Tissue-specific signatures of diapause in the Asian longhorned beetle using RNA-seq

An insect’s ability to survive low temperatures throughout winter is important for range expansion in temperate regions. To cope with winter stress, many insects enter diapause, a state of developmental arrest that is concurrent with metabolic suppression and increased cold tolerance. Although the physiological changes that occur during diapause are well understood, less is known about the mechanisms that drive these phenotypes and how these processes are partitioned and integrated among tissues. In this study, we measured tissue-specific changes in gene expression during prepupal diapause in the wood-boring, forest pest Anoplophora glabripennis using RNA-seq. We sampled fat body, supraesophageal ganglia, midgut, hindgut, and Malpighian tubules during four phases of diapause development: pre-diapause, diapause maintenance, post-diapause quiescence, and post-diapause larval development. We observed distinct tissue-specific gene expression profiles that shifted upon initiation of diapause and again after diapause termination. During diapause maintenance A. glabripennis increase the abundance of genes involved in the heat shock response, insulin signaling, and epigenetic modification. Tissue-specific characterizations of the diapause phenotype in insects are rare, so these data will aid in increasing the resolution at which we understand the mechanisms governing diapause development.