RNA-Seq reveals large quantitative differences between the transcriptomes of outbreak and non-outbreak locusts

Outbreaks of locust populations repeatedly devastate economies and ecosystems in large parts of the world. The consequent behavioural shift from solitarious to gregarious and the concomitant changes in the locusts’ biology are of relevant scientific interest. Yet, research on the main locust species has not benefitted from recent advances in genomics. In this first RNA-Seq study on Schistocerca gregaria, we report two transcriptomes, including many novel genes, as well as differential gene expression results. In line with the large biological differences between solitarious and gregarious locusts, almost half of the transcripts are differentially expressed between their central nervous systems. Most of these transcripts are over-expressed in the gregarious locusts, suggesting positive correlations between the levels of activity at the population, individual, tissue and gene expression levels. We group these differentially expressed transcripts by gene function and highlight those that are most likely to be associated with locusts’ phase change either in a species-specific or general manner. Finally, we discuss our findings in the context of population-level and physiological events leading to gregariousness.M. Bakkali wishes to thank the Spanish Ministerio de Ciencia y Tecnología for the for the Ramón y Cajal fellowship and for the BFU2010-16438 grant that supported both this research and the FPI studentship to Rubén Martín Blázquez. We thank Mrs. Pernille Lavgesen for revision of the English language writing of this manuscript. We also thank the editor for the valuable comments on the manuscript