Research by Park et al. (2016) published in the journal Nature
combined features from other organisms that capture water from the air, including the directionality of cactus spines, to arrive at a slightly different bump shape. We looked at shapes similar to theirs to see if this directionality, and the capillary action associated with the canyon-like character to the bumps, would increase the rate of condensation. Simulations involved sending a slight breeze of humid air across the surfaces (to match the conditions the beetle is in as it assumes a “fog basking” position). Water condenses on the surface and rolls off into a cistern. We rank the tiles by both the total volume of water condensed and by the total volume divided by their surface areas (to understand the influence purely from geometry—without a bias toward surfaces with larger surface areas).
Our preliminary results suggest that bumps can increase the rate of condensation, even when we correct for the increase surface area they represent. But this is not always the case. The specific size and spacing matters a great deal. Our results also suggest that asymmetric bumps perform better (relative to rate of condensation) when compared to spherical bumps—as hypothesized and demonstrated by Park et al. (2016).
This is a work in progress. There’s so much more we’d like to explore and understand related to evolved geometries that specialize in water capture.