Corn moth parasperm. Coloured transmission electron micrograph (TEM) of a section through parasperm from a corn moth (superfamily Tineoidea), showing flagella, lacinate appendages and mitochondrial derivatives. Parasperm are infertile sperm that can dominate the ejaculate of some insects. It is thought that they enable fertile sperm to survive longer inside the reproductive tract of the female, which contains sperm-killing chemicals. Studies have found that the more parasperm in the ejaculate, the longer the fertile sperm survived.