Namib Desert beetle

Namib Desert beetle
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Family:	Tenebrionidae
Genus:	Stenocara
Species:	S. gracilipes
Binomial name
Stenocara gracilipes

The Namib Desert beetle dwells in one of the most arid areas with only one and half inch (40 mm) of rain per year, and has developed a unique technique to survive by obtaining water from early morning fogs. It drinks by the means of its own bumpy back surface, which provides for accumulation of water droplets of fifteen to twenty micrometers in diameter.The beetle has long spindely legs.

To drink water, the Namib beetle (genus Stenocara) stands on a small ridge of sand. Facing into the breeze, with its body angled at forty-five degrees, 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 from the fog gather on its wings; there the droplets stick to hydrophilic bumps, which are surrounded by waxy, hydrophobic troughs. Droplets accumulate and coalesce until their combined weight overcomes the water's electrostatic attraction to the bumps as well as any opposing force of the wind; in a ten-mile-an-hour breeze, such a droplet would stick to the wing until it grows to roughly two-tenths of an inch in diameter; at that point it would roll down the beetle's back to its mouth parts.

The water droplets in fog are, on average, just one one-thousandth of an inch across, and the largest ones are only twice that size. The droplets are so small, in fact, that they often don't fall downward; instead they get carried sideways or even upward by currents of wind.The trick to drinking fog is getting the droplets to aggregate, so that wind and electrostatic forces no longer overwhelm gravity. When a wind-blown fog droplet lands on a hydrophilic (water-loving) surface, such as clean glass or stone, the drop flattens out because of the electrostatic attraction between the molecules of water and those of the surface. The cross section of the flat drop is too small for the wind to pick it back up. And, because water molecules so strongly attract each other, the flat drop also presents a highly hydrophilic surface to which other droplets can attach.^[1]

Researchers at the Massachusetts Institute of Technology have emulated this capability by creating a textured surface that combines alternating hydrophobic and hydrophilic materials. Potential uses include extracting moisture from the air^[2] and creating fog-free windows and mirrors.

References

1. ^ http://biomechanics.bio.uci.edu/_html/nh_biomech/namib/beetle.htm
2. ^ [1]

• Parker, A. R. & C. R. Lawrence (2001). "Water capture by a desert beetle". Nature 414 (6859): 33–34. doi:10.1038/35102108. PMID 11689930. 
• Harries-Rees, Karen (August 31, 2005). "Desert beetle provides model for fog-free nanocoating". Chemistry World News (Royal Society of Chemistry). http://www.rsc.org/chemistryworld/News/2005/August/31080502.asp. 
• "Stenocara beetle". Biomimicry Guild. http://database.biomimicry.org/item.php?table=organism&id=1010. Retrieved 2006-12-14.