Monday, February 13, 2017

Off The Charts In Guyana - Blue Morpho Butterfly

Poster at Kaieteur Falls

I can't leave our Guyana adventure story without telling you more about the Blue Morpho Butterfly.  These are the bright, electric blue butterflies we first saw at Marshall Falls and then up the creek.  They are HUGE (3" to 8" wingspan) and simply stunning.  The color is so hard to describe.  Of course being butterflies, you can't really take a picture of them because they are fluttering this way and that.  Is it just me, or do butterflies sort of seem like the happy drunks of the insect world?  Often it is said butterflies dance along but they just seem tipsy to me.  They can't fly in a straight line at all but nobody cares because they make you smile.

Anyway, back to the color.  It is breathtaking.  So much so that I had to look them up on the internet.  It turns out there is way more to that magical blue coloring than meets the eye.  Here is some of what Wikipedia had to say about it.  "Many morpho butterflies are colored in metallic, shimmering shades of blues and greens. These colors are not a result of pigmentation, but are an example of iridescence through structural coloration. Specifically, the microscopic scales covering the morpho's wings reflect incident light repeatedly at successive layers, leading to interference effects that depend on both wavelength and angle of incidence/observance.[7] Thus, the colors appear to vary with viewing angle, but they are actually surprisingly uniform, perhaps due to the tetrahedral (diamond-like) structural arrangement of the scales or diffraction from overlying cell layers. The wide-angle blue reflection property can be explained by exploring the nanostructures in the scales of the morpho butterfly wings.[8] These optically active structures integrate three design principles leading to the wide-angle reflection: alternative lamellae layers, Christmas tree-like shape, and zigzag pattern of the ridges. The reflection spectrum is found to be broad (about 90 nm) for alternating layers and can be controlled by varying the design pattern. The Christmas tree-like pattern helps to reduce the directionality of the reflectance by creating an impedance matching for blue wavelengths. In addition, the zigzag pattern of ridges destroys the unwanted interference for other wavelengths in wide angle. This structure may be likened to a photonic crystal. The lamellate structure of their wing scales has been studied as a model in the development of biomimetic fabrics, dye-free paints, and anticounterfeit technology used in currency.
The iridescent lamellae are only present on the dorsal sides of their wings, leaving the ventral sides brown.  " 
Kewl huh?  If you want to learn more about these amazing insects, read it here Blue Morpho Butterfly

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