Your average sexual species is around one or two million years old. Asexual species, on the other hand, rarely get to celebrate beyond their one hundred thousandth birthday. Or, at least, that’s the theory. The trouble is there are a bunch of all-female species that have flagrantly ignored their shelf-life predictions. These ‘evolutionary scoundrels’, as the legendary biologist John Maynard Smith has described them, have caused no end of scientific fluster, calling into question the whole question of sex.
