When it comes to peculiar penises, there’s no shortage in the animal kingdom. Just last month DISCOVER blogger Carl Zimmer documented new research into why many male ducks have such an extravagant spiral-shaped phallus. This week, in a paper (in press) in the Proceedings of the Royal Society B, the study of goofy genitalia follows fruit flies.

The male fruit fly has a penis that resembles a medieval weapon, dotted with hooks and spines. Are those barbs there to remove rival sperm, or pierce the female’s genital tract to allow sperm a shortcut, or something else? There was one way to find out: lasers.

Scientists used lasers to shave the extra equipment off male fruit flies’ penises and set them free to try to mate. And, as it turned out, the hooks and spines simply help a male hang onto a female for the whole 10 minutes it take them to mate; without them, he didn’t do so well. From “Not Exactly Rocket Science”:

They found that a partial shave did nothing, but the full treatment significantly reduced the odds of the males mating with females. With the spines, they were virtually guaranteed to mate if a female was around; without them, their chances fell to around 20%. It wasn’t for lack of trying either – all of the shorn males tried to woo a female and almost all tried to mate. They simply failed. They did all the right things – mounting, placing their genitals in the right place – but it was for nought. And if the spineless males were placed in direct competition with a normal one over a female, they almost always lost.

Related Content:
Discoblog: The Strange, Violent Sex Lives of Fruit Flies & Beeltes
80beats: Meet the Sexually Irresistible Fruit Fly
The Loom: Kinkiness Beyond Kinky

Image: Wikimedia Commons / André Karwath