Females are isolated from males on the day before the experiment, after they are kept with the males for a few days. In the morning at the time when the females usually spawn eggs, the female is anesthetized and then her abdomen is squeezed with fingers gently on a cotton puff soaked in BSS. The collected unfertilized eggs are transferred into a BSS-filled Petri dish using tweezers (to be continued to M4-3b). The suitable method for anesthesia must be used, according to institutional regulations.