Flies and Flight
The next time a fly or mosquito goes buzzing by your head and you risk throwing out your back again or swatting great grandma’s ancient antique vase off the counter and smashing it into a thousand and one pieces, consider this. Most flies’ wings flap over 200Hz or 200 cycles per second. A fruit fly beats its wings faster than neurons can fire. In addition to speed their ability to change directions, stop on a dime, hoover and land upside down is not only mind boggling but fun to watch.
Recently published research investigates how flies pull their speed and high flying antics. For some time researchers have known that all flies have a “gearbox” but had no idea where it was. Finally, the location of phantom gearbox has been found. This discovery is important not just from a biological sense but also because engineers often turn to insects for technical inspiration for biomimetic (synthetic methods that mimic biochemical processes) robots, drones, and other machines.
The question researchers needed to answer was how do wings and halteres (drumstick-like organs that function as gyroscopes to help flies orient themselves in flight) maintain precise coordination at such rapid frequencies? The researchers put forth two hypotheses. One possible explanation was that the wings and halters, although driven by independent sets of muscles, were mechanically coupled. A second explanation was that sensory feedback influences wing motor neurons.
To pinpoint where the mechanical coupling or “gear box” was controlled, researchers sliced through various parts of flies’ thoraxes, and filmed how it affected flight. When the researchers cut the sub-epimeral ridge (a bump on the lower side of a fly thorax), the fly’s transmission fell apart.