A terrestrial leaf beetle can walk underwater, thanks to tiny air bubbles trapped between hair-like structures on its feet.
Gastrophysa viridula (pictured) use these 'hairs', or setae, and the secreted fluid that covers them, to stick to leaves when on land. Naoe Hosoda at the National Institute for Materials Science in Tsukuba, Japan, and Stanislav Gorb at the University of Kiel in Germany found that when the animals walk underwater, air bubbles remain trapped between the setae. The bubbles not only provide adhesion but also de-wet the area around the beetles' feet, enabling the setae to function as they do on land.
On the basis of these principles, the researchers were able to develop an artificial polymer that successfully kept small objects attached to vertical surfaces underwater.
Proc. R. Soc. B http://dx.doi.org/10.1098/rspb.2012.1297 (2012)
For a video linked to this research, see go.nature.com/ecyztv