You’ve probably been out by the water on a warm summer day when you noticed something skimming across the top of the nearby lake. Upon closer inspection you see that it’s indeed a small insect that is able to effortlessly glide across water. Personally, this fascinates me, so I dug a little deeper to better understand how the water strider is capable of this biblical feat.
Water striders are of the family Gerridae, are only about half an inch long, and possess six legs. These six legs have a number of hairy projections called setae that are hydrophobic (2).Up until this point, scientists had believed that the water strider’s ability to glide on water was due to a was it secreted by the cuticle, however recent research by Xuefang Gao and Lei Jiang has indicated that this is not the case. These researchers believe the ability to effortlessly walk on water is the result of the heirarchial structure of many small microsetae on the insect’s legs that give it a sort of “superhydrophobicity.” They found that the water strider is able to withstand a force of up to 15x its body weight before drowning. Gao and Jiang hope that this knowledge can be used in the future to create water-resistant, drag reducing materials (1).
While there are currently a number of rain repellant products, many pale in comparison to the superhydrophobicity of a water strider leg. Maybe in the future a water resistant coating could be added to cars? Or maybe something as simple as super-water resistant umbrellas will be a commonality? Only time will tell.
(1) Gao X, Jiang L. Biophysics: Water-repellent legs of water striders. Nature [serial online]. November 4, 2004;432(7013):36. Available from: Academic Search Premier, Ipswich, MA. Accessed November 18, 2013.
(2) Water Strider: National Wildlife Federation http://www.nwf.org/Wildlife/Wildlife-Library/Invertebrates/Water-Strider.aspx
(3) Walking on Water: Insect’s Secrets Revealed http://www.livescience.com/62-walking-water-insect-secret-revealed.html