Watch these feathered sharpshooters flip bubbles with giant anus

The glassy-winged lizard drinks a lot of water and therefore urinates a lot, excreting up to 300 times its body weight in urine every day. Instead of producing a constant flow of urine, shooters produce drops of urine in their anus and expel the drops from their bodies at incredible speeds, boasting a speed 10 times faster than a Lamborghini. Georgia Tech scientists have confirmed that the insect uses this new “superpropulsion” system to store energy, according to a new paper published in the journal Nature Communications.

A type of leafhopper, the sharp-winged glassy (Homalodisca vitripennis) is actually an agricultural pest, the scourge of California winemakers especially since the 1990s. It feeds on many types of plants (including grapes), piercing the plant’s xylem (which transports water from the roots to roots and leaves) and its needle-like mouth to suck the water. The insect consumes a lot of sap, and the amount of urine they produce consumes a lot of energy in turn, because of their small size and the sap’s taste and negative tension (it is actually sucked in). But fruit juice is about 95 percent water, so there isn’t enough nutrients to burn off all that peeing.

“If you’re just drinking lemonade for food, and that’s your whole diet, then you really don’t want to waste energy on any part of your metabolism,” said Georgia Tech’s Saad Bhamla, co-author of the New Scientist article. “It’s the same with this little organism.”

Bhamla and his colleagues used high-speed imaging to study the behavior of professional glass shooters in the laboratory: five insects, 22 drops of urine. and three different levels of urine. First, the styler rotates to release the bubbles of the peel. Once it reaches a certain size, in about 80 miles, the stylus rotates slightly, essentially loading the dot. Finally, the stylus makes one quick rotation to invert the drop of urine. A drop of water can move 40 percent faster than a stylus (ie in the highest regime). Get enough insects to do this at the same time and you will have “leafhopper water.”

The authors note that the physics of synthetic devices (like a pee droplet) is well known, requiring some time and some coordination between the player and the projection to increase the energy transfer and get the best energy. Specifically, “[s]uch counter-intuitive propulsion is only achieved in synthetic engines (such as water droplets) by carefully matching the frequency of the actuator’s vibration to the frequency of the device,” the authors wrote.

Bhamla compared how a sharpshooter uses his anal stylus to a diver jumping off a diving board. The authors’ models show that using this powerful device takes four to eight times less energy than just producing urine. As an added benefit, their urine secretions are far away making it less likely that the shooters will be detected by chemicals such as sewage.

Nor are sharpshooters the only type of insect that uses this excrement technique; nature has many “frass-shooters,” “butt-flickers,” and “turd-hurlers,” according to the authors. For example, skipper larvae have latches on their anal plates and can raise their blood pressure to expel solid pellets, while some noctuid species (moth family) expel pellets with their horn legs. But this is the first time superpropulsion has been seen in a living creature.

“At its core, superpropulsion provides a threshold to launch a synthetic device faster than the average speed of the actuator through temporal modulation and can be viewed as a one-shot resonance system,” the authors conclude. “For a body system dominated by the forces of friction, superpropulsion provides a technique by which this force of resistance can be used as a spring.” Potential applications include the efficient removal of water droplets from small electronic devices such as smartwatches, self-cleaning systems for wearable electronics, and decontamination systems for sunglasses and glasses.

DOI: Nature Communication, 2023. 10.1038/s41467-023-36376-5 (About DOIs).

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