A novel member of the adipokinetic peptide family in a “living fossil”, the ice crawler Galloisiana yuasai, is the first identified neuropeptide from the order Grylloblattodea

This is the first report on the structural identity of a neuropeptide of the insect order Grylloblattodea. A peptide was isolated and sequenced from the retrocerebral corpora cardiaca–corpora allata complex of the ice crawler, Galloisiana yuasai. The sequence of the peptide was deduced from the multiple MSN electrospray mass data as that of an octapeptide: pGlu-Val-Asn-Phe-Ser-Pro-Thr-Trp amide. The retention time on reversed-phase HPLC and the CID MS2 mass spectra of a synthetic peptide with the same primary structure were exactly the same as of the natural peptide. The sequence represents a novel peptide of the adipokinetic hormone family which contains presently 50 members. The primary structure differs in only one position to a few previously discovered AKHs. A scenario is outlined that makes it likely that the most recently discovered insect order, the Mantophasmatodea, and the Grylloblattodea are closely related.