Concurrent Effects of Light and Eyestalk Extract on Brain, Thoracic Ganglion and on the Changes in the Gonadal Indices of Female Crab, Paratelphusa hydrodromous (Herbst)

Three types of neurosecretory cells, (A, B & C) were identified in the brain and four types of neurosecretory cells (A, B, C & D) in the thoracic ganglion of P. hydrodromous. Continuous exposure to light for 15 days triggered the secretory activity of the neurosecretory cells and increased the gonadal indices. While saline treatment potentiated the light mediated effect, injection of the eyestalk extract inhibited the effect of light. Results of this preliminary study suggest that eyestalk hormones regulate the effect of light on ovarian development in P. hydrodromous.