Flatworm uses 'hypodermic penis' to inject sperm into own head

Hermaphrodite flatworm is able to self-fertilise thanks to an evolutionary development resulting in a needle-like penis, scientists have discovered

The pursuit of reproductive success in the animal kingdom sometimes calls for extreme measures. But few creatures can match the hermaphrodite flatworm, which scientists have discovered can reproduce by injecting sperm into its own head.

The tiny aquatic worm, Macrostomum hystix, is able to self-fertilise because it produces both eggs and sperm. Although it prefers to reproduce with other flatworms, when no mating opportunities are present it resorts to using its needle-like penis to inject sperm into its own head.