Analysis of Transcriptome Difference between Blood-Fed and Starved Tropical Bed Bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae).

The reference transcriptome for Cimex hemipterus (tropical bed bug) was assembled de novo in this study, and differential expression analysis was conducted between blood-fed and starved tropical bed bug. A total of 24,609 transcripts were assembled, with around 79% of them being annotated against the Eukaryotic Orthologous Groups (KOG) database. The transcriptomic comparison revealed several differentially expressed genes between blood-fed and starved bed bugs, with 38 of them being identifiable. There were 20 and 18 genes significantly upregulated in blood-fed and starved bed bugs, respectively. Differentially expressed genes (DEGs) were revealed to be associated with regulation, metabolism, transport, motility, immune, and stress response; endocytosis; and signal transduction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed an enrichment of genes encoding steroid biosynthesis, glycosaminoglycan biosynthesis, butanoate metabolism, and autophagy in both blood-fed and starved bed bugs. However, in blood-fed bed bugs, genes involved in histidine metabolism, caffeine metabolism, ubiquinone/terpenoid-quinone biosynthesis, and sulfur relay system were enriched. On the other hand, starvation activates genes related to nicotinate and nicotinamide metabolism, fatty acid elongation, terpenoid backbone biosynthesis, metabolism of xenobiotics by cytochrome P450, riboflavin metabolism, apoptosis, and protein export. The present study is the first to report a de novo transcriptomic analysis in C. hemipterus and demonstrated differential responses of bed bugs in facing blood-feeding and starvation.