Nature and biosynthesis of ommochromes in Locusta migratoria cinerascens Fabr. (Orthoptera, Acrididae) and its albino mutant.

The identification and localization of the 4 ommochromes present in locust body were established. 2 new chemical species were isolated: acridiommatins 1 (under crystalline form) and 2 (perhaps a xanthommatin ester). The course of their biosynthesis was studied with 2 different methods: quantitative analysis of the ommochrome content in organs during the 2 last larvel instars and the whole imaginal life and measurement of the tryptophan pyrrolase activities during the same period in the normal strain and in an albino mutant strain. With these 2 methods a cyclic activity related to the moulting cycle was found in the ommochrome pathway without any notable difference beween the 2 strains.