Expression of short neuropeptide F and prothoracicotropic hormone in relation to photoperiodic regulation of pupariation and pupal diapause in the flesh fly, Sarcophaga similis (Diptera: Sarcophagidae)

Abstract

The photoperiodic regulation of pupariation and pupal diapause was investigated in the flesh fly, Sarcophaga similis (Diptera: Sarcophagidae), focusing on the roles of short neuropeptide F (sNPF) and prothoracicotropic hormone (PTTH). Under long-day conditions, pupariation occurred earlier than under short-day conditions, corresponding to an earlier peak in hemolymph ecdysteroid titer. The molecular elements regulating the transient ecdysteroid surge for pupariation remain unknown. After pupation, the ecdysteroid titer remained higher in long-day individuals, preventing diapause. Notably, sNPF and Ptth were simultaneously upregulated before the increase in ecdysteroids under long days, followed by upregulation of an ecdysteroidogenesis gene neverland (nvd). These results suggest that the downregulation of sNPF and Ptth under short days is involved in the downregulation of nvd and ecdysteroids, initiating diapause. This study provides insights into the photoperiodic regulation of diapause, highlighting the potential involvement of sNPF and PTTH, but further research using data-driven multi-omics approaches is necessary to elucidate the molecular mechanisms underlying these photoperiodic responses.