Monday, May 2, 2016

Still the strangest mayfly nymph that I've ever seen: Ephemera guttalata

Steve Beaty talked me into using a kick net when I sample, and this morning I gave it a try.  Good fun.  I was able to collect insects from rocks, sticks and leaves, and the substrate all at the same time, and move through various spots on the stream before I looked to see what I had in the net.  Dumped everything into a white tray with water in it, and there were a variety of things moving around.   And since we were digging around in the substrate, we found this wonderful nymph that we only find there -- the "common burrower," Ephemera guttalata.

We've found them before -- for previous entries look back to 5/1/12 and 4/10/14.  In those entries, I've noted the features we need for genus and species ID.  But for a quick re-cap....

From Steven Beaty's "The Ephemeroptera of North Carolina," p. 44: "Genus diagnosis: Mandibular tusks divergent apically and curved upward in lateral view; frontal process of head distinctly bifurcate; small gills on abdominal segment 1 forked; abdominal gills held dorsally; ventral apex of of hind tibia produced into an acute point."

This last photo verifies the species ID as well: "E. guttalata -- nymphs up to 20 mm; abdomen generally lacking any color pattern."  He adds, "Collected mostly during spring and summer.  Mountains only.  Uncommon."

That's our nymph -- this nymph was 15 mm --  and I'm beginning to think this species is not all that "uncommon" in these small streams in Sugar Hollow.  Tolerance value: 0.0.

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