Water vapor harvesting: Namib desert beetle

1 of 2 Stenocara gracilipes (Namib desert beetle) / Moongateclim.. / License

The wing covers of the Namib desert beetle gather water from the air using nanoscale bumps.

Biomimicry Taxonomy

	Get, store, or distribute resources >
	Capture, absorb, or filter >
	Liquids

Biomimetic Application Ideas

Create passive devices to collect water in dessicated environments for local consumption particularly in poor countries or for anyone needing to spend time in desert environments.

> Visit strategy page

[Collapse all sections] Summary

The Namibian Beetle (Stenocara gracilipes) lives in one of the driest deserts in the world, the Namib on the southwest coast of Africa, but obtains all of the water it needs from ocean fog due to the unique surface of its back. Microscopic bumps with hydrophilic (water attracting) tips and hydrophobic (water repelling) sides cover its hardened forewings, which it aims at oncoming fog each morning. Water droplets materialize out of thin air on its back, then slide down channels into its awaiting mouth. Synthetic surfaces mimicking the beetle’s back have been created that are several times more effective than existing fog-catching nets, and could be used to generate clean freshwater supplies in arid regions, refugee camps, and at the tops of skyscrapers, requiring no pumping.

Excerpt

The Namib Desert is characterized by high temperatures, strong winds, and negligible rainfall, but it does experience nocturnal and early morning fogs that move in from the Atlantic Ocean. The fog droplets are unusually small, about 1-40 microns in diameter (human hair is about 50 microns in diameter) so could easily be carried off by the hot desert wind. To capture these droplets before they're gone, the darkling beele faces into the wind and unabashedly sticks its rear end high in the air as if mooning all the beautiful creatures of the world, and starts to literally drink the fog as the droplets readily condense on its bumps and role down deliciously into its mouth. Observations suggest each beetle gains an average of about 12 percent of its body weight after fog-basking.

These clever darklings cover each 100-500 micron diameter bump with material that attracts water droplets (hydrophilic), while the area covering the 500–1,500 micron distance between each bump repels water (hydrophobic). As the tiny fog droplets cling to the top of each bump, they start to aggregate into bigger and bigger water droplets. At diameters of 4-5 mm, the weight of the droplet exceeds the forces attracting it in the first place, as well as the force of the desert wind, so it simply rolls off. Once in the trough between the forest of bumps, the droplet has no choice but to keep moving forward due the angle of the beetle's body and the waxy pavement. The highway system born of the configuration of bumps and troughs directs all traffic to the beetle's mouth. Take a closer look and you'll see that the waxy pavement of the troughs covers a microscopic hexagonal pattern of 10 micron diameter hemispheres, which together creates a superhydrophobic surface. In the hyperarid Namib Desert climate, he who fog-basks, laughs last. (Biomimicry Guild 2008)

Watch Video

About the inspiring organism

Namib desert beetle
Stenocara gracilipes

IUCN Red List Status: Unknown
Habitat(s): Desert

Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Bioinspired products and application ideas

Application Ideas: Create passive devices to collect water in dessicated environments for local consumption particularly in poor countries or for anyone needing to spend time in desert environments.

Industrial Sector(s) interested in this strategy: Utilities, recreation

Dew Bank Bottle - Water-collection and storage device

Fog-catching materials - Water-collecting surfaces

Fog-harvesting mesh - Fog-harvesting material

References

Naidu, S. G.; Hattingh, J. 1988. Water balance and osmoregulation in Physadesmia globosa, a diurnal tenebrionid beetle from the Namib desert. Journal of insect physiology. 34(10): 911-917.

Seely MK. 1979. Irregular fog as a water source for desert dune beetles. Oecologia. 42(2): 213-227.

Hamilton III, William J.; Henschel, Joh R.; Seely, Mary. 2003. Fog collection by Namid Desert beetles. South African Journal of Science. 99(3/4): 181.

Seely MK; Hamilton III WJ. 1976. Fog catchment sand trenches constructed by tenebrionid beetles, Lepidochora, from the Namib Desert. Science. 193(4252): 484-486.

Seely, Mary; Henschel, Joh R.; Hamilton III, William J. 2005. Long-term data show behavioural fog collection adaptations determine Namib Desert beetle abundance. South African Journal of Science. 101(11/12): 570-572.

Shanyengana, E. S.; Henschel, J. R.; Seely, M. K.; Sanderson, R. D. 2002. Exploring fog as a supplementary water source in Namibia. Atmospheric Research. 64(1-4): 251-259.

Seely, M. K.; Lewis, C. J.; O'Brien, K. A.; Suttle, A. E. 1983. Fog response of tenebrionid beetles in the Namib Desert. Journal of Arid Environments. 6(2): 135-143.

Hamilton, W. J.; Seely, M. K. 1976. Fog basking by the Namib Desert beetle, Onymacris unguicularis. Nature. 262(5566): 284-285.

Zhai, L.; Berg, M. C.; Cebeci, F. C.; Kim, Y.; Milwid, J. M.; Rubner, M. F.; Cohen, R. E. 2006. Patterned Superhydrophobic Surfaces: Toward a Synthetic Mimic of the Namib Desert Beetle. Nano Lett. 6(6): 1213-1217.

Ward, D.; Seely, M. K. 1996. Adaptation and Constraint in the Evolution of the Physiology and Behavior of the Namib Desert Tenebrionid Beetle Genus Onymacris. Evolution. 50(3): 1231-1240.

Water vapor harvesting: Namib desert beetle

Content tools

Curator of this page

Comments