Ever seen a water bottle the size of a beetle? What if, we told you that the bottle fills itself? Sounds like a miracle, doesn’t it? The Namib beetle belonging to the Stenocara genus is here to demonstrate this miracle. Found in the world’s oldest desert, the Namib desert, this beetle demonstrates an indigenous method of obtaining water from the arid surroundings. The desert records just 1.3 cm of rainfall a year which makes survival a herculean task. The Namib beetle however has quite easily adapted to the scarcity of water and devised its own tiny marvelous technique to stay alive!
The wing of the beetle has a super hydrophilic (water-loving) surface and is textured with super hydrophobic (water-
repelling) bumps. The hydrophilic surface of the wing helps the beetle trap moisture that is available in the arid air of the desert. By extending its wing surface, the beetle can collect water droplets that are up to 20 microns in diameter. The hydrophobic bumps repel these small droplets into narrow troughs that bring water droplets together. As the droplets grow bigger, they overcome the hydrophilic force and can be moved at will by the beetle. In order to consume the water droplets formed on its back, the beetle arches its back such that the drops roll down over the wing surface and then finally reach the beetle’s mouth. This type of mechanism allows the Namib beetle to extract the miniscule amounts of moisture available in the air, wait until condensation and then finally use these precious droplets to quench its thirst. In a way, the beetle carries its own “water bottle” giving it a choice to consume the stored water whenever and wherever it wants!
The combination of hydrophilic and hydrophobic surfaces efficiently used by the Namib Beetle has been an inspiration for scientist all over the world. Scientists are looking for nanomaterials that attract and store water. Research so far has helped, the company, NDB Nano, in creating a water bottle that has has self-filling capabilities of almost 3 litres every hour.