Flies In Danger Escape With Safety Dance High-speed cameras reveal that flies perform an elegant little ballet with their legs. In less than a 10th of a second, flies perceive the direction of the threat and use their legs to angle their bodies for the quickest escape route.

Flies In Danger Escape With Safety Dance

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This may not be quite as important as your kids' education but it sure can be irritating, and scientists in California have made a major advance in a historic battle - the never-ending battle of man versus fly. Using sophisticated imaging techniques they have analyzed how a fly escapes being swatted.

Not only does this news give us humans a crucial piece of intelligence for modifying our swatting strategy, it also tells us that a fly's brain is pretty amazing. NPR's Joe Palca has more.

JOE PALCA: There's probably no one in the world better to answer the question of how to swat a fly than Michael Dickinson.

MICHAEL DICKINSON: We've always been interested in how flies launch and, you know, how flies fly and how flies land. And this particular study was focusing on takeoff.

PALCA: Specifically, how they take off to avoid a threat, like a rapidly-approaching fly swatter. Dickinson is at Cal Tech, where he has all sorts of sophisticated equipment for following fly flight, including infrared stereoscopic cameras and specialized flight software.

His latest tool is a high-speed video camera capable of shooting 5,400 frames per second.

DICKINSON: By contrast, the standard video records at about 30 frames per second.

PALCA: To study a fly's takeoffs, he first had to get the fly to stand in front of the camera.

DICKINSON: That's actually one of the challenges of this study. And my graduate student, Gwyneth Card, is just a master at fly wrangling.

PALCA: If fly wrangling calls up images of miniature lassos and whips, well, the reality is more prosaic. You chill the flies a bit and then get them to move toward a light, which they apparently like to do.

DICKINSON: So, we were - rather she was able to lure individual flies out onto a little prismatic platform surrounded by a little water moat.

PALCA: The prism in the platform let them see the fly from the bottom and side simultaneously. Once the fly is in the right place, a mini-fly swatter moves toward it.

DICKINSON: What we noticed, because we could use these fancy high-speed video cameras, is before they actually jump, they perform an elegant little ballet with their legs. They move their legs around and they reposition their body so that when they do jump, they will push themselves away from the looming threat.

PALCA: Dickinson says this little ballet is pretty remarkable. In less than a tenth of a second the fly has to perceive the threat using its eyes, determine what direction the threat is coming from, and then make the appropriate movement with its legs so it'll jump in the right direction to avoid the threat.

DICKINSON: When you see a fly flittering around your hair or your potato salad, you know, you might see an annoyance. But in my lab we really see a marvelous machine, arguably the most sophisticated flying device on the planet, and it's all controlled by this brain about the size of a poppy seed.

PALCA: Dickinson's future studies will continue to explore the amazing things a fly brain can do. But for now his study that appears in the journal Current Biology could be helpful to people as they flail away at a fly.

DICKINSON: You shouldn't swat where you see them; you should anticipate that they're going to jump away from you. So you should extend your swat in the direction of the fly's anticipated motion.

PALCA: So people who have this idea that they always jump up are mistaken; they jump away.

DICKINSON: That's correct. However, I didn't enter in this research in order to help people swat flies better. In fact, I rarely swat flies.

PALCA: To each his own, I say.

Joe Palca, NPR News, Washington.

INSKEEP: You can see these elegant little fly ballets in a series of maddening videos at NPR.org.

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