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.

A new "humpless" case-maker, one that's "imperiled" in the state of Virginia: Adicrophleps hitchcocki

First of all, let me be clear that I did not find this insect, and I did not take these photos.  This little case-maker was found yesterday by my friend who lives in Sugar Hollow and explores, in a regular way, those little headwater streams that empty into the Moormans.  It was found in a special stream that flows down the mountain by the side of her home, one that I've been to a number of times.  This one.

The species identification was suggested to us by Steven Beaty.  However, he cautioned that certain anatomical features were not revealed by her photos so he couldn't be totally sure of the ID.  In no way is he responsible for any claims that I make in this entry.

That being said, I'm fairly certain that this caddisfly larva is the "humpless case-maker" Adicrophleps hitchcocki, a species that NatureServe lists as "imperiled" in the state of Virginia.  (See: http://eol.org/data_objects/18606087.)  Its existence is also attested in Connecticut, Pennsylvania, West Virginia, and Maryland.

I would base our ID on remarks made by Wiggins in Larvae of the North American Caddisfly Genera (Trichoptera), University of Toronto Press, 1977, pp. 52-53.  Four critical points.

1. Case description.  "Larval cases in Adicrophleps are four-sided, tapered, and constructed of pieces of moss arranged transversely; trailing ends frequently left attached to the moss pieces give the case a furry appearance."  (Wiggins, p. 52)  That matches our case exactly.

2. Habitat.  "Larvae were collected in several cold, rapid streams from 1 to 10 m wide from aquatic moss (Scapania) in riffle areas at depths not exceeding 30 cm;  they were exceedingly difficult to find in the moss."  (Wiggins, p. 52)   My friend is a moss specialist, and that is exactly where she found this case.  And remember, this is the stream in which it was found.

 Right width and depth and plenty of moss covered rocks.

3. Description of the head.  "The head of A. hitchcocki has light-coloured muscle scars and bears a pair of longitudinal ridges along the anterolateral margin of the frontoclypeal apotome."  (Wiggins, p. 52)  Right on the money.

4. Mesonotal sclerites.  In his key to Brachycentrids, Wiggins defines Adicrophleps in the following way:  "Each half of mesonotum subdivided into three separate sclerites."  If you look closely at our larva, you can see the three on the right side.

One other thing. Wiggins' illustrations on p. 53 show that this species has very long setae on the anterior and posterior edges of the mesonotum and on the anterior edge of the pronotum.  No question about it.

Other anatomical features that we could look for: 1) larvae have a short prosternal horn, and 2) according to Wiggins, "abdominal gills are lacking and the lateral fringe is absent."  To see those features, and thus be totally sure of our ID, we would have to preserve a larva.  We prefer not to do that when the species is "imperiled."  But, I see no reason to doubt this identification.

Very exciting!  I'll add this to our EPT list.  See postings for 9/8/12 and 10/8/12.

Goera country: "weighted case-makers" in Entry Run and the first spiny crawler of the season

I went up to Greene County this morning to see if I could find another Goera: obviously I did.   Like those that I found here on 10/26, this one was Goera fuscula.  "G. fuscula -- larvae 9-11 mm; 4 -pairs of sclerites on metanotum; sternal thoracic plates distinct; face with central area smooth; posterior carina sharp and high." (Beaty, "The Trichoptera of North Carolina," p. 87)

 This larva was 11 mm, and the "face" surrounded by the carina showed up pretty well in one of my photos.

The Goeras I'm finding are all in small head-water streams in the mountains, streams like Entry Run, which in the photo below flows into South River.  Goera country.

Keep in mind that Beaty regards G. fuscula as "rare," so it's always a pleasure to see it.

My other findings this morning were pretty much what we're expecting to see at this time of year: large winter stoneflies (Taeniopteryx burksi/maura); Chloroperlids (Green stoneflies); pronggilled mayflies (genus Paraleptophlebia -- that's one on the rear of the case in the photos above); Giant stoneflies (P. proteus); Common stoneflies (A. abnormis and A. carolinensis); and some flatheaded mayflies, including some tiny Epeorus pleuralis.   But there was a surprise ...

a spiny crawler nymph, number one of the new season!  On examination, this turned out to be Ephemerella invaria, the species with "paired submedian tubercles on segments 3-8" (Beaty, "The Ephemeroptera of North Carolina," p. 27).   E. invaria nymphs commonly have a "pale transverse stripe between [the] eyes" (Beaty) which I think you can see if you look closely at the photos below.

They're not very colorful at this stage of the game -- but that will change as we move into late winter.
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Other photos:

1. Giant stonefly, Pteronarcys proteus.  Estimated size, 30-40 mm.  Big!

2. Flatheaded mayfly, Maccaffertium merririvulanum, another insect that we only find in head-water streams.

3. And a miserable, miserable common stonefly, Acroneuria carolinensis.  I don't want to tell you how long I waited for this critter to stop moving around in the tray!  This is the best I could do.

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Driving up South River valley on my way to Entry Run.  Very pleasant day.