Up until now, the research I’ve stumbled across about Tenebrionind beetles and their water-collecting ways has been from the US but this latest work comes from a France/Spain,/UK collaboration which focused on a specific question, exactly where do these beetles harvest their water from? A Dec. 8, 2014 news item on Nanotechnology Now describes this latest research,
Understanding how a desert beetle harvests water from dew could improve drinking water collection in dew condensers
Insects are full of marvels – and this is certainly the case with a beetle from the Tenebrionind family, found in the extreme conditions of the Namib desert. Now, a team of scientists has demonstrated that such insects can collect dew on their backs – and not just fog as previously thought. This is made possible by the wax nanostructure on the surface of the beetle’s elytra. … They bring us a step closer to harvesting dew to make drinking water from the humidity in the air. This, the team hopes, can be done by improving the water yield of man-made dew condensers that mimick the nanostructure on the beetle’s back.
It was not clear from previous studies whether water harvested by such beetles came from dew droplets, in addition to fog. Whereas fog is made of ready-made microdroplets floating in the air, dew appears following the cooling of a substrate below air temperature. This then turns the humidity of air into tiny droplets of water because more energy – as can be measured through infrared emissions – is sent to the atmosphere than received by it. The cooling capability is ideal, they demonstrated, because the insect’s back demonstrates near-perfect infrared emissivity.
Guadarrama-Cetina [José Guadarrama-Cetina] and colleagues also performed an image analysis of dew drops forming on the insect’s back on the surface of the elytra, which appears as a series of bumps and valleys. Dew primarily forms in the valleys endowed with a hexagonal microstructure, they found, unlike the smooth surface of the bumps. This explains how drops can slide to the insect’s mouth when they reach a critical size.
Here’s a link to and a citation for the paper,
Dew condensation on desert beetle skin by J.M. Guadarrama-Cetina, A. Mongruel, M.-G. Medici, E. Baquero, A.R. Parker, I. Milimouk-Melnytchuk, W. González-Viñas, and D. Beysens. Eur. Phys. J. E (European Physics Journal E 2014) 37: 109, DOI 10.1140/epje/i2014-14109-y
This paper is currently (Dec. 8, 2014) open access. I do not know if this will be permanent or if access rights will change over time.
My previous postings on the topic of water and beetles have focused on US research of the Stenocara beetle (aka Namib desert beetle) which appears to be a member of the Tenebrionind family of beetles mentioned in this latest research.
The European researchers have provided an image of the beetle they were examining,