Abstract
Impregnation of females (i.e., spermatophore transfer) is known to occur soon after ecdysis in closed thelycum penaeids, while no sign of female maturation is visible yet. The influence of impregnation on maturation, spawning, and intermoult duration was assessed in Penaeus indicus females with or without unilateral eyestalk ablation. Impregnation, when occurring in unablated females, was found to significantly increase the percentages of maturing females (93β100% vs. 40β47%) and spawning females (86β100% vs. 20%), the number of spawns per female (1.46β1.91 vs. 0.26β0.40), and the intermoult duration (13.16β13.53 vs. 11.36β11.86 days). No remnants of impregnation was detected since its effects on the various parameters studied were restricted to the moult cycle where it occurred. Unilateral eyestalk ablation induced effects similar to those of impregnation on the reproduction parameters studied, but did not extend the length of the moult cycle. Impregnation of females that have been previously unilaterally ablated induced no change in any parameter studied including the intermoult duration. These findings suggest that impregnation interacts with certain physiological processes controlled by the X organβsinus gland neuroendocrine complex, located in the eyestalk. Β© 1994 WileyβLiss, Inc.