Olfaction is essential for the survival of insects,and pheromone perception is thought to be mediated by pheromone binding proteins(PBPs)in lymph surrounding the olfactory receptors.To understand the physiological function of the PBPs,we cloned three full-length PBPs from the antennae of the yellow peach moth,Conogethes punctiferalis(Lepidoptera: Crambidae)and expressed in vitro.Protein-ligand binding assays of three PBPs to 30 odorants including 27 host plant volatiles and 3 sex pheromones revealed the specific binding to female sex pheromones of C.punctiferalis.PBP1 showed high binding affinity to the main sex pheromone components,(Z)-10-hexadecenal(Z10-16: Ald).PBP2 displayed high binding affinities with(E)-10-hexadecenal(E10-16: Ald).Furthermore,they also showed good binding ability with the maize volatiles 1-tetradecanol and β-farnesene.However,PBP3 did not respond to any chemicals tested in this study.Three-dimensional modeling of PBP1 and PBP2 to well binding sex pheromones Z10-16: Ald and E10-16: Ald showed Ser9 and Arg120 in PBP1 and Lys113 and Phe9 in PBP2 as the key amino acids in pheromone binding.Our studies suggested that PBP might play the essential role in the process of pheromone recognition and the well binding volatiles may help females to locate suitable oviposition sites.