Wednesday, July 11, 2012

A Few Dragonflies

The drought has desiccated the Blue Jay Barrens landscape, so it’s fortunate for me that you don’t need open water in order to attract dragonflies.  Many travel far from water in their pursuit of prey and can be found in just about any open field.  Unlike many other animals, dragonflies are arriving on schedule and in normal numbers.  This is a male Eastern Pondhawk, a species that normally sits on the ground or in low vegetation and attacks upward at passing insects.  My first glimpse of this species is usually when I scare it from its perch.  They normally don’t fly far and are easy to track to their new landing site.

In many species of dragonflies, males and females have distinctly different coloration and patterns.  The female Eastern Pondhawk is predominantly green with a black pattern on the abdomen.  That should make it easy to both identify and sex this species, but the males begin their adult lives looking just like the females.  A view from the side would show the female’s ovipositor, but I managed to miss that view.

The male Common Whitetail looks to have its abdomen covered in powdered sugar.  As a child, this was one of my favorite species.  The white coloration is quite brilliant and makes this an easy species to spot.

Males of other species also have the powdered abdomen, but none is quite as bright as the Whitetail.  The abdomen of this Widow Skimmer looks to have more of a blush of white.  Fortunately, wing patterns quickly distinguish the different species.

The female Widow Skimmer is another of those species that differs greatly from the male.  Immature males share the female’s appearance, but the females have darkened wing tips.  Personally, I don’t get too excited about distinguishing the immature males from females.  From a management standpoint, being able to identify the species is all that’s really necessary.

Looking superficially like the female Widow Skimmer is the female Spangled Skimmer.  The eye is first drawn to the abdomen with its central brown stripe flanked by bright yellow.  The thing that automatically sets it apart is the presence of white or yellow spots on the leading edge of the wing near the tip.  These patches of color are contained within a feature of the wing known as the stigma.  In most species, the stigma is solidly colored and appears as a dark rectangle.  In the Spangled Skimmer, the stigma is part light colored and part dark and is impossible to miss.  These are all common species that I see every year, but I always enjoy their presence.

3 comments:

  1. Great captures of these lovelies!

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  2. Great to see you have a good selection of Dragons around this season Steve. Those clean images certainly aid identification.

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  3. Thanks Pat.

    Hi Frank. A digital camera combined with one of the modern field guides is certainly a perfect tool to aid in dragonfly identification. Way back when I was in school, the tools were a net and a key that talked about wing venation and genitalia. That was quite a frustrating way to learn dragonflies.

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