The fight for the egg - female mice block competing sperm

Fast and efficient sperm increases a male’s chance of fathering a female’s offspring. But it also increases the chance of several sperm fertilizing the same egg, which usually results in an egg that doesn’t develop.

How can females avoid that risk? Researchers from the University of Western Australia have, for the first time, shown that females change their reproductive phenotype in response to environmental pressure.

The group studied mice from two natural populations of different sperm competitiveness. Females facing higher sperm competition produced eggs that were harder to fertilize than those from females of the control group.

Read more at University of Western Australia