Comparative Study of Neuropeptides from the Corpora Cardiaca of Solitary and Gregarious Locusta

Neuropeptide content of the corpora cardiaca (CC) was studied in crowded (gregarious phase) and isolated (solitary phase) Locusta migratoria migratorioides adults, using electrophoretic, chromatographic, and immunological techniques. Quantitative differences were found in the three neuropeptides investigated (neuroparsins, Lom-OMP, and APRP). The amount of neuroparsin A was higher in the CC of crowded locusts. Neuroparsin B content of the CC was quite similar in isolated and crowded locusts, or in some cases slightly higher in the latter. The comparative amounts of the ovary maturating parsin, Lom-OMP, in the CC were dependent on the sexual maturation of the locusts, being nearly similar in maturing isolated locusts and immature crowded locusts, but higher in crowded locusts when both phases were completely mature. The amount of AKH-precursor related peptides (APRP) was markedly and consistently higher in the CC of isolated locusts. These findings are discussed in relation to other physiological and ecological phase-dependent differences in locusts.