Growth of axon collaterals of eclosion hormone neurons into a new release site during metamorphosis of Bombyx mori.

Eclosion hormone (EH) is a peptide triggering ecdysis in insects. Injection of Lucifer dye into EH producing cells in the silkworm at various stages of adult development revealed that after pupation the EH cells produced many axon collaterals to form a new neurohaemal structure in the corpora cardiaca (CC), the corpora allata and the associated nerves of the CC. The axon collaterals may serve as a major release site of EH at adult ecdysis.