I am used to seeing Common Green Darner (Anax junius) dragonflies flying overhead, but on Tuesday I had the relatively rare chance to see one up close at Occoquan Regional Park. The Common Green Darner is a large, colorful dragonfly that is known for its long distance migratory flights. According to Wikipedia, “By attaching micro-radio transmitters to Common Green Darners, researchers have found them to be capable of migrating up to 140 kilometers in a day, though they typically cover less distance per day. ” Wow!
I spotted this dragonfly when I saw it fly to a perch in the vegetation just inches above the ground. I slowly made my way towards the vertically-perched Common Green Darner and surprisingly it did not move. I am not certain, but I had the impression that the dragonfly had newly emerged and was resting as its body parts dried out.
My 180mm macro lens gives you the impression that I was right on top of the dragonfly, but I was actually quite a bit farther away than it seems. After I took a few shots and moved away, the Common Green Darner remained in place. In fact, when I passed by the same area about twenty minutes later, it was still perched there.
I was thrilled by the amount of detail that I was able to capture. You can easily see the distinctive “bullseye” marking, for example, on the “face” of the dragonfly. The second image is a closer crop of the first image and it helps you to see some of the ommatidia, the thousands of faceted optical units that make up the dragonfly’s amazing compound eyes. You may want to click on the image to make it larger on your screen.
According to an on-line article called Dragonfly’s Eyes, “Dragonflies have very large eyes and have very good vision. Vision dominates their behaviour, including predation and looking for mates. The compound eye is made up of ommatidia which is a visual unit consisting of a lens system and a group of light sensitive cells. A large dragonfly may have up to 30,000 ommatidia in each compound eye. Each ommatidium collects one visual information, together form a mosaic image in the dragonfly’s brain. It is believed that the insects’ compound eyes are not as high resolution as vertebrate eyes. However, the dragonfly’s visual system is extremely sensitive to movement and it points in almost all direction and gives the 360 degree visual field.”


© Michael Q. Powell. All rights reserved.
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