Structural data on hypertrehalosaemic neuropeptides from Cryptocercus punctulatus and Therea petiveriana: How do they fit into the phylogeny of cockroaches?

Hypertrehalosaemic neuropeptides from the corpora cardiaca of the cockroaches Cryptocercus punctulatus and Thera petiveriana were structurally analysed to gather phylogenetic information independent from that provided by morphoanatomical data. Isolation of the peptides by liquid chromatography and structural elucidation by Edman degradation and mass spectrometry revealed an identical octapeptide for both species: pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2. This peptide, denoted Tem-HrTH, was previously found in tenebrionid beetles and in the cockroach Polyphaga aegyptiaca. Using this information for phylogenetic analysis yielded a peptide tree that supports the previous morphoanatomical data and thus places the woodroach Cryptocercus inside the cockroach subfamily Polyphaginae.