Dragonflies and Damselflies

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damselfly, possibly family Coenagrionidae

You might recall a recent post in which I wrote about two insect orders, Diptera (flies) and Hymenoptera (bees).  Today’s post is about the order Odonota, which is divided into two suborders: Anisoptera and Zygoptera.  Or less formally, dragonflies and damselflies (respectively).

Insects in this order share a few characteristics: long, narrow abdomens, two pair of slender, membraneous wings, and compound eyes that cover most of the head.

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look at the size of those eyes!

In dragonflies the rear wings are larger than the front wings; in damselflies, both sets of wings are about the same size.  The easiest way to tell them apart, though, is by observing the wings when the insect is resting.  Damselflies have hinges that allow them to fold the wings up over the body.  Dragonflies don’t, so their wings are spread out at rest.

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ebony jewelwing (Calopteryx maculata, Calopterygidae);
above, female; below, male

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It’s impossible to say for sure how many species or even how many families there are in the order Odonata. (“Impossible” in this context means every source I checked gave different numbers, and I don’t have hours to spend sifting through it all looking for something definitive, if definitive even exists.) Let’s just be vague and say there are about 5,000 species total.

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widow skimmer (Libellula luctosa, Libellulidae), I think; definitely a dragonfly

According to the Maryland Biodiversity Project, in this state there are 57 species of damselflies in three families, and 126 species of dragonflies in seven families.

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closeup of dragonfly wings

This is a subject I find fascinating, and I want to learn more, so expect another detailed post sometime in the future – like maybe in the winter when wildflower and gardening seasons are done.  For now, though, I just don’t have the time to teach myself all the finer points so that I can identify species and place them in families, so the captions are deliberately vague, with the exception of a few that experts have id’d for me.

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a damselfly

all photos taken in July 2014 or July 2015, along the Potomac River or C&O Canal

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