Multiple mechanosensory pathways mediate oviposition behavior in Bactrocera dorsalis (Diptera: Tephritidae)

Substrate stiffness and internal pressure play key roles in mediating insect adaptability to mechanical cues through various mechanosensitive pathways. However, the involvement of mechanosensory perception in oviposition behavior of tephritid flies remains largely unexplored. Given that frugivorous tephritid flies use extraordinarily sharp-tipped ovipositors to probe the stiff fruit peel before laying eggs, we speculated that mechanosensory-responsive pathways mediate the oviposition behavior.

In this study, we combined oviposition assays and RNA interference (RNAi) techniques to investigate how mechanosensory pathways mediate oviposition behaviors in the notorious invasive tephritid fly, Bactrocera dorsalis. The results show that both substrate stiffness and ovarian distention influenced the oviposition decision of female flies. Furthermore, silencing the BdTMC gene impaired the ability of flies to discriminate substrate hardness, while treatment with dsBdNomPC disrupted the internal pressure balance, leading to the accumulation of eggs in the ovary. Notably, a neuropeptide, BdNPLP1 was found to be involved in mechanosensitive signal transduction downstream of BdTMC and BdNomPC.

Overall, our findings decipher the molecular mechanism underlying mechanosensory pathways mediating egg-laying behavior in B. dorsalis. We propose that oviposition decision-making is driven by a combination of internal and external mechanosensitive inputs, which offer new insights into the complex system of insect egg-laying regulation. © 2025 Society of Chemical Industry.