#WeirdAnimalWednesday: This Worm Injects Sperm Into its Own Head

posted: 07/01/15
by: Danny Clemens
Macrostomum hystrix
Lukas Schärer

What do you do when you can't find a date? Most people choose stay home on the couch and destroy a tub of ice cream as they wallow in their loneliness and misery.

When left without a mate, a newly discovered species of flatworm (Macrostomum hystrix) takes matters into its own hands -- so to speak. The hermaphroditic worm can use a special "needle-like male copulatory organ" mounted on its head to inject sperm into the back half of its body, where the sperm will then fertilize the worm's own eggs.

The process is known as "selfing", and was easily observable in M. hystrix thanks to the creature's transparent body. Selfing isn't unheard of in nature, but the flatworm's unique method of injecting sperm is notable:

"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" remarked Dr. Steven Ramm, who penned a new study detailing the worm's bizarre mating habit.

The self-fertilization method isn't perfect -- the resulting offspring are inbred. Ramm notes, however, that inbred offspring are better than no offspring.

Next time you're home alone on a Friday night, just remember: it could be a lot worse.

Click here to read the full study in the journal Proceedings of the Royal Society B

Learn more about worms:


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