Thursday, August 27, 2009

LOOK FOR: Dragonflies

Why do we love dragonflies so? The iridescent grace of finely veined wings, the constant motion over a sunny pond, the bright colors and striking patterns...

Plus the eating of mosquitoes. As adults, dragonflies use their legs as a basket to catch other flying insects, like mosquitoes -- thus their nickname, "mosquito hawks."

But they don't just eat mosquitoes in the air. Both dragonflies and mosquitoes lay their eggs in water. And dragonfly nymphs are voracious eaters, with mosquito larvae on their menu. Some dragonfly nymphs also eat much larger prey, like small fish, tadpoles, and other aquatic critters.

When it's ready, a dragonfly nymph crawls out of the water, splits its back open, and emerges as an adult. Fast forward to 2:20 in this video to see the process, greatly sped up:

There have been at least 120 species of dragonfly recorded in DC and Maryland. Here are a few you might have noticed:

Common Green Darner
Anax junius
Halloween pennant
Celithemis eponina
Common Pondhawk
Erythemis simplicicollis
Blue Dasher
Pachydiplax longipennis
Autumn Meadowhawk
Sympetrum vicinum
Common Whitetail
Libellula lydia

In the wild: Look for a sunny pond or stream. You may notice that you see different species depending on the size of the body of water, whether it is moving or still water, and how shaded or sunny it is.

In your yard:
You're much more likely to have dragonflies if you have water. This is our third summer having a pond in our backyard, and we have started to see dragonflies relatively regularly. Which makes me a very happy camper.

What's your favorite spot for watching dragonflies? Do you have a favorite species that I left out? Leave us a comment!

Photo credits: Top photo by the Natural Capital; Common green darner by mean and pinchy; Halloween pennant by afagen ; Common pondhawk by meanlouise; Blue dasher by Dope on the Slope; Autumn Meadowhawk by jerryoldenettel ; Common Whitetail by afagen. Click on any picture for a larger version of the photo on flickr.


WashingtonGardener said...

Had no idea there were so many kinds here -- I've been grilling insect folks for years now on why somehow hasn;t written a dragonfly book forthe Mid-Atlantic or just one on "draginfly gardening" -- of more interest to me than butterflies actually.
My fave DF viewing spots are my backyard pond and Kenilworth Aquatic Gardens.

Anderkoo said...

A dragonfly flew into our apartment a few weeks ago, landed on the sprinkler head, and slept there all night. By morning it was gone. Too bad they aren't nocturnal; we could have used some mosquito-scraping that week.

I was disappointed that some Facebook friends responded negatively to my delight at this occurrence. Seems dragonflies suffer a lot of prejudice, maybe from their days of being called "darning needles" and the superstition that they sew up your mouth while you're sleeping?

A friend in NY reports that there have been swarms of dragonflies there, many more than normal. Could there be a bumper crop this year because of the rain, meaning more mosquitoes?

Anderkoo said...

Here's the story in the Times, btw:

Elizabeth @ The Natural Capital said...

Thanks for the link, Anderkoo, very interesting article! I am fascinated that some people were creeped out by a dragonfly in your apartment. I've never met someone who admitted to not liking them, but I guess I haven't asked every one of my friends...

As for field guides, I have a friend who uses
"Dragonflies through Binoculars", but it's not specific to the Mid-Atlantic.

Me, I've always wanted to write a children's book about dragonflies. But I'm sure there are already many out there.

dcpatton said...

I am also interested in a good guide to Dragonflies and Damselflies. Any suggestions? Also, don't you see an increase in mosquitoes from that pond?

Elizabeth @ the Natural Capital said...

We don't have any more mosquitoes than our neighbors -- in addition to fish and dragonfly larvae for control, we put "mosquito dunks" (which contain BT, a bacteria that kills mosquito larvae but not most other aquatic critters) in the pond.

I'm going to have to pick up a copy of "Dragonflies through Binoculars" and let y'all know what I think!

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