Desert beetles survive by funneling fog along the dimpled back of its exoskeleton and into their mouths, providing a cool morning drink in an otherwise bone-dry environment. A similar pattern of water-loving bumps and water-repellant troughs, scientists argue, could have a wide range of applications in industry, from farming to aviation.
Stenocara beetles live in the hottest place in the world, the Namib desert in southwest Africa, where the only available water is fog. Scientists knew that the beetles collected fog by facing into a stiff morning breeze and tilting their bodies forward, but didn't understand how this trapped drinking water. Now, in a paper in the 2 November issue of Nature, a pair of researchers describe a system of water-attracting peaks and waxy valleys that enable the animals to survive.
Zoologist Andrew Parker of the University of Oxford, United Kingdom, was searching for reflectors in the Stenocara exoskeleton that might help it stay cool, when he noticed a random patchwork of water-loving and water-repelling regions. Fine mist, he discovered, bounces off the valleys and sticks to the peaks, where it forms beads fat enough to roll against the wind, down the thirsty beetle's back, and into its mandibles.
Parker and Chris Lawrence, from the government-owned company QinetiQ in Hampshire, U.K., confirmed the efficiency of the design by making glass microscope slides that mimicked this pattern and spraying them with fine mist. The team has applied for a patent on using larger versions of the patterned surfaces to capture wind-blown fog. They say the technique could harvest water for drinking and farming, reduce unwanted condensation during chemical manufacture, and even clear fog from around airports.
The success of this design will depend on how well the beetle-sized system scales up, says Julian Vincent, who studies biomimetic engineering at the University of Bath, U.K. But Vincent says he's glad to see scientists getting inventions from nature again, a tradition that lapsed after the clingy hooks of the burdock plant inspired the creation of Velcro in 1948. "Hardly anybody has tried doing anything like that since then," he says.