Premier Presentation: A genomics approach to studying migration in high-flying moth pests

Migration is a fundamental life-history strategy for billions of insects, including many pest species, yet the genes and biochemical pathways that drive this phenomenon are poorly understood. Here, we use a novel combination of tethered flight and next-generation sequencing to determine transcriptome differences associated with flight propensity in a major agricultural pest, the cotton bollworm Helicoverpa armigera. Phenotyping using state-of-the-art flight mills showed that H. armigera display continuous variation in flight performance with individuals capable of flying up to 40 km during a single night. RNA-sequencing of adult moths exhibiting distinct short- and long-distance flight phenotypes revealed a suite of differentially expressed genes with many clearly related to physiological adaptations required for long-distance flight. These include genes important in the mobilisation of lipids as flight fuel, flight muscle structure and the regulation of hormones that influence migratory physiology. We conclude that the ability to express this complex suite of pathways underlines the remarkable flexibility of facultative insect migrants to respond to deteriorating conditions in the form of migratory flight and, more broadly, the results provide novel insights into the fundamental transcriptional changes required for migration in insects and other taxa.