Johns Hopkins University / YouTube

Information on the mechanics of a painted lady butterfly's flight patterns gleaned from high-speed video may be used to construct better designs for military drones.

High-speed video cameras are allowing university researchers to document how butterflies gracefully flutter through the air. The U.S. military funded findings may lead to more agile insect-sized drones sent to spy on enemies.

A key finding is that butterflies appear to use their bodies and wings to twist and turn in the air in a way similar to how ice skaters use their arms to control the speed of their spins, explains Johns Hopkins University undergraduate Tiras Lin, who is working on the high-speed video research.

"Ice skaters who want to spin faster bring their arms in close to their bodies and extend their arms out when they want to slow down," he explains in the video news release below.

"These positions change the spatial distribution of a skater's mass and modify their moment of inertia; this in turn affects the rotation of the skater's body. An insect may be able to do the same thing."

To capture the images of butterflies in flight, Lin used video cameras that record 3,000 one-megapixel images per second. To put that in perspective, a standard video camera shoots 24, 30 or 60 frames per second. "Butterflies flap their wings about 25 times per second," Lin notes.

Most of his analysis zeroed in on 1/5th of a second of flight, or about 600 frames.

Lin recently presented his findings at a meeting of the American Physical Society's Division of Fluid Dynamics. While they haven't yet been adopted by next-generation drones, he said they ought to be. To see how else drones could get buggier in the future, check out the stories below.

More stories on insect-inspired drone technology:

• Biofuel cells may turn cockroaches into cyborgs
• Military developing robot-insect cyborgs
• On wings of technology: Humming bird drones
• Ant-like robots poised to invade the marketplace

Julie Larsen Maher

This cockroach may look harmless, but researchers are working on biofuel cell technology that can turn these bugs into spies.

The sugars in a cockroach's belly have been harnessed by a fuel cell and converted into electricity, a big step toward turning insects into cyborgs, scientists are reporting.

Once miniaturized to the point that the fuel cells are non-invasive to the cockroaches, they can be implanted to power sensors or recording devices, for example.

A rechargeable battery inserted along with the so-called biofuel cell would store the trickle of energy it generates, explained Daniel Scherson, a chemist at Case Western Reserve University in Cleveland.

"If you want to be futuristic, one may use the energy stored to try to control the neurological system of the cockroach and then you might be able to (control) the cockroach (with) a joystick," he told me.

Yes, in the future, that nasty cockroach scurrying across the kitchen floor might actually be a spy set loose by a nosy neighbor, or the CIA.

Sugar fuel
The power supply for this fuel cell is food the cockroaches eat, avoiding the need for devices that harness electricity from movement, such as shoes that turn mechanical energy into electricity.

The fuel cell devised by Scherson's team uses a cascade of reactions by enzymes to convert energy stored as sugars into electricity.

The first enzyme breaks down the sugar trehalose, which cockroaches constantly produce from their food, into two simpler sugars. 

A second enzyme oxidizes the simple sugars, releasing electrons that "can then be funneled together to electrodes where they are captured and delivered to oxygen," Scherson explained.

The team first tested the system on trehalose solutions, then inserted prototype electrodes into the belly of a female cockroach. It worked.

The biofuel cell produced a trickle of electricity — 0.2 volts. Full details on the system are published online in the Journal of the American Chemical Society.

Intermittent tasks
Since the researchers don't want to load down a bug with a heavy fuel cell and impair its ability to move, they envision storing the energy up in a battery, then using that energy to perform tasks such as power sensors.

One potential application is to equip social insects such as bees or ants with sensors tuned to detect a dangerous chemical and send them out to the environment. 

Periodically, the sensor would turn on and broadcast its finding, shutting down between broadcasts to allow the battery time to recharge.

Operating at 0.2 volts is enough power to send a message a few inches, according to Scherson, far enough that a message could be sent down a line of ants spying on a top-secret meeting in a park.

To get there, the researchers need to shrink their fuel cells so they can be fully implanted, find long-lasting materials to make them with so they don't breakdown inside the bugs' bodies, and build the signal transmitters.

All of this is in the realm of possibility, noted Scherson.

"People do wonderful things with circuitry."

More on cyborg insects:

• Military developing robot-insect cyborgs
• Tiny cyborg beetles could recharge just by flying
• Ant-like robots poised to invade the marketplace
• Robotic insects take flight on wings made using printers