Aug 18, 2012

Dragonflies: The Flying Aces of the Insect World


Miles O’Brien: This dragonfly is grabbing the meal on the go.

Stacey Combes: This attempt is so fast that unless we film it in high-speed we can’t see whether it caught the prey. But when it gets back to its perch, if we see it chewing we know that it was successful.

Miles O’Brien: With support from the National Science Fundation, Harvard university biomechanist Stacey Combes, wants to understand how dragonflies pull off these complicated aerial feats; hunting, and even reproducing in midair. She and her team set up their lab near a pond outside Boston, right in the heart of dragonfly country.

Student: All right, I got one. I lost it.

Miles O’Brien: Clearly it's not easy to catch a dragonfly.

Student: I got one.

Miles O’Brien: Check out this frog. In this specially built netted enclosure, Combes’ team set up eight high-speed cameras. Then they release a dragonfly and some tasty fruit fly prey to watch what happens next.

Stacey Combes: They’ll go up in midair, catch the prey with their hands, or with their feet turn upside down and glide back to stick. And the whole capture will take maybe a second, or a second and a half. This one’s missing about half of its left front wing and yet it still does an amazing job catching the fruit fly in midair.

Student: It only takes about half a second for this to happen.

Stacey Combes: They caught, you know, about 90 or 95 percent of the prey that we gave them. And interestingly, they’re one of the most ancient groups of insects. They’ve had a long time to evolve their skills as predators.

Miles O’Brien: About 300 million years. These four-winged insects predate dinosaurs. They can fly straight up, straight down, hover like helicopters, and disappear in a blur. And their eyesight?

Amber DesLauriers: Almost its whole head is eye.They can see pretty much all the way around their head, except right behind them.

Miles O’Brien: Dragonflies mate and lay eggs in flight.

Stacy Combes: Do you see her like just dipping in the water?

Student: She’s trying to lay eggs; the male’s trying to mate with her.

Miles O’Brien: Combes says engineers are looking to the dragonfly for inspiration in small scale aircraft design.

Stacy Combes: There's a lot of interest in building, you know, robotic, smaller robotic devices.

Miles O’Brien: And she says better understanding of dragonflies could lead to more effective mosquito control strategies.

Stacy Combes: They may consume 30 mosquitoes a day. They could even consume hundreds a day.

Miles O’Brien: And that’s an idea that could really take flight.

Miles O’Brien: For Science Nation, I’m Miles O’Brien.

Discovery Files: Slow V. Go!

Slow V.[1] Go!

Michigan State University researchers show that more adaptable bacteria that are oriented toward long-term improvement prevailed over competitors that held short term advantages.

Credit: NSF/Karson Productions

Audio Transcript:

Take Your Time -- It's Evolution.

I'm Bob Karson with the discovery files -- new advances in science and engineering from the National Science Foundation.

An evolutionary study of generations of bacteria reads a lot like the fable, 'the tortoise and the hare.'[2] Led by the University of Michigan, it showed that if you're a bacteria, sometimes it's better to be a slow, adaptable tortoise than a fitness-oriented hare.

In the fable, the hare is all like full of himself and instantly gets way out front. So far ahead, he figures he can take a nap. By the time he wakes up, the tortoise is plodding across the finish line.

How does that relate to bacteria? The MSU study recorded evolutionary change over an unprecedented 52,000 generations of bacteria grown over 25 years. The team was able to clone two distinct lineages from a population of frozen E. coli[3]. Welcome to bacterial family feud! And here we go!

One lineage makes a mutational move early in the game that gets them ahead initially, but closes off certain routes for later improvement and eventually winds up extinct. The other lineage is less fit early on, but over the course of several evolutionary moves, produces more beneficial mutations, overcoming its short-term disadvantage. By maintaining greater potential for further adaptation, the tortoises prevail.

Turtle power!

"The Discovery Files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.
[1] Slow V.
“Slo-V” is a slow flying model aircraft. For more information, please visit

[2] the tortoise and the hare
it is a fable attributed to Aesop. The story concerns a hare who ridicules a slow-moving tortoise and is challenged by him to a race. The hare takes a nap midway through the course. When he awakes, he finds that the tortoise has won the competition.

[3] E. coli / Escherichia coli
A bacterium commonly found in the intestines of humans and other animals, where it usually causes no harm. Some strains can cause severe food poisoning, esp. in old people and children. 大腸桿菌

Aug 7, 2012

Curiosity Has Landed on Mars


Things are looking good. Coming up on entry.

Vehicle reports entry interface.

We're beginning to feel the atmosphere as we go in here. Alright, it is reporting that

we are seeing G's on the order of 11 or 12 Earth G's.

Bank reversal 2 is starting (cheering). We are now getting telemetry from Odyssey.

We should have parachute deploy around Mach 1.7.

Parachute has deployed (cheering).

We are decelerating.

Heat shield has separated, we are locked on the ground.

We're down to 90 meters per second at an altitude of 6.5 kilometer descending.

Standing by for backshell separation.

We are in powered flight (cheering).

We're at an altitude of 1 km descending.

Standing by for sky crane. Sky crane has started

Signal from Odyssey remains strong.

Touchdown confirmed. We're safe on Mars (loud, sustained cheering).

We got thumbnails (cheering).

Aug 2, 2012

What's Up for August 2012?


What's Up for August? View Mars as the rover Curiosity lands on its surface this month.

Hello and welcome. I'm Jane Houston Jones at NASA's Jet Propulsion Laboratory in Pasadena, California.

On August 5 at 10:31 p.m. Pacific time NASA's Mars rover named Curiosity will touch down in Gale Crater. The best time to view Mars this month is right after sunset. Saturn, Mars and the bright star Spica [1] form a trio almost all month long. Look low in the west, 30 degrees above the horizon. You should be able to see the difference in color between the three. Saturn appears golden. Spica is blue-white. And Mars is rusty red.

On the 21st the moon joins the lineup.

On the night of the 5th, Mars sets a few hours after sunset everywhere in the U.S.
You can find a Mars viewing party on this night by checking with your local planetarium, science center or astronomy club. If you get a chance to view Mars through a telescope on that night, you might be able to see the dark Martian feature called Syrtis Major [2] near the center of the planet.

Although you can't see Gale Crater, Curiosity's landing site, through the telescope, it's near the limb to the east of Syrtis Major that night.

On the opposite limb is the rover Opportunity, who's been exploring Mars since 2004.
The most popular meteor shower of the year, the Perseids [3], peaks on a summer weekend Saturday night through Sunday morning, August 11th and 12th.

The constellation Perseus [4] rises in the northeast soon after sunset. Just follow the Milky Way from the south to the north to find it.

You'll see dozens of fast, bright meteors, some leaving persistent trains or smoky trails.

You can find information about Curiosity's landing at and And look for MarsCuriosity on Twitter and Facebook.

You can learn about all of NASA's missions at

That's all for this month. I'm Jane Houston Jones.


[1] Spica 角宿一

[2] Syrtis Major
It is a "dark spot" located in the boundary between the northern lowlands and southern highlands of Mars. For more information, visit at

[3] Perseids 英仙座流星雨

[4] Perseus 英仙座