Insect herbivory reshapes rhizosphere bacterial and fungal networks in a stage-specific manner

Plants rely on soil-dwelling microbes around their roots to grow and defend themselves. Yet we know little about how insects reshape root‑zone communities as plants develop, or whether this differs from simple wounding. We studied Arabidopsis thaliana fed on by the generalist caterpillar Spodoptera frugiperda before, during, and after flowering and compared these plants to those with mechanical damage. We found that insect feeding, not just injury, acts as a distinct disturbance that reorganizes the root‑zone microbial community in stage‑specific ways. It altered which microbes were present and how they interacted, strengthening links between bacteria and fungi and shifting likely nutrient and defense functions. These results reveal strong connections between aboveground attack and belowground life, with practical implications for breeding and managing crops for resilience and productivity.