''Stenocara gracilipes'' is a species of beetle that is native to the Namib Desert in southern Africa. This is one of the most arid areas of the world, receiving only of rain per year. The beetle is able to survive by collecting water on its bumpy back surface from early morning fogs. To drink water, the ''S. gracilipes'' stands on a small ridge of sand using its long, spindly legs. Facing into the breeze, with its body angled at 45°, the beetle catches fog droplets on its hardened wings. Its head faces upwind, and its stiff, bumpy outer wings are spread against the damp breeze. Minute water droplets (15-20 µm in diameter) from the fog gather on its wings; there the droplets stick to

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are no ...

(water-loving) bumps, which are surrounded by waxy,

hydrophobic In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, t ...

troughs. Droplets flatten as they make contact with the hydrophilic surfaces, preventing them from being blown by wind and providing a surface for other droplets to attach. Accumulation continues until the combined droplet weight overcomes the water's electrostatic attraction to the bumps as well as any opposing force of the wind; in a 30 km/h breeze, such a droplet would stick to the wing until it grows to roughly 5 mm in diameter; at that point it will roll down the beetle's back to its mouthparts. Researchers at the

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private Land-grant university, land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern t ...

have emulated this capability by creating a textured surface that combines alternating

and

materials. Potential uses include extracting moisture from the air and creating fog-free windows and mirrors. A company called NBD Nano is attempting to commercialize the technology. Lately, it has been shown that these beetles may also obtain water from dew (i.e. from humid air without fog).

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