Scientists have long assumed that springtails — tiny, insect-like creatures found all over the world — fling themselves into the air at random to flee from predators and other dangers. To the naked eye, their characteristic leaping motion appears uncontrolled, flailing, and aimless.
But when captured with sophisticated cameras that slow their movements, springtails actually look like nimble little gymnasts, perfectly performing gravity-defying somersaults that can count up to 500 times a second — and they land on their feet most of the time.
These results, published in the journal on Monday Proceedings of the National Academy of Sciences, challenge the long-held belief that springtails have no control over their explosive leaps. Inspired by this not-so-random jumping, scientists also built springtail-like jumping robots.
Victor Ortega-Jiménez, a biomechanist at the University of Maine and the study’s lead author, began thinking critically about springtails during the coronavirus pandemic, which led to him spending less time in the lab and more time in nature.
Springtails caught his attention while exploring rivers in Georgia with his family. Watching the small hexapods jump, Ortega-Jiménez got the distinct impression that, contrary to popular scientific belief, 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, recording up to 10,000 frames per second, provided a clear view of what the acrobatic springtails were doing during takeoff, mid-air turns and landing. They jumped in certain directions, straightened up in the air, and adjusted their body positions to land back on their feet.
Their twist in the air is similar to a cat’s ability to orient itself during a fall, leading to the saying that “cats always land on their feet”. But springtails rear up much faster than cats and other animals, taking less than 20 milliseconds to adjust their bodies for landing, the scientists find.
This special ability comes from the springtails’ unique body parts, as the footage shows. They use a long, flexible, tail-like appendage called a furcula to smack the surface of the water and throw them into the air. As they fly, they bend into a “U” shape to slow their rotation. And an abdominal tube called a collophore helps them land. This tube captures a drop of water on launch, which stabilizes the springtail in the air and acts as an anchor for perfect water landings, even in a lab wind tunnel.
“They jumped with a parachute and landed on their feet,” says Ortega-Jiménez New York Times“Oliver Whang.
The tiny creatures likely evolved their precise jumping abilities for survival: landing on their feet allows them to recover quickly and jump again if necessary to avoid danger. In the lab, springtails landed on their feet about 85 percent of the time, according to the study.
Researchers say this discovery could lead to advances in robotics. They tried to mimic the movements of springtails by building a tiny robot that landed upright about 75 percent of the time. Further research inspired by springtail biomechanics could help improve robot accuracy even further.
“Controlling their orientation in the air for landing and jumping has been a major challenge for jumping robots, especially at small scales,” says study co-author Je-Sung Koh, a mechanical engineer at Ajou University, in a statement . “Findings from this research could inspire insect-scale jumping robots capable of safe landing and expand robotic capabilities in new terrains such as the open water surfaces in our planet’s lakes and oceans.”
Many people overlook springtails — which makes sense considering most of the 9,000 known species are about the size of a grain of sand. Also, springtails do not bite or sting people. They are harmless acrobatic wonders.
But this new research suggests they deserve a second look. Not only are they interesting to look at 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 not involved in the study Science news“Susanne Milius.