There is a small, 12-millimeter-long, benign-looking insect that is capable of quite a remarkable feat - projectile peeing, and a recent study discovered how important this accomplishment is for its survival.
This super-fast waste disposal explains the insect’s name, actually: glassy-winged sharpshooter (Homalodisca vitripennis). It can urinate at a speed of around 30 centimeters per second. It does so by flinging a bead of pee from its butt.
Saad Bhamla, a biomolecular engineer from the Georgia Institute of Technology in the US, wanted to take a closer look at the mechanics of this peeing.
"Little is known about the fluid dynamics of excretion, despite its impact on the morphology, energetics, and behavior of animals. We wanted to see if this tiny insect had come up with any clever engineering or physics innovations in order to pee this way," Saad Bhamla told media.
Using high-speed cameras and microscopes, Bhamla and his colleagues zoomed in on the catapult-style urination of the insect. They uncovered that its rear end can flip pee drops at great speed thanks to a stylus appendage, according to findings published in Nature Communications.
But there was more… As the team compared the speed of the stylus flick with the velocity of the actual pee droplets, they discovered that the drops travelled at speeds 1.4 times that of the stylus. Where was this superpropulsion coming from, they wondered... Further studies found that before shooting out the liquid waste, the stylus compressed the drops, storing energy so as to then send the pee flying.
Twitter screenshot.
© Photo : Twitter
"We realized that this insect had effectively evolved a spring and lever like a catapult and that it could use those tools to hurl droplets of pee repeatedly at high accelerations," Elio Challita, a biomolecular engineering student of Georgia Institute of Technology said.
A subsequent series of experiments, aided by computer modeling, revealed that this evolved manner of peeing helps the insects conserve the energy they absorb from nutrient-poor plant fluids that constitute their meal.