Scientists have long assumed that springtails—teeny-tiny insect-like creatures found all over the world—fling themselves into the air at random to flee predators and other dangers. To the naked eye, their signature jumping motion appears uncontrolled, flailing and aimless.
But when captured with sophisticated cameras that slow down their movements, springtails actually look like skilled little gymnasts, perfectly executing gravity-defying flips that can number up to 500 per second—and they land on their feet most of the time.
These findings, published Monday in the journal Proceedings of the National Academy of Sciences, challenge the long-held belief that springtails have no control over their explosive bounces. Inspired by this not-so-random jumping, the scientists also built springtail-like leaping robots.
Victor Ortega-Jiménez, a biomechanist at the University of Maine and the study’s lead author, started thinking critically about springtails during the coronavirus pandemic, which led him to spend less time in the laboratory and more time out in nature.
Springtails captured his attention while he was exploring rivers in Georgia with his family. While watching the little hexapods leap, Ortega-Jiménez got the distinct impression that, contrary to popular scientific opinion, they knew exactly what they were doing in the air.
He brought his observations back to the lab, where he and several colleagues used high-speed cameras to film a semiaquatic species known as Isotomurus retardatus.
The cameras, which captured up to 10,000 frames per second, offered a clear view of what the acrobatic springtails were doing during takeoff, midair spinning and landing. They jumped in specific directions, righted themselves in the air and adjusted their body positioning to land on their feet again.
Their midair twisting is similar to a cat’s ability to orient itself during a fall, which gave rise to the adage that “cats always land on their feet.” But springtails right themselves much more quickly than cats and other animals do, taking less than 20 milliseconds to orient their bodies for landing, the scientists find.
This special ability comes from springtails’ unique body parts, the footage reveals. They use a long, hinged, tail-like appendage called a furcula to smack the water’s surface, launching them into the air. As they fly, they bend into a “U” shape to slow their spinning. And an abdominal tube called a collophore helps them stick the landing. This tube picks up a drop of water at takeoff, which stabilizes the springtail while in the air and acts as an anchor to perfect water landings, even inside a laboratory wind tunnel.
“They were skydiving, and they were landing on their feet,” says Ortega-Jiménez to the New York Times’ Oliver Whang.
The infinitesimal creatures likely evolved their accurate jumping abilities for survival: Landing on their feet allows them to recover quickly and, if necessary, jump again to dodge danger. In the laboratory, springtails landed on their feet roughly 85 percent of the time, per the study.
Researchers say this discovery could lead to advances in robotics. They tried to mimic the springtails’ movements by building a tiny robot, which landed upright about 75 percent of the time. Further research, inspired by the biomechanics of springtails, could help improve robots’ accuracy even more.
“It has been a major challenge for jumping robots, specifically at small scales, to control their orientation in the air for landing and jumping,” says study co-author Je-sung Koh, a mechanical engineer at Ajou University in South Korea, in a statement. “The finding in this research could inspire insect-scale jumping robots that are able to land safely and expand the capability of robots in new terrains, such as the open-water surfaces in our planet's lakes and oceans.”
Many people overlook springtails—which makes sense, considering that most of the 9,000 known species are about the size of a grain of sand. What’s more, springtails don’t bite or sting humans. They are harmless acrobatic wonders.
But this new research suggests they deserve a second look. Not only are they interesting to watch and—some might say—cute, but “they are also among the most numerous and functionally important animals on our planet,” says Anton Potapov, a soil animal ecologist at the University of Göttingen in Germany who was not involved in the study, to Science News’ Susan Milius.