The Washington Post and other media outlets covered findings by Assistant Professor Saad Bhamla’s Lab showing how some sap-sucking insects use tiny catapult-like structures to fling droplets of pee faster than a cheetah can run.
Bhamla, a faculty member in the School of Chemical & Biomolecular Engineering, is an expert in “extreme biophysics” who is interested in the fastest movements in nature. He’s discovered that sharpshooter insects native to the Southeast United states and northeastern Mexico can fling urine at extreme accelerations – a finding that could be relevant to other challenging engineering problems, he says.
Bhamla explained to the Post that a tree infested with “pissing flies” can douse passersby with their waste, adding, “It’s crazy when you see it.”
Understanding how sharpshooters urinate enhances knowledge of the dynamics of speed, Bhamla notes. “First, we need to learn from nature how she does it, before we, as engineers, can build it,” he says.
A video on this phenomenon, titled “Insect Pee: Ultrafast fluidic ejection from sharpshooters,” won coverage in not only the Post, but also Science News and Canada’s CBC Radio after its submission by ChBE grad student Elio Chalita and undergrad Soham Sinha of the Bhamla lab to the APS Division of Fluid Dynamics’ conference Gallery of Fluid Motion. Science has also interviewed Bhamla for a forthcoming article on this research.
The researchers took high-speed video (thousands of frames per second) of the glassy-winged sharpshooter and blue-green sharpshooter species as they fed on plant tissue and flung their urine. The videos reveal that drops are catapulted off a tiny stylus on the insects’ rear after they collect.
With tiny hairs enhancing its catapult strength, the stylus flings the urine with a maximum acceleration 20 times that of Earth’s gravity and about 20 times faster than a cheetah runs, according to the study.
Bhamla told the Science News he doesn’t know why the insects fling their pee, but that the practice could help them evade predators that might be attracted to the fluid.
He explains in the Post article that this research points to “new ways of moving fast, other than just burning fuel.”
“As engineers, we should always turn to nature, because nature has had millions of years to evolve,” he says. “It’s an interesting way to think about how an insect might move really fast without using combustion. It’s nondestructive.”