POSTCOPULATORY SEXUAL REFRACTORINESS IS MAINTAINED UNDER THE CONTROL OF THE TERMINAL ABDOMINAL-GANGLION IN THE MALE CRICKET GRYLLUS-BIMACULATUS DEGEER

The location of the center that controls the change underlying mating termination and subsequent sexual refractoriness was investigated in t he male cricket Gryllus bimaculatus DeGeer. In intact males, hooking m ovements of the genitalia did not recommence after the spermatophore w as extruded during copulation, while other copulatory movements such a s body thrusting and cereal vibration recommenced under the female, In males with the connectives cut anywhere between the brain and the ter minal abdominal ganglion (TAG) immediately after spermatophore extrusi on, hooking movements were no longer elicited by artificial stimulatio n of the abdominal tergites and cerci, while other copulatory movement s were still evoked, The isolated adbomen containing 5 ganglia, or eve n only the TAG showed a time-fixed (about 50 min) sexually unresponsiv e state when separated immediately after spermatophore protrusion (new spermatophore formation), TAG-separated males all recommenced courtsh ip and copulation attempts many hours or days after the operation, Spe rmatophores in pre-copulatory operated males were spontaneously extrud ed some time after operation, They showed copulatory movements to arti ficial stimulation of the tergites but no further hooking movements, I ntact males paired with uncopulatable females, whose genital chambers were closed with wax, entered the sexually refractory stage 1-3 times within 5 h through abnormal self-spermatophore extrusion, while TAG-se parated males did not, and remained permanently sexually receptive to females. Pre-copulatory males exhibiting spermatophore extrusion durin g cryogenic inactivation of the connectives were all in the sexual ref ractory stage when they recovered. These results suggest that the swit ching and timer functions underlying the male reproductive cycle are c ontained in the TAG.