The "other" small winter stonefly that we see in at least one of our streams: Paracapnia angulata


No, no -- that's not a small winter stonefly, but it's a nice photo to start off this entry.  The Perlodid stonefly Malirekus hastatus for which see the entry of 1/29/12 (full discussion of the ID).  The backs of the wing pads reveal that this nymph still has a long way to go before becoming mature (it was only 11 mm), but it lacks nothing in color and pattern.  Got some nice photos.


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Now on to the big story.   As you know, almost all of the small winter stoneflies we see in our streams are genus Allocapnia, mostly, I think, A. pygmaea and A. mystica.  They're common at this time of year, with a genus tolerance value of 3.3.  But I had found some "non" Allocapnia Capniids, Paracapnia angulata, in a small headwater stream in Sugar Hollow back in January, 2012.  Today my friend and I went back to that stream, and sure enough we found them again!



Yes I know, they're not much to look at: they were only 5 mm.  But they're real beauties when they mature.  Below, the two that I found on 1/30/12.



Since I just discussed how Paracapnia differ from Allocapnia nymphs (11/22/13), I won't belabor the point.  But the key thing is the shape of the wing pads: "meso- and metathoracic wing pads rounded" (Peckarsky, Freshwater Macroinvertebrates, p. 66).  I.e.



The wing pads are real hard to see on the nymphs that I found since they're so small -- but you can see them in these microscope views.



The "hairy" body -- clearly visible in these microscope photos -- is characteristic of the species (Stewart and Stark, pp. 141-144).  So too, I take it, is the oddly shaped abdomen -- bulbous? -- which swells dramatically from front to back on very young nymphs (see Donald Chandler's photo at http://www.discoverlife.org/mp/20q?search=Paracapnia+angulata).

Very cool.  This is one of the things I was hoping that we'd see today.  It's so nice when you find what you're after.  North carolina, by the way, does not assign a tolerance value to P. angulata.  That means they have not found enough samples.  Beaty does comment however: "Nymphs are collected late fall through mid-winter in the Mountains only," and "Nymphs typically occur in small headwater streams, possibly in leaf packs."  (Beaty, "The Plecoptera of North Carolina," p. 1)  That's where they were: I found them in leaf packs in a small headwater stream in the mountains (elevation, ~1200 FASL).

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We saw a lot of Peltoperlids (Roach-like stoneflies) today and a lot of common stoneflies -- Eccoptura xanthenses -- both of which are common in these small headwater streams.  And we found some flatheaded mayflies, M. merririvulanum and M. pudicum.  But I only photographed two other insects.

1. A Leuctrid -- rolled-winged stonefly -- the first I've seen so far this year, and I saw more than one.  Notice the long, thin abdomen.



2. And a spectacular Ameletid mayfly -- probably Ameletus cryptostimulus, but it's a little too early to call that for sure.


Oh.  I did find an Allocapnia small winter stonefly as well.  So they are found together.  Think this one is A. mystica.