Divergence of the diapause transcriptome in apple maggot flies: winter regulation and post-winter transcriptional repression

Duration of dormancy regulates seasonal timing in many organisms and may be modulated by day length and temperature. Though photoperiodic modulation has been well studied, temperature modulation of dormancy has received less attention. Here, we leverage genetic variation in diapause in the apple maggot fly, Rhagoletis pomonella, to test whether gene expression during winter or following spring warming regulates diapause duration. We used RNAseq to compare transcript abundance during and after simulated winter between an apple-infesting population and a hawthorn-infesting population where the apple population ends pupal diapause earlier than the hawthorn-infesting population. Marked differences in transcription between the two populations during winter suggests that the ‘early’ apple population is developmentally advanced compared to the ‘late’ hawthorn population prior to spring warming, with transcripts participating in growth and developmental processes relatively up-regulated in appl...