Butterfly wings are not just beautiful. They are also sophisticated collectors of solar energy that help butterflies stay warm, and researchers say that their shinglelike structure could provide clues into developing better solar technology. Tongxiang Fan, a materials scientist at Shanghai Jiao Tong University in China, and his colleagues used an electron microscope to study the wing structure of two species of black butterflies and reported their findings at the American Chemical Society's meeting in San Diego. (They studied black wings because they absorb the maximum amount of sunlight.) They found that the wings are composed of elongated rectangular scales, arranged a bit like overlapping shingles. The scales also had steep ridges, with small holes on either side leading to a second layer. These features direct light to the second layer, helping the butterfly to capture a lot of heat. Fan said his team is now working to create a commercial product inspired by the wings.