Evidence for the involvement of selected biogenic amines (serotonin and melatonin) in the regulation of molting of the edible crab, Oziotelphusa senex senex Fabricius

In the present study, we examined the role of serotonin and melatonin on molting of the fresh water edible crab, Oziotelphusa senex senex. Administration of melatonin (10− 7 mol/crab) into intact crabs induced precocious molting in a 28-day experimental period. Injection of serotonin (10− 6 mol/crab) into intact crabs did not result in any change in molting. Significant increase in the weights of the mandibular organs (28.81%) and the Y-organs (42.57%) was observed in melatonin injected intact crabs when compared with control crabs. Bilateral eyestalk ablation (ESX) significantly increased the weights of mandibular organs (32.71%) and Y-organs (48.21%) when compared with intact crabs over a period of 28-days. However, injection of serotonin or melatonin into ESX crabs did not show much variation in the weights of the mandibular organs and the Y-organs when compared with ESX crabs without biogenic amines injections. These results provide the first evidence that melatonin is involved in the control of regulation of growth in a crustacean.