You might not think much of blowflies. They grow up eating feces and spend their adult lives sniffing around for rotting carcasses to munch on. But when you consider that these insects can beat their wings up to 150x per second, all with muscles thinner than a strand of hair, you might develop a keener interest in these airborne nuggets of grossness. Thanks to this video released by the University of Oxford, you can now take a simulated peek inside the thorax of a blowfly and see how this miracle of biomechanics works.
The yellow and red muscles are responsible for driving the wings up and down, while the much smaller green and blue muscles help the fly steer. Dr. Simon Walker of the University of Oxford and first author of the paper in PLOS One Biology noted that these smaller muscles do this by actually changing the shape of the thorax itself. “It’s amazing how such tiny muscles have such a large effect,” said Walker.
To first make observations on how fly musculature worked, scientists used the Paul Sherrer Institute’s (PSI) Swiss Light Source. “The thoracic tissues block visible light, but can be penetrated by x-rays,” said Dr Rajmund Mokso of 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.” Spinning the flies around makes them try to turn, allowing scientists to observe the muscles involved when a fly changes direction during flight. It’s not often that an animal gets to ride a mini Gravitron in the name of science.
Here is a closer look at those steering muscles.