The small structures in the scanning electron microscope image of a butterfly wing scale (a) are natural photonic crystals that give the wings of some butterflies their brilliant iridescent blue colors. The structures in the second image (b) are responsible for a blue-violet iridescence. In the third image (c), the small structures are almost entirely absent, and the butterfly wing scales are a dull brown shade. New research suggests that photonic crystals keep butterfly wings cooler, as well as making them beautiful. In higher elevations where butterflies are more reliant on sunlight to keep them warm, some of the insects have evolved wing scales in which the photonic crystals have been disrupted (as in image c), improving the chances that they survive long enough to mate despite the frigid climate.
Source: L. P. Biro et al., Physical Review E, February 2003
In recent years, scientists have discovered that the iridescence of various colorful creatures, from beetles to birds to butterflies, is often due to microscopic structures known as photonic crystals. Unlike pigments, which absorb or reflect certain frequencies of light as a result of their chemical composition, the way that photonic crystals reflect light is a function of their physical structure. That is, a material containing a periodic array of holes or bumps of a certain size may reflect blue light, for example, and absorb other colors even though the crystal material itself is entirely colorless. Because a crystal array looks slightly different from different angles (unlike pigments, which are the same from any angle), photonic crystals can lead to shifting shades of iridescent color that may help some animals attract mates or establish territories.
A collaboration of researchers from Hungary and Belgium (Jean-Pol Vigneron, Universitaires Notre-Dame de la Paix, Brussels, firstname.lastname@example.org, 011+32-81 724711) may have discovered why the males in certain populations of lycaenid butterflies carry the striking, photonic crystal coloration, and males in other lycaenid populations do not. The researchers examined butterfly scales through high-resolution scanning electron microscopes (see image), and confirmed that indeed the colorful butterflies’ scales included arrays of submicron-sized holes that formed natural photonic crystals. Their closely related brethren from higher elevations did not have the hole arrays in their scales, and their wings were dull brown rather than iridescent blue. The difference, it seems, may be due to a question of survival. The researchers found that the plain brown butterfly wings warmed much more than the iridescent blue wings when each were exposed to identical illumination. The researchers believe that the butterflies at high elevations trade flashy iridescence for light-absorbing brown so that they can withstand colder temperatures, and survive long enough to mate.
If photonic crystals can have such a dramatic impact on butterfly thermal management, suggest the researchers, manmade photonic crystals may someday provide flexible thermal protection in extreme environments, possibly being incorporated into such things as space suits or desert garments. (L. P. Biro et al, Physical Review E, February 2003; text www.aip.org/physnews/select )
Phil Shewe | Bulletin of Physics News
The moon is front and center during a total solar eclipse
24.07.2017 | NASA/Goddard Space Flight Center
Superluminous supernova marks the death of a star at cosmic high noon
24.07.2017 | Royal Astronomical Society
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
24.07.2017 | Power and Electrical Engineering
24.07.2017 | Materials Sciences
24.07.2017 | Materials Sciences