Gene expression profiling of diapause termination in E and Z strains of the European corn borer moth, Ostrinia nubilalis

Evolutionary change in diapause timing will be key for insects to adapt to a globally warming climate. However, the molecular mechanisms behind shifts in diapause timing are still unclear. The European corn borer moth (Ostrinia nubilalis) shows evolved differences in the length of larval diapause termination, where Z-strain individuals have a long termination time and E-strain individuals have a short termination time. Here, we use whole transcriptome profiling of larval head tissues through a developmental time-course of diapause termination to, i) identify putative loci responsible for initiating divergence in diapause timing, and ii) identify downstream molecular pathways that may direct moths to an earlier or later end of diapause. As diapause is induced under short-day conditions (12:12 light:dark) and broken under long-day conditions (16:8 light:dark), we sample both strains under short-day conditions during diapause maintenance, and on days 1 and 7 after exposure to long-day conditions during diapause termination, to illuminate the critical mechanisms for observed shifts to seasonal timing.