3-D video from inside flying insects

March 25, 2014

The flight muscles moving inside flies have been filmed for the first time using a new 3D X-ray scanning technique.

3D movies of the muscles were created by a team from Oxford University, Imperial College London, and the Paul Scherrer Institute (PSI), using the PSI's Swiss Light Source, a powerful X-ray source. The movies offer a glimpse into the inner workings of one of nature's most complex mechanisms, the blowfly's flight motor, and could inspire new designs of and other micromechanisms.

A report of this research, including the 3D movies, is published in this week's PLOS Biology.

In the time that it takes a human to blink, a blowfly [Calliphora vicina] can beat its wings 50 times, controlling each wingbeat using numerous tiny steering muscles – some as thin as a human hair. The membranous wings contain no muscles, so all of the flight muscles are hidden out of sight within the thorax.

'The thoracic tissues block visible light, but can be penetrated by X-rays,' said Dr Rajmund Mokso from the PSI. 'By spinning the flies around in the dedicated fast-imaging experimental setup at the Swiss Light Source, we recorded radiographs at such a high speed that the flight muscles could be viewed from multiple angles at all phases of the wingbeat. We combined these images into 3D visualizations of the flight muscles as they oscillated back and forth 150 times per second.'

The flies responded to being spun around by trying to turn in the opposite direction, allowing the scientists to record the asymmetric muscle movements associated with turning flight.

This video is not supported by your browser at this time.
This video shows the insect thorax reconstructed from tomograms and highlights the external movements of the thorax and the location of the indirect power and steering muscles. This is Movie S1 from the article. Credit: doi:10.1371/journal.pbio.1001823

'The key question is how the fly's tiny steering muscles, which make up less than 3% of its total flight muscle mass, influence the output of the much larger muscles that power its flight,' said Professor Graham Taylor of Oxford University's Department of Zoology who led the research in Oxford. 'We found that blowflies have evolved a mechanism rather like the differential in a car; whilst the power delivered to the fly's wings on each side remains the same, the fly effectively 'brakes' on one side by diverting excess power into a steering muscle specialized to absorb mechanical energy.'

This video is not supported by your browser at this time.
The muscles are shown for the high-amplitude (left) and low-amplitude (right) wings through ten stages of the wingbeat, starting at the beginning of the downstroke. The steering muscles are viewed from the inside of the thorax looking out toward the wing hinge, and other parts of the thorax have been removed for clarity. The view of the low-amplitude (right) wing muscles has been mirrored about the sagittal plane of the insect for ease of comparison. The basalare sclerite is not visible directly in the reconstruction, but its position can be inferred by the intersection of the b1 and b3 steering muscles. This is Movie S2 from the article. Credit: doi:10.1371/journal.pbio.1001823

This video is not supported by your browser at this time.
Differences in the deformations of the thorax and the movement of the basalare sclerite are shown for the high-amplitude (left) and low-amplitude (right) wings through ten stages of the wingbeat, starting at the beginning of the downstroke. The low-amplitude (right) view has been mirrored about the sagittal plane of the insect for ease of comparison. This is Movie S3 from the article. Credit: doi:10.1371/journal.pbio.1001823
Professor Holger Krapp from Imperial College London's Department of Bioengineering said: 'We are excited because for the first time, we can visualise how the power and steering muscles in the fly's thorax work to enable stunningly aerobatic flight manoeuvres unmatched by any manmade device. Our study opens up the opportunity to uncover how the fly controls its sophisticated flight engine using the signals from different sensors and a brain no larger than the size of a pin head.'

Professor Taylor said: 'We hope that our new understanding of this clever design, which produces large, complex 3D movements using actuators that only generate small, simple one-dimensional motions, will inspire the development of new micro air vehicles and other micromechanical devices.'

Dr Simon Walker from Oxford University, joint first author of the study with Daniel Schwyn, said: 'The fly's wing hinge is probably the most complex joint in nature, and is the product of more than 300 million years of evolutionary refinement. The result is a mechanism that differs dramatically from conventional manmade designs; built to bend and flex rather than to run like clockwork.'

Explore further: Birds 'flap run' instead if flying over obstacles to save energy

More information: Walker SM, Schwyn DA, Mokso R, Wicklein M, Müller T. et al. (2014) In Vivo Time-Resolved Microtomography Reveals the Mechanics of the Blowfly Flight Motor. PLoS Biol 12(3): e1001823. DOI: 10.1371/journal.pbio.1001823

Related Stories

A new, flying jellyfish-like machine (w/ Video)

November 24, 2013

Up, up in the sky: It's a bird! It's a plane! It's a... jellyfish? That's what researchers have built—a small vehicle whose flying motion resembles the movements of those boneless, pulsating, water-dwelling creatures.

Bats inspire 'micro air vehicle' designs

February 18, 2014

By exploring how creatures in nature are able to fly by flapping their wings, Virginia Tech researchers hope to apply that knowledge toward designing small flying vehicles known as "micro air vehicles" with flapping wings.

Recommended for you

Scientists overcome key CRISPR-Cas9 genome editing hurdle

December 1, 2015

Researchers at the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT have engineered changes to the revolutionary CRISPR-Cas9 genome editing system that significantly cut down on "off-target" ...

Study finds 'rudimentary' empathy in macaques

December 1, 2015

(Phys.org)—A pair of researchers with Centre National de la Recherche Scientifique and Université Lyon, in France has conducted a study that has shown that macaques have at least some degree of empathy towards their fellow ...

Which came first—the sponge or the comb jelly?

December 1, 2015

Bristol study reaffirms classical view of early animal evolution. Whether sponges or comb jellies (also known as sea gooseberries) represent the oldest extant animal phylum is of crucial importance to our understanding of ...

Trap-jaw ants exhibit previously unseen jumping behavior

December 1, 2015

A species of trap-jaw ant has been found to exhibit a previously unseen jumping behavior, using its legs rather than its powerful jaws. The discovery makes this species, Odontomachus rixosus, the only species of ant that ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.