09 April 2011

H for Hermaphroditic Worms

This post is brought to you by the letter H.

Warning: This post is about science writing! It's also about reproductive habits of worms! I think you may like it, but if you are offended by these things...you've been warned.

Why care about hermaphroditic worms? It can show you what happens when both sexes are in one body in a species. (Hint: it's not pretty.) I'm writing about it because it's the topic of an article written by a science writer who spoke to my graduate science-medical writing class.

Susan Milius is a writer at Science News. Susan is a hilarious and engaging speaker, besides being a great writer. One of the pieces she talked briefly about hermaphroditic worms who engage in "penis fencing" to determine which will become impregnated.

Penis fencing.

I wanted to repeat that in case you missed it the first time.

If I had a phrase like that, I would want to use it. (In fact, I just did. Twice.) But in Susan's 2006 article Battle of the hermaphrodites: sexes clash even when sharing the same body, she only used it once (that I counted). I imagine that must have been a heroic display of self-control.

These hermaphroditic worms are both male and female in one body, and they can both fertilize another worm and receive sperm for fertilizing eggs within their own body. But before you ask if one can fertilize itself, check out this description of Pseudobiceros bedfordi (flatworms) coupling from Susan's article:

"When two of these small, speckled sea worms meet to mate, there's no taking turns. Each worm, 2 to 6 centimeters long, wields its pair of side-by-side penises like a weapon. One worm tries to fertilize the other by ejaculating anywhere on its partner's body, splashing it with sperm in a cocktail that dissolves flesh. After the brew eats a hole through the skin, the sperm work their way through various tissues until they reach the eggs."
Horrifying. And the penis fencing (that's three) is almost more horrifying. This example was observed in the Pseudoceros bifurcus marine worm.

"When potential mates meet, they rear up and face off, feinting and dodging.
The researchers argued that each worm was trying to fertilize the other's eggs while minimizing the sperm it receives. A worm delivers its sperm by using its penis to punch a hole in the partner's skin, anywhere on the body. As in the ejaculate-splashing polyclad worms, the sperm's navigational prowess gets it to the eggs."
I'm wrapping up now so I don't get carried away about the sciencey stuff for another 500 words. You can read Susan's article if, like me, you're intrigued by this research.

I'm just glad I'm not a hermpahroditic worm. No, thanks!

Now You!
Would you show restraint or go wild in your article if you were handed a phrase like "penis fencing" on a silver platter?


And that's 4 for me. I wanted to put it in the title, but I showed some restraint.