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Water absorbed from humid air: brown dog tick


Brown dog tick / Alpha.prim / LicensePD - Public Domain

The mouths of ticks absorb water vapor from the atmosphere by secreting a hydrophilic solution.

"The ability to absorb water vapor from the atmosphere enables ticks to survive without drinking water for many months. The tick rehydrates using a three-stage process. First, it uses its foremost pair of legs to detect microregions of high humidity, such as those surrounding water droplets. Once a suitable water source is detected, the tick secretes a hydrophilic solution from its mouth. Once it is saturated, the tick draws the now hydrated secretion back into its mouth. The secretion is a hygroscopic salt solution. Once ejected from the mouth, the solution dries at low ambient humidities, leaving a crystalline substance behind. When the humidity increases, the hydrophilic crystalline substance dissolves and is swallowed back into the body of the tick. The adaptation allows exophilic ticks to absorb water vapor from close to saturation down to 43% relative humidity. Mites and soil-dwelling arachnids use a similar mechanism to absorb water vapor. This strategy might inspire innovation in the development of desiccants, building envelope design, and HVAC engineering." (Biomimicry Guild unpublished report)

"The salivary glands are the organs of osmoregulation in ticks and, as such, are critical to the biological success of ticks both during the extended period off the host and also during the feeding period on the host. Absorption of water vapour from unsaturated air into hygroscopic fluid produced by the salivary glands permit the tick to remain hydrated and viable during the many months between blood-meals. When feeding, the tick is able to return about 70% of the fluid and ion content of the blood-meal into the host by salivation into the feeding site. This saliva also contains many bioactive protein and lipid components that aid acquisition of the blood-meal. The salivary glands are the site of pathogen development and the saliva the route of transmission. The importance of the multifunctional salivary glands to tick survival and vector competency makes the glands a potential target for intervention." (Bowman and Sauer 2004:S67)

Close-up of the mouth parts of the brown dog tick showing secretion. When humidity rises above 41%, the hydrophilic secretion absorbs the moisture and is drawn back into the tick.
Artist: Emily Harrington. Copyright: All rights reserved. See gallery for details.

About the inspiring organism
Med_rhipicephalus_sanguineus_rotated Brown dog tick
Rhipicephalus sanguineus Latreille, 1806
Common names: Kennel tick, Tropical dog tick, Pan-tropical dog tick

Learn more at
Some organism data provided by: TicksBase
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

IUCN Red List Status: Unknown

Bioinspired products and application ideas

Application Ideas: Device that desiccates humid air before it enters a building to reduce energy needed in air conditioning (drier air, less cooling needed). Might even be a source of water for flushing toilets, etc. Device that keeps cold engine parts from sweating by removing moisture from air--reduces need for biocides against moisture-loving bacteria. Device that gathers water from humid air for drip irrigation. Osmotic solution could be used to channel moisture away from sensitive electronic parts or moisture sensitive packaged goods, or could be adapted for microfluidic devices.

Industrial Sector(s) interested in this strategy: Building, manufacturing, agriculture, electronics, packaging

School of Biological Sciences
Alan Bowman
University of Aberdeen
Gaede K; Knülle W. 1997. On the mechanism of water vapour sorption from unsaturated atmospheres by ticks. Journal of Experimental Biology. 200(10): 1491-1498.
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Bowman AS; Sauer JR. 2004. Tick salivary glands: functions, physiology and future. Parasitology. 129: S67-S81.
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over 5 years ago
Thanks to Emily Harrington for creating this illustration to explain the biological principle.
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