Orcokinin neuropeptides regulate ecdysis in the hemimetabolous insect Rhodnius prolixus

To grow and develop insects must undergo ecdysis. During this process, the individual sheds the old cuticle to emerge as the following developmental stage. During ecdysis, different programed behaviors are regulated by neuropeptidergic pathways. In general, components of these pathways are better characterized in crustacean and holometabolous insects than in hemimetabola. In insects, the orkoninin gene produces two different neuropeptide precursors by alternative splicing: orcokinin A and orcokinin B. Although orcokinins are well conserved in insect species, their physiological role remains elusive. Here we describe a new splicing variant of the orcokinin gene in the hemimetabolous triatomine Rhodnius prolixus. We further analyze the expression pattern and the function of the alternatively spliced RhoprOK transcripts by means of immunohistochemistry and RNAi-mediated gene silencing. Our results indicate that orkoninis play an essential role in the peptidergic signaling pathway regulating ecdysis in the hemimetabolous insect Rhodnius prolixus. [Display omitted] •RhoprOKC is a new isoform of RhoprOK gene.•The expression pattern of the three isoforms of the gene was studied in central nervous system and periphery.•RNAi showed that RhoprOKA peptides are key regulator of ecdysis in Rhodnius prolixus.•RhoprOKB type peptide are also involved in regulating ecdysis but less critically than RhoprOKA.•RhoprOKs does not regulate ecdysteroidogenesis.