Transcription Analysis of Overwintering Dormancy in the Blue Orchard Bee

The solitary bee Osmia lignaria is an emerging pollinator of growing economic importance. They are unique in that they become dormant two times at different developmental stages in response to very different environmental conditions. Larva develop during the spring and early summer inside of individual cocoons in natural cavities or provided nest boxes.

During pupation they become dormant until late summer when they resume development and become adults. As adults they enter a second dormancy and overwinter in this stage. Both dormancies are characterized by decreased metabolic activity. We used mRNA sequencing to create a developmental timescale of gene expression at 11 time points as larva pupate and then initiate, maintain, and terminate both pupal and overwintering dormancy.

We used differential gene expression analysis to identify gene expression profiles associated with the metabolic shift at the initiation and termination of dormancy, and a profile that is consistent during the maintenance phase. We compare gene expression and identify similarities between the pupal and adult overwintering dormancies.