Showing posts with label Brown-spotted Yellow-wing. Show all posts
Showing posts with label Brown-spotted Yellow-wing. Show all posts

Thursday, August 27, 2009

The stylish pleats on a dragonfly’s wings provide more than just a snappy look!

When I was out in the field photographing the dragonflies, I didn’t know their wings were pleated. I just knew their wings were gorgeous and I wanted a closer look at them, so I started focusing the lens on the wings at different angles, trying to capture the patterns of veining and their thin, delicate beauty. It wasn't until I downloaded the photos and started studying them that I noticed the wings were pleated like corrugated steel or cardboard!

If you look carefully, you can see pleats in the middle of the wing.

Looking straight on, it's easy to see the zig-zaggy ripples.

Intricate, lacy veining...beautiful.

When you're not zoomed in you barely
notice the corrugation, but it's there!

Of course I wanted to know why those wings were zig-zaggy, so I did a quick Google search. The first article that popped up was "A computational study of the aerodynamic performance of a dragonfly wing section in gliding flight," by Abel Vargas, Rajat Mittal and Haibo Dong. That sounded promising, so I read it and found some pretty cool info. If you want to read the entire paper, click here. Published on May 23, 2008, these aerospace engineers from The George Washington University found through a simulated study of pleated and non-pleated wings that the pleats in a dragonfly's wings are a unique adaptation, or in their words, "an ingenious design of nature," that can help produce more lift than a smooth wing. The reason being air circulation between the pleats results in less drag, which is good for gliding (and dragonflies do a lot of that!).

Isn't that cool? What started as an attraction to the lacy, delicate beauty of the veining and iridescence of the wings, turned into another AWE of Mother Nature. She always does know what she’s doing……

I wonder if I can design a super-duper paper airplane with this information! :-)

Tuesday, August 25, 2009

A dragonfly! My guess...a Brown-spotted Yellow-wing, commonly called a Halloween pennant!

I headed over to Voice of American (VOA) Park today. It had been over two weeks since I'd been there, and I couldn't wait to visit the High Meadow. I've really become attached to the open grassland habitat. I love the wildflowers, the sun, and the insect sounds. Today I was hoping for butterflies. The last time I went looking for butterflies at VOA, I found a Henslow's Sparrow and a Sedge Wren instead (so I'd be happy with those too). I found neither, instead, I photographed my first dragonfly!

Halloween pennant (Celithemis eponina)
I love that face...big red eyes, freckles,
and what looks like a happy smile! ;-)

I know nothing about dragonflies. I didn't even know what they ate. After a quick Internet search I found they were carnivores and ate a lot of mosquitoes and other flying insects. I can't believe that as old as I am, I've never studied a dragonfly! They are GORGEOUS when viewed up close. Unfortunately, I still haven't gotten a macro lens, so I shot these with my 70-200mm with the 2x TC, catching a bit of detail, but not as much as a macro lens could do. The longer lens does capture cool photos by blurring parts of the wing and sharpening others, so I guess it's a good effect.

It was very breezy, but he (or she) clung to the stalk
with ease, letting those delicate-looking wings move
freely in the wind. I don't know if he was moving them
to adjust for the wind or if the breeze was simply
blowing through them like leaves on a tree.
(Either way, it was beautiful...and peaceful.)

There were five dragonflies I followed around for about 1.5 hours. Every one loved this plant and would return to these little stalks to ride out the breezes. At the time I didn't know what dragonflies ate, and I wondered what they liked about these plants scattered all over the meadow...I even wondered if they were eating the plant, but they didn't seem to be moving their mouths, so I assumed they were just resting. Soaking up the intense heat in the dry meadow, it was hard to imagine these beautiful creatures started life in the water. Their gorgeous wings were definitely made to shine in the sun...

Hang on tight little Halloween pennant!

Sun glistens off his wings producing
iridescent colors mixed with bits of gold.

I know I'll be heading to the bookstore tomorrow to find more info on dragonflies. A few are in my National Audubon Society Field Guide to Insects and Spiders, but I need more details!

Tom of The Ohio Nature Blog gave me the common name of Celithemis eponina, Halloween pennant, and recommended "Dragons and Damsels of NE Ohio" by Larry Rosche and Judy Semroc. He says it's one of the best dragonfly guides every published. I'll order it. It's available through the Cleveland Museum of Natural History. Thanks, Tom!