Adult Fly Copulation The female fly typically only mates once during her life, thus she considered monogamous. The sperm received from the male fly during their only copulation moves into a storage area located in the female fly's reproductive system called the spermatheca. This sperm storage area is accessed repeatedly by several batches of eggs that the female lays throughout her lifetime as the eggs pass down the oviduct. The male fly has genitalia located on its posterior.