HORMONAL CONTROL OF REPRODUCTION IN THE SHRIMP METAPENAEUS AFFINIS

The role of eyestalk, brain and thoracic ganglionic hormones on oogenesis and spermatogenesis of the maine shrimp, Metapenaeus affinis has been worked out. Eyestalk ablation in immature prawns, nearing adult size showed rapid development of ovaries, suggesting that eyestalks produce ovarian inhibitory principle. Eyestalks played similar role in male prawns. Brain and thoracic ganglionic extract injuctions changed the colour of the ovary from white to dark green, enhanced the ovarian index, and the previtellogenic oocytes undergoing vitellogenesis. In the males, the testicular follicular diameters were increased and they were filled with spermatozoa. This gives evidence, that gonad stimulatory principle(s) is fabricated by brain and thoracic ganglia neurosecretory cells