Are sharpshooter insects the ultimate pee propellors? New research has established that these small insects can fling huge volumes of urine a day using droplet superpropulsion. Their watery waste bullets spray with such vigor that it forms “leafhopper rain” as part of an incredible mechanism that conserves energy.
Getting enough water is an important part of staying alive, but as anyone who’s ever knocked back a Big Gulp before starting a long car journey can attest to, getting too much results in many a trip to the toilet. But what if you didn’t have to travel to the basin? What if, say, you could fling tiny droplets off your person so you stay squeaky clean with minimum effort?
As new research has uncovered, it seems this is precisely the approach adopted by millimeter-scale glassy wing sharpshooter insects from the Cicadellidae family, also known as leafhoppers. Sharpshooters have an unfavorable sap-sucking diet that’s 95 percent water and nutrient-poor, meaning they produce an above-average volume of urine per day.
Curiously, rather than ejecting that urine as a stream like many other animals and insects, they’ve been observed to pew-pew their pee-pee in the form of tiny droplets that fly vast distances to form puddles of urine that are a long way from the bug itself. This spray of droplets is known as leafhopper rain, and when these tiny insects move around in their millions it can feel like actual rain to any unsuspecting passing humans.
Sharpshooters have evolved to use superpropulsion as an excretion strategy by tuning what the researchers named a “butt flicker” to the frequency of their urine output so that it flings it at 40G forces in the form of tiny drops instead of a stream. Superpropulsion is defined as something moving faster than the thing that propelled it, and in the case of sharpshooters’ pee, it moves at 150 to 200 percent the speed of the butt flicker.
Looking at the business end of these insects under a microscope revealed the butt flicker is kitted out with structures not dissimilar to a catapult, which is how they achieve such remarkable propulsion for their tiny pee droplets.
Using models, computational fluid dynamics and biophysical experiments, they were able to establish that getting rid of urine in this way is actually less expensive, energetically speaking, than if the insects were to form jets. This is because when working with such tiny balls of water, the butt flicker gets an extra kick from the water’s surface tension as it squishes.
Creating such an elaborate way of urinating might seem over the top, but these insects pee 300 times the weight of their body daily, which is a staggering amount of pee when you consider that humans typically excrete just 2.5 percent of their bodyweight in urine daily. If you’re going to be peeing all day on a low-calorie diet, you’re going to need to find the most energy-efficient way to do it.
Behold, the butt flicker. Image credit: Bhamla Lab, Georgia Tech
Beyond being a remarkable introduction to the butt flicker, establishing the method behind the madness that is sharpshooter excretion not only teaches us about their evolutionary biology, but could also inform new kinds of energy-conserving soft robotics. That’s a lot to gain from a millimeter-sized sharpshooter.
“I love bugs, I think of them as nature’s tiny engineers because they come up with the most extraordinary and incredible solutions to life’s problems,” said study author Saad Bhamla in a Ted Talk about the research. “They’re so full of surprises and curiosities.”
The study was published in Nature Communications, and you can check out the Ted Talk here.
Source Link: Pinging Pee Droplets With Butt Flickers Helps Sharpshooter Insects Save Energy