NERVOUS CONTROL OF OVULATION AND EJACULATION IN HELIX ASPERSA

The ovotestis duct transports male and female gametes from theovotestis, through the seminal vesicle, and into the fertilizationpouch-spermathecal complex. All these structures are innervatedby small branches of the intestinal nerve. Electrical stimulationof the nerve increased the rate at which gametes were transportedin the duct and caused autosperm to flow into the fertilizationpouch-spermathecal complex. These events were accompanied bystimulation-induced peristaltic contractions along the ductand activation of the cilia lining the interior of the duct.Acetylcholine and serotonin were identified as excitatory transmittersin this system, while FMRFamide was identified as a muscle relaxant.The nervous control of ejaculation may contribute to optimizingthe size of the ejaculate in a context of sperm competition,while the involvement of the nervous system in ovulation maystem from a requirement for sensory integration that is peculiarto the Stylommatophora. (Received 16 December 2004; accepted 31 March 2005)