Sustained metabolic defense and male-specific volatile repellence shape tea plant- Helopeltis theivora interactions

Plant-herbivore interactions are shaped not only by plant defensive responses but also by herbivore perception of host-associated chemical cues. However, how tea plants coordinate chemical defenses and how Helopeltis theivora responds behaviorally to induced plant signals remain poorly understood. Here, we combined transcriptomic, metabolomic, behavioral, and electrophysiological approaches to dissect the molecular mechanisms underlying tea defense activation and herbivore behavioral adaptation. Following H. theivora infestation, JA signaling and its bioactive derivatives were rapidly induced. Meanwhile, phenylalanine accumulation and auxin metabolic remodeling increased progressively with infestation pressure. Integrated transcriptomic and metabolomic analyses revealed coordinated activation of the phenylpropanoid-flavonoid pathway as a central metabolic defense module. Pinobanksin-3-acetate accumulated substantially and was identified as a potential chemical component contributing to tea resistance. In parallel, feeding-induced (E)-β-ocimene emission increased significantly and elicited dose-dependent behavioral avoidance in adult male H. theivora, suggesting that this volatile may function as an olfactory cue for assessing host defensive status. Together, our findings reveal a complex ecological consequence of herbivore-induced defense: tea plants enhance metabolic resistance while simultaneously releasing volatile signals that may influence herbivore host-selection behavior. These insights provide potential chemical targets for developing sustainable pest management strategies through manipulation of plant defense pathways and insect behavioral responses.