A novel myotropic peptide was isolated from an extract of 10,000 heads of adult Leptinotarsa decemlineata by means of high performance liquid chromatography (HPLC). The peptide stimulates the contractions of the oviduct of Leptinotarsa as well as that of Locusta migratoria. Gas phase sequencing and comparison of candidate synthetic peptides in the amide and acid form revealed the following primary structure: Ile-Ala-Tyr-Lys-Pro-Glu-NH2. This new peptide has a molecular weight of 720 Da and has been named Led OVM. Led OVM does not exhibit significant sequence homology with any known vertebrate or invertebrate peptide. Sixteen additional myotropic factors were also separated by means of HPLC, but were as yet not recovered in amounts large enough for them to be sequenced.