Friday, November 16, 2012

"Shock and Awe" at South River this morning

I was indeed "shocked" by two of the taxa I found at South River this morning, and I was in awe of the variety and numbers of insects I found in this healthy Greene county stream.

One of the shockers -- I found 3-4 Lepidostomatid caddisfly larvae including the one in the photo at the top of the page.  This is the case-maker we only see in small mountain streams, and we see them in large numbers, in some of those streams, during the winter.   It's only November...but they're already here.  Some Lepidostomatids, like the one in this photo, initially build their cases out of grains of sand, then switch over to a four-sided case made of neatly cut pieces of leaves.  The genus is Lepidostoma, and the TV is 1.0.

More photos:

1. another view of the larva in the photo at the top of the page

2. and a second case that appeared to be empty...

but wasn't!  Pretty cool.

And for shocker number two -- several tiny flatheaded maflies -- Epeorus pleuralis!

This one I did not even see until I started taking my pictures.

I'll see a lot of these in this stream in the winter and spring: but again, it's only November, and I never thought that I see them this early.   This is another insect that lives in small, quality, mountain streams with a tolerance value of 1.5.  Fishermen know it as the Quill Gordon.  You'll find these on the bottoms of rocks.  And in April, they'll look more like this:


And now for the insects I expected to see.  Without any question, the dominant insects in my findings today were the pronggilled mayfly, genus Paraleptophlebia and the small winter stonefly, genus Allocapnia.  The leaf packs were loaded with both of these nymphs, and I got some very nice photos.

Pronggilled mayfly, Paraleptophlebia

Small winter stoneflies, genus Allocapnia

1. Allocapnia pygmaea?



female and male together (the males are smaller than the females):

(Question:  Do the female wing pads lighten in color as they mature and the male wing pads get darker?)

And for the rest...

1. Chloroperlid stonefly, genus Sweltsa.  I found quite a few, all still very small.

2. A couple of small, free-living caddisfly larvae -- Rhyacophila fuscula.  You can see the "topless H" pattern on the head of the second.

 3. Giant stonefly, Pteronarcys proteus, "the Giant who lives in our small mountain streams."

4. A Perlodid stonefly, a very young Isoperla similis.

5. And still hanging around -- which is also a little bit "shocking" -- a Strong case-maker caddis, genus Psilotreta.


Below, the South River in the first photo: in the second, a tributary that flows into the South slightly downstream from where the first picture was taken.  At the moment, both streams are loaded with insects.

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