Thursday, March 6, 2014

Can we say goodbye to winter? A mature S. fasciata large winter stonefly at the Doyles

Sorry.  This is not the S. fasciata large winter, but it has to come first.  A beautiful Perlodid stonefly Helopicus subvarians.  It was about the same size as the one I found last week at Buck Mt. Creek: 17 mm (about 3/4 inch).  I do believe that H. subvarians is the largest Perlodid stonefly I see.

Gorgeous!  This is still immature; the wing pads will lengthen, spread out from the body and turn black.  I normally find nymphs that are fully mature in late March and April.  The photo below was taken on 4/8/12.


I don't know anyone in Virginia who does not want to wish this winter "Goodbye."   Cold, cloudy, rain and snow.  But there are signs that things are starting to change, both outside and in the insects we see in our streams.  The winter stoneflies -- the small winter stonefly Allocapnia pygmaea, and the large winter stoneflies, Taeniopteryx burksi/maura, Taenionema atlanticum, and Strophopteryx fasciata -- are just about gone.  The small winters are the first to go, then T. burksi/maura followed by Taenionema and Strophopteryx.  Here's the S. fasciata that I found today.

Fully mature.  But from earlier in the winter...

Small winter, Allocapnia pygmaea: 12/11/13

Large winter, Taeniopteryx burksi/maura: 1/19/14

And in Sugar Hollow last week (3/1), I found a Taenionema atlanticum nymph that looked exactly like this (though this photo was taken on 2/2/12).  The Malirekus hastatus nymph ate it when I wasn't looking!

If the winter stoneflies take winter with them, I can't say I'm sorry to see them go!

But there were also clear signs of spring at the Doyles River this morning.

1. Small minnow mayfly, Heterocloeon amplum, one that's starting to show its colors (note the orange color of terga 4 and 5).

This one was clearly a male -- note the large eyes.  Also worth noting -- and I've seen this before -- the eyes at this point appear to be "double" as they transition to red.

2. A "tiny" spiny crawler, Ephemerella invaria, the one with the tubercles on abdominal segments 3-8.  (Too small to see in this photo; it requires magnification.)

3. And a small Isoperla montana/sp., the Perlodid stonefly that we saw in great numbers at the Rapidan River just a few weeks ago.


But nothing could compare to this beauty.

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