NERVOUS CONTROL OF OVULATION AND EJACULATION IN HELIX ASPERSA

The ovotestis duct transports male and female gametes from the ovotestis, through the seminal vesicle, and into the fertilization pouch-spermathecal complex. All these structures are innervated by small branches of the intestinal nerve. Electrical stimulation of the nerve increased the rate at which gametes were transported in the duct and caused autosperm to flow into the fertilization pouch-spermathecal complex. These events were accompanied by stimulation-induced peristaltic contractions along the duct and activation of the cilia lining the interior of the duct. Acetylcholine and serotonin were identified as excitatory transmitters in this system, while FMRFamide was identified as a muscle relaxant. The nervous control of ejaculation may contribute to optimizing the size of the ejaculate in a context of sperm competition, while the involvement of the nervous system in ovulation may stem from a requirement for sensory integration that is peculiar to the Stylommatophora.