Sex – it’s essential to life on Earth, and a pretty fun thing to do on a rainy day. Sexual techniques vary across the spectrum of living things, but one thing is certain: Reproduction requires male and female components. Anything else, after all, is just self-amusement. However, scientists at the Universities of Basel and Bielefeld have discovered a flatworm that takes masturbation to a whole other level: When separated from mating options, the Macrostomum hystrix can reproduce by inseminating itself. By stabbing itself in the head. With its own penis.
“Lots of animals are able to self-fertilize, but this is the first example of one that uses a hypodermic appendage to do so,” Dr Steven Ramm, the lead author, told The Guardian. “Snails can fertilize themselves, but they have connections between the male and female organs. In these worms, male and female organs are kept separate, so they need this system for fertilization to work.”
Hermaphrodites, or organisms that possess both male and female sex organs, aren’t particularly rare. But, as Dr Ramm explained, most hermaphrodites have a more sophisticated system for self-reproduction.
Possessing both sets of sex organs is actually a survival strategy. Even among hermaphrodites, mating with another specimen is preferred to self-insemination from a genetic diversity standpoint. However, mates aren’t always around, in which case most organisms would find their reason for existing terminated – they would never have the chance to pass on their genes.
Hermaphrodites, on the other hand, have the option of doing the deed themselves. Of course the offspring would be inbred by the most literal definition of the word, but they would then at least have the chance to go forth and share their genes with other organisms who, presumably, are not themselves.
“As far as we know, this is the first described example of hypodermic self-injection of sperm into the head. 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” explains Dr Ramm.
Any offspring, it would seem, is better than no offspring.