Nature http://dx.doi.org/10.1038/nature16956 (2016)

What do you get when you cross a beetle with a cactus? If your guess was an optimal water harvester, you're on the money. Kyoo-Chul Park and colleagues have exploited natural design principles to come up with a technique that outperforms existing technologies for rapid droplet growth and delivery.

Namib desert beetles are adept at collecting water on their backs. But whereas much has been made of their surface chemistry, their shape — characterized by a back covered in bumps — has been largely overlooked. Park et al. demonstrated that this bumpy surface facilitated optimal condensation by constructing a biomimetic device. The rapid growth of the droplets was complemented by a refinement inspired by the spines of cacti: the apex geometry of the bumps was tuned to ensure fast directional transport while maintaining an optimal growth rate. These geometrical tricks were made even more efficient with a nanocoating technique motivated by the slippery surface of the pitcher plant.

The device can even operate in the presence of a temperature gradient, meaning its impressive growth and turnover rates may be applicable to water harvesting in regions subject to extreme climatic conditions.