Think dating is hard in the human world?
Spare a thought for Macrostomum hystrix, a microscopic flatworm that has evolved an odd method of self-impregnation so it can procreate under conditions of low mate availability.
In normal circumstances, the flatworm exchanges sperm with others of its kind using a needle-like stylet that pierces the other worm’s outer membrane – a process known as “traumatic insemination”.
But when partners are scarce, the worms are able to turn their stylets into themselves, allowing them to fertilise their own eggs and reproduce.
This is all possible because the flatworms are hermaphrodites, with both male and female reproductive organs.
"As far as we know, this is the first described example of hypodermic self-injection of sperm into the head,” says lead author of the study Dr Steven Ramm from the University of Bielefeld.
“To us this sounds traumatic, but to these flatworms it may be their best bet if they cannot find a mate but still want to reproduce.”