Archive for March, 2011
Eye to Eye
Thursday, March 3rd, 2011Look deep into my eyes. What do you see? My inner soul? True feelings? Hang on. I’m not that romantic. Let me share with you the non-existential angle of eye gazing.
lacewing; photo by Sonya Vickers
My friend was curious about looking closely at the compound eye of a lacewing. She slowed him down by putting the dish he was in on a bed of snow. With the aid of a handheld digital microscope she could get a pretty close look.
lacewing compound eyes; photo by Sonya Vickers
A compound eye is made of of a lot – could be thousands – of individual light sensors called ommatidia. Each one, arranged on a spherical surface points in a slightly different direction, catching light from that specific angle. The resulting image is a mosaic of light and dark spots. Much like pixilation, the more ommatidia, the better resolution of the image. Grasshoppers have comparatively few ommatidia, and their images are coarser grained as compared to a honeybee or dragonfly. But, because a moving image is caught by many ommatidia in a sequence, a compound eye is great at detecting motion over a wide field of view. Some insects, like the honeybee have visual cells in the ommatidia that can detect certain colors. Bees and butterflies among others can see ultraviolet light too. These abilities help them identify nectar-rich flowers for nutrition.
compound eye of a lacewing; photo by Sonya Vickers
Anyway, my friend and I were just fascinated with the reflective/refractive properties of our lacewing’s eyes. A regular rainbow of color. I hope you like gazing into his eye.