The Water-collecting Mechanism of Moloch horridus Re-examined

Gans, Carl; Merlín, R.; Blumer, W.

doi:10.1163/156853882x00167

Cited by 52 publications

(33 citation statements)

References 3 publications

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“…In capillary channels formed by partially overlapping (imbricate) scales, collected water is transported further to the snout where active water ingestion takes place [7,8,9,10]. These channels have a narrow opening on their superfi cial side and thus form a semi-tubular capillary system over the entire lizard's body [7].…”

Section: Introductionmentioning

confidence: 99%

Laser-Based biomimetic functionalization of surfaces: from moisture harvesting lizards to specific fluid transport systems

Comanns¹,

Winands²,

Arntz³

et al. 2014

Int. J. DNE

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Inspirations found in nature became more and more famous for an innovative product development. An interdisciplinary approach of scientifi c research and industrial development has shown that identifi cation and transfer of biological principles to technical applications uncover secrets of specifi c adaptations resulting in innovations with remarkable potential.Investigating the functional morphology of moisture harvesting lizards revealed the underlying principles of an adaptation to a life in arid environments. To survive water scarcity these lizards have developed different water catchment strategies. Special skin structures enable them to acquire water from moist substrate and transport the collected water to the snout. The former is a micro ornamentation, which can hold a water fi lm to render the surface superhydrophilic, the latter is a network of half-open capillary channels that transports the collected water. Transferring these structures to a producible structure design and to technical surfaces requires a fundamental understanding of the biological principles as well as an abstraction and modifi cation. Additionally enabling manufacturing technologies like laser structuring are needed to realize a functional surface structuring on complex shaped products. It is concluded that a biomimetic liquid transport can increase the product performance, improves product life time or saves resources.

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Section: Introductionmentioning

confidence: 99%

Laser-Based biomimetic functionalization of surfaces: from moisture harvesting lizards to specific fluid transport systems

Comanns¹,

Winands²,

Arntz³

et al. 2014

Int. J. DNE

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“…Water is transported passively in the half-open capillary channels between the scales by capillary force (Bentley and Blumer, 1962;Gans et al, 1982;Withers, 1993;Sherbrooke et al, 2007;Comanns et al, 2011). As soon as water reaches the scales surrounding the mouth, the lizard can but does not necessarily drink.…”

Section: Drinking From Water Puddlesmentioning

confidence: 99%

“…Special surface micro-structures of the Oberhäutchen (i.e. outer layer of epidermis) and small capillary channels in between the scales allow these so-called 'moistureharvesting' lizards to collect water into their skin capillaries and transport it to their mouth for drinking (Gans et al, 1982;Withers, 1993;Sherbrooke, 2004;Sherbrooke et al, 2007;Comanns et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Based on their stereotypic skin drinking posture, Phrynosoma, Trapelus and Phrynocephalus likely specialize on drinking rain water (Schwenk and Greene, 1987;Sherbrooke, 1993Sherbrooke, , 2004Veselý and Modrý, 2002). Water puddles are probably an effective water source for M. horridus, although they are not commonly found in their sandy habitat (Pianka and Pianka, 1970;Gans et al, 1982;Withers, 1993). Thorny devils and horned lizards placed in a water puddle readily uptake water via capillary channels, which they subsequently drink (Bentley and Blumer, 1962;Withers, 1993;Sherbrooke, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…The specialized epidermal structure of moisture-harvesting lizards might facilitate such condensation, e.g. the spiny scales of M. horridus have been suggested to act as condensation foci (Gans et al, 1982). Condensation of humid air has also been suggested to occur for the less spiny lizard Phrynocephalus helioscopus (Schwenk and Greene, 1987), and a tropical tree frog (Tracy et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Cutaneous water collection by a moisture-harvesting lizard, the thorny devil (Moloch horridus)

Comanns

Withers

Esser

et al. 2016

Journal of Experimental Biology

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Moisture-harvesting lizards, such as the Australian thorny devil, Moloch horridus, have the remarkable ability to inhabit arid regions. Special skin structures, comprising a micro-structured surface with capillary channels in between imbricate overlapping scales, enable the lizard to collect water by capillarity and transport it to the mouth for ingestion. The ecological role of this mechanism is the acquisition of water from various possible sources such as rainfall, puddles, dew, condensation on the skin, or absorption from moist sand, and we evaluate here the potential of these various sources for water uptake by M. horridus. The water volume required to fill the skin capillary system is 3.19% of body mass. Thorny devils standing in water can fill their capillary system and then drink from this water, at approximately 0.7 µl per jaw movement. Thorny devils standing on nearly saturated moist sand could only fill the capillary channels to 59% of their capacity, and did not drink. However, placing moist sand on skin replicas showed that the capillary channels could be filled from moist sand when assisted by gravity, suggesting that their field behaviour of shovelling moist sand onto the dorsal skin might fill the capillary channels and enable drinking. Condensation facilitated by thermal disequilibrium between a cool thorny devil and warm moist air provided skin capillary filling to approximately 0.22% of body weight, which was insufficient for drinking. Our results suggest that rain and moist sand seem to be ecologically likely water sources for M. horridus on a regular basis.

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Novel Water Harvesting Fibrous Membranes with Directional Water Transport Capability

Zhou

Wang

et al. 2019

Adv Materials Inter

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properties assisted in moisture absorption. The Namib Desert beetles and Texas horned lizard collect dew using their bumpy body surface with alternating regions of hydrophilic and hydrophobic, and the honeycomb structures on the scale increase condensation foci. [3][4][5][6] These excellent water harvesting creatures elucidate the critical role of wettability irregularity and hierarchical structure gradient in guiding water transport. [7] Inspired by nature, researchers have developed artificial water harvesters, [7][8][9][10][11][12][13][14][15][16][17][18] such as water collecting filaments and hydrophobichydrophilic patterned fog collectors. [19][20][21][22] However, most of the water harvesters developed so far are based on either a 2D surface or a 1D filament.Recently, researchers have uncovered that porous membranes with wettability gradient or wettability contrast in thickness direction can have a "smart" directional wicking effect, which enables water to transfer automatically across the membrane just in one direction. [23][24][25][26][27][28][29][30] Our previous works have reported the preparation of hydrophobic-to-hydrophilic gradient fabrics that can guide directional water-transport from the hydrophobic to the hydrophilic side. [31,32] Such a unidirectional water penetration phenomenon was also reported by other researchers. In research literatures, the directional water transport was also termed "one-way water transport," "directional wicking," [33][34][35] or "water diode." [36][37][38][39][40] Almost all the directional water transport membranes have a hydrophobic layer on one side and a hydrophilic layer on the other, a typical feature of Janus membranes. However, not all Janus membranes have a directional wicking property because Janus membranes might have bidirectional or nonwicking properties, depending on the hydrophobic/hydrophilic combination layout. [36,38,39] Despite the reports about the preparation and applications of directional wicking porous media, limited attention has been devoted to using them for water harvesting.Herein, we report a novel finding about harvesting water from air using hydrophobic/superhydrophilic directional wicking nanofibrous membranes. A two-step electrospinning method was employed to prepare directional wicking fibrous membranes using polyacrylonitrile (PAN) as a starting material. The directional wicking membranes were found to have much larger water harvesting capacity than those with homogeneous wettability and the same fibrous structure. The porous structure and pore dimension also contributed to water harvesting.Previous studies about water harvesting from airborne moisture, which is driven by a directional water transport principle, are based on either a 2D surface or a 1D filament. Porous membranes with a directional water transport capability are seldom used for water harvesting. Herein, a novel hydrophobic/ hydrophilic directional-wicking nanofibrous membrane is reported showing enhanced water harvesting ability. In comparison to the hydrophobic or hy...

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The Water-collecting Mechanism of Moloch horridus Re-examined

Cited by 52 publications

References 3 publications

Laser-Based biomimetic functionalization of surfaces: from moisture harvesting lizards to specific fluid transport systems

Laser-Based biomimetic functionalization of surfaces: from moisture harvesting lizards to specific fluid transport systems

Cutaneous water collection by a moisture-harvesting lizard, the thorny devil (Moloch horridus)

Novel Water Harvesting Fibrous Membranes with Directional Water Transport Capability

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