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Dragonflies- Masters of the Air

 Whenever you get bored with your present hobby, I recommend you try learning to identify a few dragonflies.  They are common almost anywhere near fresh water and they come in a wide variety of colors and sizes.  While it is quite difficult to learn most of the dragonflies, or odonates as they are called, learning a few of the most common is easy.  Indeed this approach of studying only a few of the most common species first and learning them thoroughly is the best procedure for any new taxonomic group.   Once you know a few names you will find that the variety and complexity of dragonfly behavior is quite interesting.  This is even more surprising when you realize that dragonflies are quite primitive insects which have been on the planet for  more than 250 million  years in essentially the same basic form.  There were ancient dragonflies that were much larger, possibly due to higher levels of oxygen in the atmosphere.  

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The thing I find most amazing about dragonflies/odonates is their complex social and sexual behavior.  Typically the male is a different and brighter color than the female and immature males start by resembling females.  For example consider the common eastern pondhawk in which the male is a light blue with white cerci at the tip of the abdomen.  The female has a green thorax and a black and white banded abdomen.  Typically, bright colors in the male indicate that it is using coloration to reinforce territorial interactions with other males, and mate choice by the females.  Males attempt to maintain a tight control of females they have mated with to be certain that their sperm is used for fertilization.  Mating is complicated and occurs in a "wheel" formation whereby the male implants sperm into a forward receptacle on his abdomen from which the female receives it.  

 

It is quite interesting in my photo of a pair of mating common green darners in the wheel position that this particular female is colored much like the male, an unusual trait in this species.  But this circumstance, whereby females resemble males is not unusual, especially in damselflies and reveals complex interactions between the sexes.  Consider what the function might be for selection for female coloration which mimics the male?  If you even briefly watch the frenzied antics of odonates around a pond you might suppose that this might be a mechanism by which a female could escape the unwanted attention of males wanting to mate with her.  But it would certainly complicate the mating process.

 

One of my favorite dragonflies is the roseate skimmer in which the male is a bright purplish-pink while the female is brown.  So the male struts his stuff around the pond as "pretty in pink."   While this striking species is widespread throughout the southeastern US, an even brighter invader has arrived from Asia and colonized south Florida, the scarlet skimmer.  Here again the male is a brilliant scarlet and the female is brown.   There is little evidence at present that this beautiful but exotic species is posing an ecological problem since it favors disturbed habitats.

 

The scariest dragonfly for other dragonflies is certainly the famous "dragonhunter" which eats other odonates.  It is found in the eastern US down to central FL and is a beautiful yellow and black coloration with green eyes.  It is in the family of "clubtails" which have an enlarged tip of the abdomen.

 

So this brief introduction to five species of dragonflies should have given you a feeling for the great beauty and mystery of this group of primitive insects which so enliven the natural worlds of wetlands.  I have long ago given up fishing and instead spend much of my time around ponds observing these winged jewels of the air and "catching" them in photographs.  

 

Bill Dunson,  Englewood, FL, and Galax, VA 
wdunson@comcast.net 
http://www.galaxgazette.com/blogs                                                  http://lemonbayconservancy.org/dunson_archives.htm