological implications, and the development of predictive models to assess its effects across various ecosystems. Integrating hormesis into pest management strategies could optimize pesticide use while minimizing adverse effects on beneficial organisms. Addressing these gaps is crucial for enhancing ecological resilience, safeguarding populations of beneficial organisms, and promoting sustainable agricultural practices in the face of environmental and anthropogenic challenges. © 2025 Society of Chemical Industry.