June 24, 2024

These Insects’ “Real” Evolutionary Trick Could Revolutionize Your Kitchen

Nature is inspiring scientists all the time. Some ideas are still being researched, such as super warm beaver inspired wet suit. But others are already part of human life, like velcro (based on burdock burrs) and the Japanese bullet train (based on the long, narrow beak of the kingfisher).

Cicadas inspired my team recent research into self-cleaning surfaces.

Keeping your car window panes spotless can feel like a never-ending battle against the forces of dirt and dust. But insects like cicadas have a great trick up their sleeve that keeps their wings spotless without the insects doing it. And it could hold the key to saving us the trouble of constant cleaning.

My team’s study investigated the mechanism behind this self-cleaning process.

Thanks to the peculiar texture of cicada wings, the morning dew condenses on them and gradually grows into small water droplets. These droplets dislodge dust particles and microorganisms as they collide with each other or roll down the insect’s wings.

Cicadas are not the only insects that have developed self-cleaning bodies. enough butterflies have wings that can clean themselves. Like other creatures geckos and leaves of certain plants, for example lotus and rice, also use droplets to keep themselves free from dust, as cicadas do. These moving droplets also help remove bacteria, which lowers the risk of infection.

Water ‘beads’ on a lotus leaf.


If liquid is spilled on most surfaces (think an overturned coffee mug), it will simply spread over the area and stay there.

But dew droplets behave differently on cicada wings because of something engineers call “super-hydrophobicity,” or extreme water repellency. The surface of Cicada wings has a complex arrangement thousands of tiny wax-coated cones. Water droplets on the wing take a bead-like shape because they want to minimize contact with the surface of the wing. This is due to the wax that repels water and the conical tips, which prevent spherical water droplets from entering the wing membrane.

This would look just like a fully blown balloon placed over a bed of nails. It will not pop because the pressure is distributed on the nails. In the case of droplets, the wax-coated cones facilitate the effortless movement of droplets on cicada wings.

Artist’s rendering of a water droplet (cluster of blue molecules) jumping off a cicada wing carrying a contaminant (red particle).

S. Perumanath, Author provided (no reuse)

Jumping and rolling water droplets

Previous studies have shown gravity more droplets roll down the waxy wings of cicadaspicking up many contaminants along their journey.

However, until now, how smaller droplets, too small to be pulled by gravity, picked up dirt was not possible. We discovered that small droplets will, over time, merge with their neighbors.

The merged droplet jumps off the surface instead of rolling off. During the jump, the droplet will take on a balloon-like shape in the hot air about to lift off the ground. Our study showed that the balloon shape in this warm air is crucial to enable droplets to carry dirt from the surface.

Jumping water droplets

Water droplets go towards each other, merge, drag the dust particle below, and jump out by carrying it from the surface. A hot air balloon configuration is seen in the third image.

S. Perumanath

It turns out that the surface tension of the liquid droplet picks up the dirt and the droplet balloons into the hot air. Surface tension is the tendency of droplets exposed to air to maintain a spherical shape. When a droplet forms the balloon shape in the warm air with dirt below, it will try to reform as a sphere. In the process, it inadvertently pulls the dirt from the surface.

We also noticed that water droplets cannot remove all contaminants in this way. For example, on cicada wings, water droplets may be able to remove tiny particles of sand but not those made of soot.

We also found that regardless of whether droplets jump or roll, the mechanism for releasing contaminants from a surface remains the same. As a droplet rolls more dirt down, its surface will be distorted. The droplet will try to maintain its natural spherical shape, which will attract the dirt from the surface, as in compound droplets.

Natural engineering

In the future, engineers can incorporate what we learned about cicada wings into product designs, and we may no longer need to splash water and clean our window panes and other surfaces because they will clean themselves.

Imagine skyscraper windows, solar panels, and surveillance camera lenses that can clean themselves. A super hydrophobic coating can also help prevent the formation of frost on various surfaces in the winter – like your car’s windshield.

This will add nicely to the list of upcoming upgrades to our existing infrastructure alongside it efficient solar panels inspired by plant leaf structure and termite-mound buildings with more efficient ventilation in cities around the world.

Even in the most urban places, we are surrounded by nature.

This article was originally published The conversation by Sreehari Perumanath at the University of Warwick. Read the base here.

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