Identification of the gregarization-associated dark-pigmentotropin in locusts through an albino mutant

In response to crowding, locusts develop characteristic black patterns that are well discernible in the gregarious phase at outbreaks. We report here a dark-color-inducing neuropeptide (dark-pigmentotropin) from the corpora cardiaca of two plague locusts, Schistocerca gregaria and Locusta migratoria, The chromatographic isolation of this neuropeptide,vas monitored by using a bioassay with an albino mutant of L. migratoria. The neurohormone, consisting of 11 amino acids, is identical to [His(7)] corazonin, previously isolated front corpora cardiaca of another acridid without known function. The present results show that even in isolated (solitary) nymphs, [His(7)] corazonin induces gregarious black patterns, Its primary structure shows some similarity with the vertebrate melanophore stimulating hormone.