Mood Bugs: Beetle changes color in fluid fashion
Color-changing animals, such as chameleons and squid, typically alter their hues when nerve signals or hormones spur pigment cells in their skin to expand or shrink.
The Panamanian golden tortoise beetle, however, changes color dramatically from metallic gold to matte red by a very different method, researchers report. It uses its body fluid to structurally alter the reflectivity of its shell—a trick that could one day be built into devices that would optically signal the presence of a liquid.