The gut microbiome of Haemaphysalis longicornis mediates detoxification of the plant-derived insecticide Cinnamaldehyde

Botanical insecticides offer a sustainable alternative to synthetic pesticides, but their inconsistent efficacy limits widespread use. Here, we show that the gut microbiome of Haemaphysalis longicornis may function as a symbiotic detoxification shield. Through integrated multi-omics and culture-based approaches, this study demonstrates that cinnamaldehyde exposure triggers a rapid restructuring of the gut microbiota, selectively enriching specific bacterial taxa, notably Pseudomonas . This community shift establishes a potent microbial detoxification circuit. Metagenomic reconstruction and metabolomic profiling reveal that these bacteria co-opt enzymatic pathways, including those for environmental pollutant degradation, to break down cinnamaldehyde, as confirmed by in vitro degradation assays. This microbial detoxification shield significantly reduces the compound’s toxicity to the tick host. Our findings reveal that a resilient and adaptive gut microbiome constitutes a major bottleneck limiting the performance of botanical insecticides. This insight shifts the development of next‑generation green pesticides from chemical optimization alone toward strategies that target the pest microbiome, opening a promising avenue for sustainable pest control.