Space-Dependent Oviposition Preference in Drosophila

Oviparous animals optimize egg-laying site selection through multimodal integration of environmental cues. Previous studies have established Drosophila as an ideal model to study egg-laying decision-making based on evaluating food ingredients and hardness, but how spatial cues direct oviposition strategies remains poorly understood. Here, we established behavioral assays for studying space-dependent oviposition preference in Drosophila, and identified Pickpocket 26 (Ppk26), a member of the DEG/ENaC family, regulating oviposition preference on waved versus flat surfaces. ppk26-expressing sensory neurons respond to ovipositor contact and specifically mediate flatness-based oviposition preference, but not other spatial or non-spatial preferences. Moreover, we found that a waved surface allowed more contact with flies' ovipositor to preferentially activate ppk26-expressing neurons and facilitate egg insertion into the waved oviposition site. These findings highlight a role for spatial cues in oviposition decision-making and establish ppk26 as a key mediator of contact-based spatial encoding during oviposition site selection.