Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antennae Help Flies "Cruise" In Gusty Winds

11.04.2014

Caltech researchers uncover a mechanism for how fruit flies regulate their flight speed, using both vision and wind-sensing information from their antennae.

Due to its well-studied genome and small size, the humble fruit fly has been used as a model to study hundreds of human health issues ranging from Alzheimer's to obesity. However, Michael Dickinson, Esther M. and Abe M. Zarem Professor of Bioengineering at Caltech, is more interested in the flies themselves—and how such tiny insects are capable of something we humans can only dream of: autonomous flight. In a report on a recent study that combined bursts of air, digital video cameras, and a variety of software and sensors, Dickinson and his team explain a mechanism for the insect's "cruise control" in flight—revealing a relationship between a fly's vision and its wind-sensing antennae.


A tracing of the flies' flight trajectories as they explore in a wind tunnel, as seen from above. Each observation by the cameras is scaled according to flight speed, as if the animal was dribbling paint as it was flying; the longer the residence time, the larger the dot. Each trajectory is shown in a different color. The stars indicate when the flies were subjected to a brief gust of wind. These experiments revealed how the wind-sensing antennae stabilize the fly's visual flight controller.Credit: Sawyer Fuller/Caltech

The results were recently published in an early online edition of the Proceedings of the National Academy of Sciences.

Inspired by a previous experiment from the 1980s, Dickinson's former graduate student Sawyer Fuller (PhD '11) wanted to learn more about how fruit flies maintain their speed in flight. "In the old study, the researchers simulated natural wind for flies in a wind tunnel and found that flies maintain the same groundspeed—even in a steady wind," Fuller says.

Because the previous experiment had only examined the flies' cruise control in gentle steady winds, Fuller decided to test the limits of the insect's abilities by delivering powerful blasts of air from an air piston in a wind tunnel. The brief gusts—which reached about half a meter per second and moved through the tunnel at the speed of sound—were meant to probe how the fly copes if the wind is rapidly changing.

The flies' response to this dynamic stimulus was then tracked automatically by a set of five digital video cameras that recorded the fly's position from five different perspectives. A host of computers then combined information from the cameras and instantly determined the fly's trajectory and acceleration.

To their surprise, the Caltech team found that the flies in their experiments, unlike those in the previous studies, accelerated when the wind was pushing them from behind and decelerated when flying into a headwind. In both cases the flies eventually recovered to maintain their original groundspeed, but the initial response was puzzling, Fuller says. "This response was basically the opposite of what the fly would need to do to maintain a consistent groundspeed in the wind," he says.

In the past, researchers assumed that flies—like humans and most other animals—used their vision to measure their speed in wind, accelerating and decelerating their flight based on the groundspeed their vision detected. But Fuller and his colleagues were also curious about the in-flight role of the fly's wind-sensing organs: the antennae.

Using the fly's initial response to strong wind gusts as a marker, the researchers tested the response of each sensory mode individually. To investigate the role of wind sensation on the fly's cruise control, they delivered strong gusts of wind to normal flies, as well as flies whose antennae had been removed. The flies without antenna still increased their speed in the same direction as the wind gust, but they only accelerated about half as much as the flies whose antennae were still intact. In addition, the flies without antennae were unable to maintain a constant speed, dramatically alternating between acceleration and deceleration. Together, these results suggested that the antennae were indeed providing wind information that was important for speed regulation.

In order to test the response of the eyes separately from that of the antennae, Fuller and his colleagues projected an animation on the walls of the fly-tracking arena that would trick the eyes into thinking there was no speed increase, even though the antenna could feel the increased windspeed. When the researchers delivered strong headwinds to flies in this environment, the flies decelerated and were unable to recover to their original speed.

"We know that vision is important for flying insects, and we know that flies have one of the fastest visual systems on the planet," Dickinson says, "But this response showed us that as fast as their vision is, if they're flying too fast or the wind is blowing them around too quickly, their visual system reaches its limit and the world starts getting blurry." That is when the antennae kick in, he says.

The results suggest that the antennae are responsible for quickly sensing changes in windspeed—and therefore are responsible for the fly's initial deceleration in a headwind. The information received from the fly's eyes—which is processed much more slowly than information from the wind sensors on the antenna—is responsible for helping the fly regain its cruising speed.

"Sawyer's study showed that the fly can take another sensor—this little tiny antenna, which doesn't require nearly the amount of processing area within the brain as the eyes—and the fly is able to use that information to compensate for the fact that the information coming out of the eyes is a bit delayed," Dickinson says. "It's kind of a neat trick, using a cheap little sensor to compensate for the limitations of a big, heavy, expensive sensor."

Beyond learning more about the fly's wind-sensing capabilities, Fuller says that this information will also help engineers design small flying robots—creating a sort of man-made fly. "Tiny flying robots will take a lot of inspiration from flies. Like flies, they will probably have to rely heavily on vision to regulate groundspeed," he says.

"A challenge here is that vision typically takes a lot of computation to get right, just like in flies, but it's impossible to carry a powerful processor to do that quickly on a tiny robot. So they'll instead carry tiny cameras and do the visual processing on a tiny processor, but it will just take longer. Our results suggest that little flying vehicles would also do well to have fast wind sensors to compensate for this delay."

The work was published in a study titled "Flying Drosophila stabilize their vision-based velocity controller by sensing wind with their antennae." Other coauthors include former Caltech senior postdoc Andrew D. Straw, Martin Y. Peek (BS '06), and Richard Murray, Thomas E. and Doris Everhart Professor of Control and Dynamical Systems and Bioengineering at Caltech, who coadvised Fuller's graduate work. The study was supported by the Institute for Collaborative Biotechnologies through funding from the U.S. Army Research Office and by a National Science Foundation Graduate Fellowship.

Written by Jessica Stoller-Conrad

Contact: 

Deborah Williams-Hedges

(626) 395-3227

debwms@caltech.edu

Deborah Williams-Hedges | Eurek Alert!
Further information:
http://www.caltech.edu

Further reports about: ALZHEIMER Dickinson Technology antennae cameras eyes flies fly fly's trajectory insects role small tiny

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>