Study: Scouting the Olympics of Sperm

More

Longer sperm fare better in the race to fertilization, but speed is actually not a factor.

2959254617_b8e1f396a7_zmain.jpgFlickr

PROBLEM: The fastest Olympic swimmer always gets the gold. If we replace "Olympic swimmer" with "sperm" and "gets the gold" with "fertilizes the egg," does the same hold true?

METHODOLOGY: It's fun to picture how this must have gone down: First, scientists organized male fruit flies into two groups based on similar, and naturally occurring, sperm traits. Then, they mated one fly from each group with the same female. The flies had been genetically modified to produce fluorescent sperm -- one group glowed green, the other, red. This allowed scientists to observe and compare the two groups of sperm "in real time" while they were traveling down the female reproductive tract, to see how competition affected their behavior.

RESULTS: Scientists observed battles between rival sperm in the reproductive tract. Regardless of who got there first, the sperm would wait in a "storage area" until the female released eggs. Each time the female mated, the new sperm would arrive in this area and attempt to force the old sperm out. Longer and slower sperm were better at kicking out the other guys, and they were less likely to be ejected themselves.

CONCLUSION: A sperm's length is positively associated with its likelihood of successful fertilization (which we already knew) -- speed, however, is not an advantage.

The full study, " How Multivariate Ejaculate Traits Determine Competitive Fertilization Success in Drosophila melanogaster," will be published in the journal Current Biology.

Jump to comments
Presented by

Lindsay Abrams is an assistant editor at Salon and a former writer and producer for The Atlantic's Health Channel.

Get Today's Top Stories in Your Inbox (preview)

An Eerie Tour of Chernobyl's Wasteland

"Do not touch the water. There is nothing more irradiated than the water itself."


Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register. blog comments powered by Disqus

Video

Is Technology Making Us Better Storytellers?

The minds behind House of Cards and The Moth weigh in.

Video

A Short Film That Skewers Hollywood

A studio executive concocts an animated blockbuster. Who cares about the story?

Video

In Online Dating, Everyone's a Little Bit Racist

The co-founder of OKCupid shares findings from his analysis of millions of users' data.

Video

What Is a Sandwich?

We're overthinking sandwiches, so you don't have to.

Video

Let's Talk About Not Smoking

Why does smoking maintain its allure? James Hamblin seeks the wisdom of a cool person.

Writers

Up
Down

More in Health

Just In