Springtails stick the landing as the world’s tiniest acrobats
Reference: Ortega-Jimenez, V. M., Challita, E. J., Kim, B., Ko, H., Gwon, M., Koh, J. S., & Bhamla, M. S. (2022). Directional takeoff, aerial righting, and adhesion landing of semiaquatic springtails. Proceedings of the National Academy of Sciences, 119(46), e2211283119. https://doi.org/10.1073/pnas.2211283119
Featured Image Caption: Tiny springtails get their name from their mighty, forked tail that propels them to great heights (Image Source: “Springtail (Collembola)” by The NYSIPM Image Gallery is licensed under CC BY 2.0.).
If animals competed in the Olympics, many events would have clear winners – the fastest, strongest animals would likely go uncontested. However, there are sure to be some surprises in some categories. One might think that the victor of aerial acrobatics would go to a monkey that effortlessly swings from tree to tree or to the agile cat capable of landing on its feet time after time. Nonetheless, the true champion of aerial stunts is the springtail, as recently awarded by scientists.
The springtail gets its name from its unique tail-like feature that allows it to spring into the air at heights many times its body length. Like their close relatives – the insects – springtails have six legs. The nearly 8000 species of springtails live across the world in damp, semiaquatic environments. In households, they inhabit any place that remains consistently damp, such as garages, basements, and potted plants. These tiny animals (often less than 6 mm long) are nothing to fear, as they do not harm humans, animals, or plants. On the contrary, they are beneficial decomposers that turn decaying plant materials into nutrient-rich soil.
What makes springtail’s leaps so unique? Despite being entirely wingless, they can still soar with the help of aerodynamics. Their skillful springs have even inspired robotic designs. With the help of two unique structures, springtails can right themselves in midair and stick the landing almost every time – all within the blink of an eye.
Prepared for Take-Off
Springtails possess two body parts that are thought to help them complete their aerodynamic feats: the furcula and collophore. The furcula is a forked tail that rests in a position similar to a tail of a frightened dog – tucked under the abdomen. The collophore is a cylinder-shaped part hanging on the abdomen’s underside. Its scooped-out end holds a water droplet that is approximately 3% of its body weight. First and foremost, this water droplet anchors the individual to water or a solid surface.
Using videos, experiments, and models, researchers Victor Ortega-Jimenez and colleagues closely observed what role these structures play in controlling flight.
During take-off, the furcula controls the exit speed from the water’s surface. Like a mighty hinge, the furcula extends with enough force to thrust the tiny creature into the air. Springtails can also control the height and distance of the leap by changing their body orientation. A lowered back positions the furcula nearly parallel to the surface of the water, allowing jumps that go higher with less distance. Further, lower leaps are accomplished by raising the back at take-off.
Sticking the Landing
Arguably, the most remarkable stunt occurs in midair. With cat-like reflexes, springtails can right themselves midair to land in a favorable, upright position. Even more extraordinary is that they right themselves in just 20 milliseconds – the fastest ever recorded. How do they do it? They fold their furcula back to its original position and arch their back into a U-shape. This slows their rotational speed. The added weight from the water droplet held in the collophore then directs their feet toward the surface. Faster than you can blink, the springtail is ready to land on its feet.
At heights 16 times greater than their body length, springtails are posed for a successful feet-first landing. As the springtail approaches the surface, its water-filled collophore is the first to contact the water or solid surface to dampen the impact. When researchers experimentally removed the collophore, the springtails bounced upon impact. With the collophore’s help, 85% of all leaps landed successfully.
In addition to being a scientific wonder, these skilled jumps help springtails escape predators and threats, as well as help them move more quickly through space. Landing on one’s feet becomes extremely important when running from a threat. With hundreds of millions of years of fine-tuning their take-off and landing gear, springtail’s leaps are helping scientists to build more aerodynamic robots. As we depend on many aircrafts to land safely – like airplanes, drones, and spacecrafts – gaining controlled-landing insight from springtails could lead to the next big innovation. That is one small leap for springtails but one giant leap for scientific discovery.
Checkout the slow-motion videos at the bottom of the paper’s website: https://www.pnas.org/doi/suppl/10.1073/pnas.2211283119.