Friday, February 24, 2017

Mayflies, Stoneflies, Caddisflies: A real mix today at Buck Mt. Creek


It was the kind of morning I really enjoy:  sunny, warm (74º!), and the insects were plentiful, varied, and easy to find.  Let's look at some photos.

1. Large winter stonefly, Strophopteryx fasciata, pictures above and below.


There were a lot of them in the leaf packs, and some, as you can see, were fully mature.  In fact, I saw some adults flying around, and I think they were S. fasciata.  The one below landed on a rock where I was working.


I can't ID winter stonefly adults, and I found some small winter stoneflies that were also mature,


but my photo seems a good match for the S. fasciata picture that Donald Chandler has posted ( http://bugguide.net/node/view/179309).

2. Small minnow mayfly, Heterocloen amplum.


This is the only one that I saw which surprised me: they ought to be out in good numbers at this time of year.  But I see them right into April, and in April they hatch.

3. Another stonefly -- a Perlodid stonefly -- Helopicus subvarians.



It's a beauty, and it's fairly common in Buck Mt. Creek.

4.  Giant stonefly, Pteronarcys dorsata.


With a tolerance value of 2.4, it's the most tolerant of Giant stones.   I've seen it before in Buck Mt. Creek, and it's the species I also encounter at the Rivanna.  A good distinguishing feature for P. dorsata is the sharply produced corners on the pronotum.


5. Common netspinner, genus Cheumatopsyche.

Actually there were two in the same bunch of leaves.


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6.  But there was one thing I was really hoping to find and I did, and again I found two.  Nemouridae -- "Spring Stoneflies" or "Forestflies".



To ID these to genus and species, I need to do some microscope work.   Previous work on these nymphs has led me to two different ID's: Prostoia completa and Ostrocerca truncata.   Let me see what I arrive at this time, and I'll post my results in a separate entry tomorrow.

Great to see such variety, but it's what we get in the spring!

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