Enhanced Female Preference to Oviposition Cues by Mating Induced Odorant-Binding Proteins in Bactrocera dorsalis (Hendel)

Mating is a key physiological state that changes insect olfactory sensitivity. Generally, mating-dependent olfactory plasticity reduces female responses to sex pheromones while elevating responses to oviposition cues. Beyond modulating behavioral preferences, mating induces transcriptional reprogramming of chemosensory genes such as odorant-binding proteins (OBPs). Therefore, mating-dependent OBPs represent strong candidate proteins mediating the enhanced perception of oviposition cues in mated females. We found that mating resulted in the upregulation of several OBPs in an invasive pest, Bactrocera dorsalis (Hendel). Among them, OBP84a-2 bound to two oviposition cues (1-octen-3-ol and γ-octolactone) of B. dorsalis and OBP28a-2 bound to 1-octen-3-ol through binding-affinity assays, molecular docking, gene editing, and behavioral assays. Our results revealed that OBP84a-2 and OBP28a-2 played a role in perceiving oviposition cues. The results will facilitate the understanding of the molecular basis of the olfactory behaviors in B. dorsalis, which may provide potential targets for novel female attractant development against this notorious fly.