Development, endocrine organs and moulting in the embryos ofDysdercus cingulatus Fabr (Heteroptera: Pyrrhocoridae)

Abstract

Embryonic development of Dysdercus cingulatus is briefly described. In the embryos, neurosecretory cells become evident in the median, lateral and ventral aspects of protocerebrum 84 hr after egg laying. The corpora cardiaca, the corpora allata and the pro thoracic glands arise more or less simultaneously at 78 hr from the dorsolateral wall of the stomodaeum, from the mandibular segments and from the labial segments respectively. Secretory material appears in the brain neurosecretory cells and in the intrinsic cells of the corpus cardiacum at 84 hr and in the nervi corpori cardiaci and aorta at 90 hr. The cells of the prothoracic glands show signs of secretory activity at 90 hr, reaching maximum activity around 96 hr. The corpus allatum appears to be inactive in the embryo. Two embryonic moults appear between 96 hr and 110 hr. Consequence of events suggests that the neurosecretory material stimulates the prothoracic glands including embryonic moulting.