The decapod red pigment-concentrating hormone (Panbo-RPCH) is the first identified neuropeptide of the order Plecoptera and is interpreted as homoplastic character state

• Panbo-RPCH is present in Plecoptera (two species), and in Lycidae (Coleoptera).
• This octapeptide member of the AKH/RPCH family was sequenced by LC-ESI–MS.
• Panbo-RPCH is not present in basal orders of crustaceans and insects.
• Current distribution of Panbo-RPCH in Crustacea–Hexapoda clade is homoplastic.

This paper presents the first neuropeptide structure, identified by mass spectrometry, in two species of Plectoptera (stoneflies) and in one species of the coleopteran family Lycidae. In all three species, the octapeptide Panbo-RPCH (first identified in Pandalus borealis as a red pigment-concentrating hormone: pGlu-Leu-Asn-Phe-Ser-Pro-Gly-Trp amide) is present. A review of the literature available on invertebrate neuropeptides that are identified or predicted from expressed sequence tags, transcriptome shotgun assemblies, and from fully sequenced genomes, show that Panbo-RPCH is found in Malacostraca (Crustacea) and certain hemipteran Heteroptera (Insecta). To date, Panbo-RPCH has not been shown present in non-Malacostracan crustaceans, nor in basal taxa of the Insecta (Archaeognatha, Zygentoma, Ephemeroptera, Odonata). The present data adds to knowledge on the distribution of Panbo-RPCH, and when taking into account the most accepted, current phylogenetics of the Crustacea–Hexapoda relationship, this distribution of Panbo-RPCH in Malacostraca, Plecoptera, some hemipteran Heteroptera and in Coleoptera (Lycidae) can best be explained by homoplasy, implying parallel evolution.