Do insects flap at their resonant frequency?

Centimeter-scale flapping flight is an extremely power-intensive way to get around, because it requires powerful, muscle-driven movement at high frequencies. The fastest insects flap their wings at nearly 1000 times per second! Since the discovery of elasticity in the insect thorax, it has been thought that insects flap at their resonant frequency to fly efficiently, but at the expense of ability to rapidly change their wingbeat frequency. This is the same tradeoff you experience on a trampoline or swing set – changing frequency is hard at resonance, but potentially important for flight control.

In this project, we are interested in measuring the resonant frequencies of insects to determine whether they flap at resonance to maximize efficiency or flap off resonance sacrificing efficiency for control. We do this by measuring the stiffness of insect thoraxes, strains undergone by the flight muscles, and developing ‘spring-wing’ models of resonant aerodynamics. Putting these pieces together, we can better understand how insect flight has evolved, and how we can build insect-inspired robots that balance efficiency and control.