Directional textured surfaces in nature. (a) Beetle (Hemisphaerota cyanea) tarsus consists of pads arranged in rows (left) and stuck together in clusters (middle, right). Scale bars, left to right, 200 µm, 40 µm, 10 µm. Source: Eisner and Aneshansley,[17] copyright (2000) National Academy of Sciences, U.S.A. (b) Tokay gecko (Gekko gecko) foot setae (left) and the finest terminal branches of a seta, called spatula (right). Scale bars 50 µm (left) and 1 µm (right). Source: Autumn et al.,[66] reprinted with permission from Macmillan Publishers: Nature, copyright 2000. (c) Wet-rebuilt silk of the cribellate spider (Uloborus walckenaerius), showing overall structure (top) with ESEM zooms of a spindle knot (bottom left) and joint (bottom right). Scale bars 50 µm (top) and 2 µm (bottom). Source: Zheng et al.,[23] reprinted with permission from Macmillan Publishers: Nature, copyright 2010. (d) The non-wetting leg of the water strider (Gerris remigis). Individual hairs are deflected by capillary forces as the drop advances against the grain (top). SEM images of the oriented microsetae (bottom left) and the nanoscale grooved structures on a seta (bottom right). Scale bars 100 µm (top), 40 µm (bottom left), 400 nm (bottom right). Top image reprinted from Prakash et al.,[24] copyright (2011), with permission from Elsevier. Bottom image from Gao and Jiang,[25] reprinted with permission from Macmillan Publishers: Nature, copyright 2004. (e) Overlapping microscales (top) on the wings of the butterfly (Morpho aega) are comprised of aligned nanostripes. Scale bars 100 mm (top) and 400 nm (bottom). Source: Zheng et al.,[28] reproduced by permission of The Royal Society of Chemistry. (f) Peristome surface of the Nepenthes pitcher plant has first and second order radial ridges. Scale bars 100 µm. Source: Bohn and Federle,[29] copyright (2004) National Academy of Sciences, U.S.A. (g) Micro-barbs on the surface of the grass species Hordeum murinum. Scale bar 50 µm. Source: Kulic et al.,[30] reprinted with permission of The Royal Society, copyright 2009.