Sunday, July 21, 2013

Is it a new species of Saddle-case maker? Glossosoma intermedium?

I didn't expect to see a whole lot this morning -- and I didn't.  Still, this one may be of interest.  It's a Saddle-case maker (Glossosomatid) that I found in one of the small mountain streams in Sugar Hollow.  I don't really expect to see Glossosomatids during the summer -- but I guess that I should.
Beaty notes -- on Glossosoma nigrior, the species that we normally see: "Relatively common during spring and late summer."  ("The Trichoptera of North Carolina," p. 66)

This larva, too, is a Glossosoma in terms of the genus -- but is it G. nigrior?  Beaty describes G. nigrior in the following way: "pronotum with small black spot above forecoxae; small sclerite in intersegmental fold between thorax and first abdominal segment laterally (separates out from G. intermedium).  Only confirmed species in NC."

I can easily see the G. nigrior markings on the Glossosomatids that I find in the spring.  Here's the spot on the pronotum.

And the sclerite in the intersegmental fold looks like this.

The problem is that I can't see that sclerite on the larva that I found this morning.

And I take it that that is the very thing that separates G. nigrior from G. intermedium.

More to come on this one.  Obviously, I've sent my photos to Beaty for confirmation since G. intermedium isn't found in his state.  But maybe there's something there that I'm missing.


Three other photos.

1. In the Moormans itself, I found this "Rolled-winged stonefly" (Leuctridae), genus Leuctra.  This is another taxon that I expect to see in the winter and spring.  Still, Beaty notes, "Widespread and very common during the spring and summer." (The Plecoptera of North Carolina," p. 2)  And I do recall finding mature nymphs in the autumn.  This is a small one: the wing pads are very hard to see.

2.  Also in the Moormans below the first bridge, and also unexpected, a small "Roach-like" stonefly (Peltoperlid).   I do expect to see little nymphs during the summer, I just don't expect to see them in a river the size of the Moormans, I normally find them in the small mountain streams.  Explanation?  Well, Beaty does say of Tallaperla (this genus), that it's "common in clean Mountain and Northern Inner Piedmont streams," ("Plecoptera," p. 12) so the distribution might be greater than I had concluded.  The other possibility is that these nymphs have been washed down into the Moormans by the flash floods of recent weeks.

3.  And -- hooray, hooray -- one we do expect to see -- the flatheaded mayfly, Epeorus vitreus.  They're still pretty common.

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