Submitted to: Journal of Insect Morphology and Embryology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/1997
Publication Date: N/A
Citation: N/A Interpretive Summary: The process of metamorphosis (shedding the skin) is required by insects in order to transform from larvae into adults. Insect metamorphosis requires hormones in order to achieve the adult form. These hormones, called ecdysones in insects, are manufactured by tissues that must be signalled by chemicals from the brain, to produce the ecdysones at the proper time. These signalling compounds are called ecdysiotropins. In this article, we describe the location of nerve cells producing one of these ecdysiotropins in a moth and, in doing so, found that in addition to stimulating the completion of the male reproductive system, the compound is also found in areas of the brain forming the adult eyes and antennae. Thus, this compound appears to have a much larger impact on adult metamorphosis than previously known.
Technical Abstract: Antiserum against testis ecdysiotropin, a peptide required by immature moths to initiate production of testes ecdysteroid, was used to determine the site of synthesis and storage of this peptide. Testis ecdysiotropin was found in neurons of the protocerebrum and optic lobe as well as in nerve tracts extending through the optic lobe, subesophageal ganglion and thoracic ganglia. Intrinsic cells in the thoracic and abdominal ganglia also contained material reactive to this antiserum. Testis ecdystiotropin antiserum also detected accumulation of this peptide between the inner and outer testis sheaths of pupae. The localization of abundant cells and nerve fibers in the optic lobe of the pupa, as well as in imaginal discs of the last instar, indicate that testis ecdystiotropin has a much larger impact on adult metamorphosis than development of the reproductive system and initiation of gametogenesis. This peptide may also initiate a cascade of activity required for the development of much of the adult nervous system.