Functional Redundancy of Odorant Receptors in α-Humulene Mediates Ovipositional Behavior of a Cosmopolitan Insect Pest

Insects depend on sophisticated olfaction for survival. The diamondback moth (<i>Plutella xylostella</i>), a devastating pest with rapid reproduction and insecticide resistance, requires novel control strategies. However, its odor recognition mechanisms, particularly for host-emitted α-Humulene, remain unclear. We investigated two odorant receptor genes, <i>PxOR28</i> and <i>PxOR31</i>, which are highly expressed in female antennae. Cloning, qPCR, and CRISPR/Cas9 knockout demonstrated their essential role in mediating behavioral attraction to α-Humulene for oviposition. While α-Humulene activated wild-type antennae and attracted moths, mutants lacking both receptors exhibited no response, indicating functional redundancy. These findings elucidate <i>P. xylostella's</i> perception of α-Humulene and highlight chemosensory receptors or key odorants as targets for sustainable pest control.