Odorant-Binding Protein Interactions with Herbivore-Induced Volatiles Drive Behavioral Attraction of <i>Harmonia axyridis</i> (Coleoptera: Coccinellidae) to Tuta Absoluta-Infested Tomato Plant

<i>Tuta absoluta</i> severely constrains global tomato production. We investigated the behavioral attraction of <i>Harmonia axyridis</i> to infested plants and the molecular basis of herbivore-induced plant volatile (HIPV) recognition. Y-tube bioassays showed statistically significant attraction of <i>H. axyridis</i> to the infested plant (χ² = 13.72, <i>P</i> < 0.05). Molecular docking showed strong HaxyOBP-HIPV interactions, with predicted binding energies reaching -7.6 kl mol^-1 and ligand efficiencies of more than 0.30 kl mol^-1 per heavy atom. HaxyOBP13, HaxyOBP19, and HaxyOBP23 were found to have the most stable complexes with 1,3-cyclohexadiene-1-carboxaldehyde, 2,6,6-trimethyl, 1-methyl-3-(1-methylethyl), and beta-phellandrene during 100 ns molecular dynamics simulations, maintaining RMSD values within 0.15-0.30 nm. The competitive binding assays confirmed micromolar affinities, with dissociation constants (<i>K</i>_d) ranging between 6.45 and 14.58 μM. These behavioral, computational, and biochemical findings define important OBPs that mediate the perception of HIPV in <i>H. axyridis</i>, which forms the basis of volatile-mediated improvement of biological control measures against <i>T. absoluta</i>.