On my way to the stream this morning, I had already decided the title for today's entry, "Our Summer Small Minnow Mayflies," being sure I would find at least two of the species that we see in the summer -- Acentrella nadineae and Baetis intercalaris. Wrong -- though I did find two small minnow species, about which more in a moment. Then when I started picking up insects, I was finding the common stonefly, genus Perlesta, all over the place. So my title would be "Our May and June common stonefly -- genus Perlesta." And then I found this little beauty.
This is a Green stonefly, genus Alloperla -- the same Chloroperlid we found last week in a small stream in Sugar Hollow. But those nymphs were golden brown (see the photo in the entry for 5/18); this one was green, and I do mean "green"! If you look at the adult Alloperlas pictured at Bugguide.net (e.g., http://bugguide.net/node/view/402296), you'll see that they too are bright green in color.
I spent over an hour trying to get some good photos of this little insect, and I almost gave up. It never slowed down, it just kept dashing around the petri dish. And when it did pause, it would take off again before I had a chance to clearly focus! So I tried something new: I put the nymph in a tablespoon measuring spoon (my wife's suggestion, I hasten to add), which increased the odds in my favor. These are the best shots that I got.
I'll soon be posting an entry on Alloperla, with microscope photos showing the key features used in identification. In the meantime, I should note that Beaty says of this genus, "Mainly collected January through May in the Mountains. Uncommon." (Beaty, "The Plecoptera on North Carolina," p. 9)
And although I would like to ID our Alloperlas to the level of species, I don't think that's going to happen. Beaty advises to leave these at the level of genus, and although I've found a good article with illustrations and descriptions for eight, Eastern species, the detail needed to determine species ID is simply beyond me. (The article is Bill P. Stark & Boris C. Kondratieff, "Larvae of Eight Eastern Nearctic Alloperla Species (Plecoptera: Chloroperlidae), and it's on line at: http://www2.pms-lj.si/illiesia/papers/Illiesia07-04.pdf.)
Now on to our small minnow mayflies and the Perlestas. As I noted I did find two species of small minnow mayflies, but they were "spring" small minnows: Acentrella turbida and Plauditus dubius. Both species have been described in previous entries. I did get some good photos.
Plauditus dubius, female:
Plauditus dubius, male:
Acentrella turbida, female:
Remember that the tails on P. dubius are "banded" -- not so on A. turbida -- but A. turbida has the very broad thorax.
I'll give short shrift to what I thought might be my main topic: the common stonefly, genus Perlesta,
except to say that I never expected to see so many so close to being mature at this early date, and the one in the photos below is already ready to hatch. I'll pay more time on this insect in June -- we'll be seeing them in almost all of our streams -- and at that time, I'll pay more attention to genus and species ID.
One more insect that I was happy to find: a spiny crawler mayfly, genus Serratella. The "spring" spiny crawlers -- Ephemerella dorothea -- are virtually gone: while we saw that species in huge numbers, Serratella serratoides is a species we only see on occasion. Unfortunately, my live shots of this nymph did not turn out very well, so we'll have to settle for a microscope view.
A final look at our Alloperla Chloroperlid.