Saturday, February 22, 2014

Back to the streams! The northern case-maker Pycnopsyche gentilis

It's been a long two weeks: 18 inches of snow, 1-2 inches of rain, and now warmer temps = streams that are flowing out of their banks.  Even the small streams in Sugar Hollow are still high and fast.  But I was determined to see some insects this morning.

And this is one of the taxa I was hoping to find: the first Limnephilid (northern case-maker) of the season, Pycnopsyche gentilis.  This is the caddis that -- in its early instars at least -- makes a three-sided case of neatly cut sections of leaves.  Like the Uenoids we're seeing right now, these larvae will pupate through the summer and emerge in the fall as "Great brown autumn sedges" (Thomas Ames, Caddisflies, pp. 252-257).

I've keyed out this species in an earlier entry (9/14/12), to which I urge you to turn.  However, one of the defining features for species ID is the lack of a dorsal hump on abdominal segment one, which we can clearly see in this photo.

This is a larva we'll see right into April, but by then many will have built new cases of gravel.


Uenoids.   I only picked up a couple, both of them, to my surprise, were Neophylax mitchelli: clavate ventral gills and a prominent frontoclypeal tubercle, one that points to the rear of the head.
Like most of the Uenoids I find in this stream, both made beautifully colorful cases.




Mayflies.  I saw a number of Maccaffertium flatheads, some pronggilled mayflies, and one tiny spiny crawler (Ephemerella).  But the bottoms of rocks were covered with Epeorus pleuralis flatheads -- as they commonly are at this time of year.


Stoneflies.  Lots and lots of the large winter stonefly Taenionema atlanticum, and I saw a lot of the adults flying around.  My photos did not turn out as well as I wished: somehow antennae got broken.


And this is where I was wading -- very carefully, I might add!

Back out on Monday.  I might risk a trip to the Rapidan River.

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