Friday, March 11, 2016

The "rare" one: caddisfly larva, Pseudostenophylax sparsus

This is the second time I've found this species of caddisfly larva.  The first was 6 or 7 years ago at the "Patricia Byrom Nature Preserve" in the Blue Ridge in a very small, very clean stream at high elevation.  But, if you look back to the entry of 3/12/14 you'll see that my friend in Sugar Hollow, has found them in a  tiny spring seep on her land.  Right at the base of this pipe.

This "pool" is 1-2' feet square, and below this you won't see flowing water, just wet leaves and mud.  But that's where this species lives.  Steven Beaty, "The Trichoptera of North Carolina," p. 84: "Occurs in seeps and temporary streams.  A late winter-early spring species.  Rare."  It will hatch as a "Dark brown summer sedge" -- Thomas Ames, Caddisflies, p. 250-251 -- but no trout to eat them in this little pool!

There is only one species of Pseudostenophylax that lives in this part of the country -- P. sparsus.  Pseudostenophylax species are described this way by Wiggins: " all species mesonotal setal areas are confluent through sa1 to sa2 to sa3, and there is a transverse band of setae between the metanotal sa2 sclerites.  Sclerotized parts of the head and thorax are uniform reddish or yellowish brown, broken only by muscle scars.  Abdominal gills are single.  Length of larva up to 16mm.  Larval cases are contructed mainly of small rock fragments, the exterior uniform in outline.  Length of larval case up to 19mm."  (Glenn B. Wiggins, "Larvae of the North American Caddisfly Genera (Trichoptera, 1977, p. 278.

This larva was exactly 16mm; the case, 17-18mm.  For the continuity of the mesonotal setae, this is the best I could do yesterday.

Easy to see the transverse band between the sa2 sclerites on the metanotum.

Not much question about the color of the head.

And yes, the abdominal gills are single.

Beaty adds that the "head and thorax [are] uniformly orangish to yellowish brown with pale muscle scars."  Those pale scars show up nicely on this photo.

A "rare" one -- Pseudostenophylax sparsus.

We also looked for nymphs and larvae in the small, pristine, stream that runs through her land, emptying below into the Moormans.  The leaf packs were LOADED with Peltoperlid (Roach-like stonefly) nymphs.  Other than that, we saw a number of spiny crawlers (probably Ephemerella invaria), and some nice Perlodid stoneflies -- Malirekus hastatis and Isoperla similis.  I took a few pics of the latter.

And on the rocks, as we would expect at this time of year, lots of flatheaded mayflies, Maccaffertium merririvulanum and Epeorus pleuralis, some of the latter already mature.

Good to get out at last.  The weather's improving -- very warm, actually -- so I'm looking forward to exploring the streams.

A note on the photos.  I'm not happy with the quality of the photos I'm posting.  For years, I've used the "iPhoto" software on my Macintosh to edit my photos: it's fast, efficient, and does a pretty good job.  But, Apple has replaced iPhoto with "Photos," for editing pictures.  I don't like it at all!  If you add the extension "intensify" to Photos, the results are better.  I also have "Photoshop Elements 9," which I like.  Unfortunately, "Photoshop" does not work with Apple's new system software (OS 10.11.3, El capitan), an issue that to date, neither Adobe nor Apple seems moved to address (!).  So, bear with me as I struggle to re-learn how to do this.  Maybe with practice...

And here the larva was just peeking out of its case.

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