Another strategy, known as sperm partitioning, occurs when males conserve their limited supply of sperm by reducing the quantity of sperm ejected. In "Drosophila", ejaculation amount during sequential copulations is reduced; this results in half filled female sperm reserves following a single copulatory event, but allows the male to mate with a larger number of females without exhausting his supply of sperm. To facilitate sperm partitioning, some males have developed complex ways to store and deliver their sperm. In the blue headed wrasse, "Thalassoma bifasciatum", the sperm duct is sectioned into several small chambers that are surrounded by a muscle that allows the male to regulate how much sperm is released in one copulatory event.