Last Saturday (12 June 2010) dawned gray and the forecast was for showers starting in the early afternoon. Cool (high 60’s) and cloudy is not a good combination for hunting odontates, but I figured why not! Thus, after a leisurely breakfast, I headed back to Carver’s Pond.
It is nearby so I could, by avoiding a longer drive, maximize my “field time” before it started raining. In addition, I had not been there in over a week (that pesky day job) and it was time to see what was new!
I spent an enjoyable few hours at the pond and was just heading back to the truck a bit after noon, when the rain got serious.
There were two real finds among the more common sights. The first was a male emerald swamp spreadwing (Lestes dryas viglax). [Identification updated on 23 June 2010… emerald and swamp spreadwings are very similar with swamp spreadwings being common and emeralds being “uncommon” according to “A Field Guide to the Dragonflies and Damselflies of Massachusetts” by Nikula, et al. (order here) which is my primary source for identiflying odontates.]
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Spreadwings are a small group of damselflies that generally perch obliquely on reeds and other stems emerging from the water. Additionally, when at rest, they hold their wings partially open unlike most damselflies who keep their wings tightly together when at rest.
The second find was a teneral female common pondhawk (Erythemis simplicicollis).
Odontates lay their eggs in water where they develop into larva. The larva overwinter (at least one year) in the water before emerging as adults. As the water temperature rises in the spring the larva emerge from the water and the adult emerges.
Each species has a characteristic temperature at which they emerge. The earliest odonates typically emerge in mid-May here in New England while the latest emerging species probably make their appearance around the end of June.
The newly emerged adult is characterized as “teneral”. In this state its body is very soft and its wings are not yet able to support flight. Teneral adults are usually found clinging to vegetation near the water and are very vulnerable to predation both by birds and by fish. As soon as they are able, teneral adults make a very weak initial flight to a more secure location to finish “drying out”.
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I noticed this individual after she had fully emerged. She was clinging to the grass stems and still had her rear end in the water and her wings were still folded back. (This is the only time you will see a dragonfly which wings held together.) Over the course of the five or ten minutes I watched her, she crawled up the stems as far as she could go and her wings became outstretched. You can see the very shiny wings typically of a newly emerged dragonfly; they only stay that way for a day or two. I decided that I had stressed her enough and moved away before she was ready to fly.
Here are the rest of the mornings photos:
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