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Skin hydrophobicity as an adaptation for self-cleaning in geckos

Citation

Riedel, Jendrian; Vucko, Matthew; Schwarzkopf, Lin; Blomberg, Simone (2021), Skin hydrophobicity as an adaptation for self-cleaning in geckos, Dryad, Dataset, https://doi.org/10.5061/dryad.xwdbrv19s

Abstract

Hydrophobicity is common in plants and animals, typically caused by high relief microtexture functioning to keep the surface clean. Although the occurrence and physical causes of hydrophobicity are well understood, ecological factors promoting its evolution are unclear. Geckos have highly hydrophobic integuments. We predicted that, because the ground is dirty and filled with pathogens, high hydrophobicity should coevolve with terrestrial microhabitat use. Advancing contact angle (ACA) measurements of water droplets were used to quantify hydrophobicity in 24 species of Australian gecko. We reconstructed the evolution of ACA values, in relation to microhabitat use of geckos. To determine the best set of structural characteristics associated with the evolution of hydrophobicity, we used linear models fitted using phylogenetic generalized least squares (PGLS), and then model averaging based on AICc values. All species were highly hydrophobic (ACA > 132.72°), but terrestrial species had significantly higher ACA values than arboreal ones. The evolution of longer spinules and smaller scales were correlated with high hydrophobicity. These results suggest that hydrophobicity has co-evolved with terrestrial microhabitat use in Australian geckos via selection for long spinules and small scales, likely to keep their skin clean and prevent fouling and disease.

Methods

For details of data collection see methods section of the paper.

Usage Notes

Each number is a single measurement of one water drop for the respective gecko specimen.