March 3, 2023, 7:48 PM
All animals, including insects, need to get rid of their waste. After Saad Bhamla, a biomechanics specialist at Georgia Tech, saw an insect urinating in his garden, he was curious as to what mechanisms it used to relieve himself on him. He watched as the insect formed an almost perfect round blob on its tail that seemed to catapult out, a pattern that repeated itself for hours.
These small leafhoppers, about 12 millimeters in length, have a built-in mechanism to launch their urine droplets at a speed of 40 G, according to research published in the journal Nature Communications. To this we should add that they urinate up to 300 times the equivalent of their body weight per day.
“Blinking Rear” and Superdrive
Georgia Tech scientists studied these insects using high-speed video and microscopy to find out exactly what was going on. The insect is endowed with an anal appendage that researchers call a “blinking butt,” which retracts and then releases a droplet of urine at high speed.
“We realized that this insect had evolved a spring and a lever like a catapult and that it could use these tools to launch drops of urine repeatedly at high speeds,” explains Elio Challita, co-author of the study.
When the team measured the airspeed of these anal ejections, they found that they were traveling 1.4 times faster than butt flashing triggered them. This suggests that the bugs make use of a physical principle called superdrive, never before seen in animal species.
A very basic example of superdrive might be what happens when you shoot off a trampoline after rebounding.
It may seem like an elaborate way to urinate, but the researchers found that it’s the most energy-efficient method for their lifestyle, since they only eat plant sap, which has basically zero nutrients, meaning they they have to drink – and urinate – practically non-stop.
“What these insects have to deal with is like us trying to shake off a beach ball-sized bubble of maple syrup,” says Miriam Ashley-Ross, director of programs at the National Science Foundation. “The effective method that these tiny insects have developed to solve the problem may lead to bio-inspired solutions to quickly remove solvents or shake water off complex surfaces,” she says.