NEUROENDOCRINE CONTROL OF REPRODUCTION IN THE MALE FRESHWATER CRAB, BARYTELPHUSA GUERINI (H. MILNE EDWARDS) (DECAPODA : POTAMIDEA)

The newroendocrine Control of male reproductive system was studied in the crab, Barytelphusa guerini. Bilateral eyestalk extripation in adult animals in the post reproductive season led to an increase in the size of reproductive system and testicular weights followed by an increase in diameter of seminiferous tubules, number of cells per tubule, diameter of vas deferens and wall thickness of Vas deferens. Injection of eyestalk extracts into the ablated animals prevented this accelerated growth almost completely, but sinus gland injections resulted only in partial inhibition. Brain and thoracic ganglionic mass extracts did not prevent the accelerated growth Injection of eyestalk and sinus gland etracts into the normal animals resulted in a slight inhibition of the reproductive system. Whip central nervous extract injections led to a slight acceleration of the same. However, the changes obtained were not much significant. Central nervous extracts from 20 days old eyestalk ablated animals injected into normal animals caused a slightly significant increase in the reproductive system. The male reproductive system was suggested to be under the dual control of the neuroendocrine hormones, a gonad inhibiting factor from the eyestalks and a gonad stimulating factor from the central nervous structures. The reproductive activity was suggested to be dependent on the variations in the relative concentrations of these two antagonistic hormones, during the different phases of reproductive activity.