Transcriptome analysis of Drosophila suzukii winter and summer morphs identifies differences in olfactory related genes

Drosophila suzukii (Matsumura) is a major economic pest in Europe and North America that oviposits in ripening raspberries, strawberries, blueberries, and cherries, thereby potentially damaging an entire harvest or rendering a harvest unfit for sale or export. D. suzukii exhibits two distinct morphs: a summer morph and a winter morph. Although the winter morph allows this invasive pest to survive in temperate climates, winter is still a natural population bottleneck. Monitoring early spring populations is important for accurate population forecasts; thus, understanding the biology of the larger and darker winter morphs may aid in the development of IPM programs. In this study, transcriptome analysis of the head regions of winter and summer morphs showed significant differences in 738 genes (p≤0.0001). Among these genes, ten olfactory related genes were identified. Several of these genes have been shown to play a role in the location of food sources and in mating behavior. Understanding these genes may be crucial to explaining the failure of monitoring traps during winter. Behavioral inferences from differences in gene expression could improve the lures used in winter months, and improved traps would lead to more accurate estimates of overwintering D. suzukii populations. A better understanding of winter morph physiology and behavior would assist in formulating direct control methods and developing better monitoring tools.