The Beetles That Drink Water From Air

Biological Strategy

Darkling beetles

AskNature Team

Image: James Anderson / CC BY NC SA - Creative Commons Attribution + Noncommercial + ShareAlike

Capture, Absorb, or Filter Liquids

The most common liquid used by living systems is water, which they require to survive. But there are many other liquids that provide nourishment, play a role in defense mechanisms, or serve other purposes. Water varies in its availability; it is sometimes plentiful and sometimes very scarce or only available as fog or mist. To minimize the energy required to capture, absorb, or filter liquids, living systems have strategies that take advantage of the unique properties of the given liquid. For example, water moves from a gaseous to liquid state when it encounters a surface colder than the air. Plants in forests that experience fog and clouds more than rain have strategies that condense liquid water from moist air.

Search this Function

Adapt Behaviors

The environment is constantly changing, and if living systems can’t adapt to these changes, they don’t survive. Environmental changes can be cyclic such as seasons, sudden such as floods or forest fires, or gradual but long-term, such as ecosystems shifting from early to mature stages. These changes require some flexibility in behavioral responses to match the specific conditions. For example, as a fish called the lamprey swims, it constantly faces changes in currents. Skin sensors help it detect those changes and adjust its motion accordingly.

Search this Function

Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

Search this Living System

Darkling beetle wing covers and body postures help condense water from humid air.

Introduction

Darkling beetles (family Tenebrionidae) of the Namib Desert, located on the southwest coast of Africa, live in one of the driest habitats in the world. But some species of darkling beetle can get the water they need from dew and ocean fog, using their very own body surfaces.

The Strategy

Several researchers are studying the beetles, as well as synthetic surfaces inspired by the beetle’s body, to uncover the roles that structure, chemistry, and behavior play in capturing water from the air.

Micro-sized grooves or bumps on the beetle’s hardened forewings can help condense and direct water toward the beetle’s awaiting mouth, while a combination of hydrophilic (water attracting) and hydrophobic (water repelling) areas on these structures may increase fog- and dew-harvesting efficiency. For certain species of darkling beetle, the act of facing into the foggy wind and raising its rear end up in the air (known as fog-basking behavior) is thought to be just as important as body surface structure for successfully harvesting water from the air.

Image: James Anderson / CC BY NC SA - Creative Commons Attribution + Noncommercial + ShareAlike

For certain species of Darkling beetle, the act of facing into the foggy wind and raising its rear end up in the air is thought to be critical to its ability to harvest water.

Image: Professor Andrew Parker / CC BY NC ND - Creative Commons Attribution + Noncommercial + NoDerivatives

Zooming in, the textured surface of the darkling beetle's overwing becomes apparent.

The combined act of raising its rear to increase contact with the air as well as surface structures that enhance water condensation allow the beetle to harvest water and survive in extremely arid conditions.

The Potential

According to the World Wildlife Fund, 10% of all animals depend on freshwater habitats that occupy a mere 1% of the surface of our planet. And these scant resources are increasingly jeopardized by development, pollution, and climate change. As global temperatures rise, more water absorbs into the atmosphere, raising humidity and providing additional warming in a process called “water vapor feedback.”

Darkling beetles’ method of harvesting water from the atmosphere could help humans gather fresh water in remote areas that lack access to surface water. It may also inspire more efficient evaporative cooling designs that reduce water consumption in power plants and industrial facilities. Perhaps learning how to efficiently remove water from the atmosphere could even provide a means of slowing or stopping water vapor feedback, helping us mitigate rising global temperatures.

Related Innovations

Innovation: Industry

Fog-Harvesting Material Inspired by the Desert Beetle

Infinite Cooling

Infinite Cooling captures vapor from cooling towers to reduce water usage.

Innovation: Industry

Lightweight Water Collection System Inspired by Darkling Beetles

Warka Water

Warka Tower from Warka Water uses a mesh net to collect water from humid air.

Related Strategies

Biological Strategy

Inky cap

Ballistospores of fungi are catapulted away by coalescence of water droplets.

Last Updated February 7, 2017

References

Journal article

Water balance and osmoregulation in Physadesmia globosa, a diurnal tenebrionid beetle from the Namib desert

Journal of Insect Physiology | 24/10/2003 | S.G. Naidu, J. Hattingh

embedly preview

Reference

“The Namib Desert has a remarkably high variety of Darkling beetles (Tenebrionidae) and a handful of them actively exploit fog for water intake [5,6]. Some of these construct sand trenches or ridges to catch the fog, while Onymacris unguicularis and O. bicolor instead utilise their own body surface as a fog water collector [7-9]. By adopting a head standing posture facing into the wind, the fog water collects on their elytra and runs down to their mouth, to be imbibed by the beetles. This unique behaviour is termed fog-basking [7]. The advantage of fog collection for water intake in the extremely arid desert is obvious, and becomes critical when rainfall is absent over prolonged periods of time. Long term studies on the population density of Darkling beetles in the Namib Desert clearly shows that the fog collecting beetles are still present in great numbers during periods of low rain fall, whereas the large majority of Darkling beetles that lack this adaptation disappear or decline to less than 1% of their mean abundance [5].” (Norgaard and Dacke 2010:1-2)