Hormonal Control of Female Reproduction and Molting in Decapod Crustaceans

Endocrine regulation of reproduction and molting in Crustacea was first demonstrated by the experimental evidence that eyestalk removal led to accelerated ovarian maturation and the onset of precocious molting. Subsequent immunocyto chemical studies as well as HPLC separation of neuropeptides followed by suitable bioassay established the occurrence of two neuropeptides namely gonad inhibiting (GIH) and molt-inhibiting (MIH) neurohormones in the X-organ/sinus gland complex of stalk-eyed malacostracan crustaceans. While the molt promoting hormones have been decidedly shown to be the ecdysteroids, as in other arthropods, many hormonal factors of diverse chemical nature have been proposed for controlling female reproduction. Neurosecretory hormones from brain/thoracic ganglia, methyl farnesoate, a structural homologue to insect Juvenile hormone III (JH III) and a variety of steroidal hormones are the principal candidates for control of female reproduction, especially viteilogenesis. As molting continue to occur in the adult crustaceans, hormonal coordination of both molting and reproduction becomes vital to accomplish fast body growth and increased fecundity in these aquaculture-targeted arthropods. Steroidal control of such a coordination is stressed in this review.