The amazing fly
Flies are some of the greatest fliers in the insect kingdom. They can fly in any direction, even backward, and can hover as well making them extremely difficult to catch. Their wings beat at over 200 cycles per second and fruit flies can beat their wings once every four milliseconds. That is faster than neurons can fire. Research investigating their amazing flying skills has recently been released. While it has been known for a long time that flies have a “gear change box” that helps them speed up their wing speed new research has identified the clutch and transmission that helps them do their aerial acrobatics.
How do flies fly?
Flies only have two functional wings while the other pair are organs called halteres. These halters act as gyroscopes to orient the flies in flight. These organs flap in opposition to the functional wings and measure torque and angular momentum around the body.
Most insects with two pairs of wings have both sets flapping in concert to give them a larger surface area during flight. Flies don’t do this, and it takes a level of sophistication that is almost unparalleled. When scientists dissected flies to figure this out and moved the left wing with a pair of tweezers. When they did this the other wing also moved as did the halteres. The scientists found that when they cut the sub-epimeral ridge lengthwise the fly’s wings and halteres stopped moving in concert and their “transmission” fell apart.
This mechanical coupling explains how flies manage this coordination but how do they do a sharp turn or flap just one wing at a time? Scientists have proposed that flies “gear change box” has four different gears. One neutral and three speeds. By using these different gears flies can change the power of each wing stroke and even put one wing in neutral while the other continues to flap.
Deora, et al. 2015. Biomechanical basis of wing and haltere coordination in flies. PNAS doi: 10.1073/pnas.1412279112