Showing posts with label Dragonfly wings. Show all posts
Showing posts with label Dragonfly wings. Show all posts

Wednesday, August 31, 2011

A Female Widow Skimmer dragonfly in the high meadow...

Sunday, Rick and I decided to check out the high meadow at Voice of America (VOA) park. I wanted to see if the Bobolinks were still around (I didn't see any...) and if I could photograph a few dragonflies. We also chose VOA because it's a grass field, and grass offers a lot more cushion and therefore less impact on an ankle than cement paths or uneven terrains. I have a reconstructed ankle from an injury back in 1985, and I've developed arthritis in that foot. Every now and then, I do something stupid (like running through a very large parking lot) and severely inflame it. Yeah! Then I have to be careful for a couple of weeks...so grass it was!

Dragonflies were everywhere in the meadow, especially Widow Skimmers, and I was glad when this female flew into camera range and posed right away, resting on a dead stalk. She stayed around for several minutes, flying away for a second or so and then coming right back. Sometimes when she left she nabbed an insect to eat, but mostly she was simply disturbed by the sound of the shutter clicking...

Female Widow Skimmer (Libellula luctuosa) Dragonfly

Female and juvenile male Widow Skimmer dragonflies have dark brown patches at the base of their wings close to their bodies. Adult males do too, but they also have powdery white patches on their wings. Unfortunately a male didn't fly into view, so I don't had a photo of one (click here for a photo on "BugGuide").

Someone once told me Widow Skimmers were named after the wide dark brown/black patches on their wings. These patches were the color of mourning clothes and therefore were called "widow patches." Maybe that's true. I did find a similar reference on the "Living with Insects Blog," here, but I also read that "widow" refers to the fact that male Widow Skimmers leave the females after they lay their eggs (leaving them widows), while males of most other dragonfly species stay with the females (source: Loudon Wildlife Conservancy). That makes sense too, until I read in my dragonfly field guide, "Dragonflies and Damselflies of Northeast Ohio," by Rosche, Semroc, and Gilbert (pg 153), that "males perform territorial battles and hover guard their ovipositing mates tenaciously," which is completely the opposite. So I don't know what to think. Maybe the name "widow" is derived from the Latin "luctuosa," which means "sorrowful" (Latin source: Living With Insects Blog). Whichever the case, thinking of the dark brown patches at the base of the wings as "widow patches" always made it easy for me to remember the name of this dragonfly a long time ago...so I'll stick with that!

Female Widow Skimmers have a yellow stripe running dorsally on their thorax. At the abdomen it splits into two stripes that extend the length of the abdomen. Juvenile males have the same marking.


You can tell this Widow Skimmer is a female and not a juvenile male because of her smooth abdomen. A reference on "The Butterfly Digest" blog, here, explains how to tell the difference between a female and a juvenile male Widow Skimmer dragonfly (with links to BugGuide of photos of the hamule).

...glad you dropped by Widow Skimmer. it was fun photographing you!

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! :-)