A robot walks on water thanks to evolution’s solution

Gliding effortlessly across rushing streams, tiny robots inspired by water-striding insects are redefining what mechanical creations can do on liquid surfaces. These "Rhagobots," modeled after Rhagovelia water striders, harness the same evolutionary adaptations that allow the insects to navigate water with remarkable agility.

The secret lies in fan-like appendages on the middle legs that automatically adjust to water movement. Biologist Victor Ortega-Jimenez spent five years studying how these appendages work, discovering they respond to surface tension rather than muscle power.

"Rhagovelia's fan serves as an inspiring template for developing self-morphing artificial propellers," Ortega-Jimenez noted in his Science publication.

These remarkable fans open and close ten times faster than a human blink, expanding instantly upon water contact and changing shape with the flow. The structures generate tremendous propulsion while remaining versatile enough to collapse when out of water.

Through electron microscopy, researchers discovered these fans aren't cylindrical as previously thought, but complex structures made of flat barbs with barbules—a crucial insight that made the water-walking robots possible.