Thursday, March 12, 2015

Still waiting to hear: is it Isoperla kirchneri?

Finally.  The snow has melted and the temps have warmed up.  The bad news?  Most of our streams are too high to wade.  But not so the small streams in Sugar Hollow.

And I found one of the insects I was hoping to see: Perlodid stonefly, Isoperla kirchneri or Isoperla montana -- still no word on Kondatrieff's monograph that, we hope, will settle the matter.   But this is the only "type" of I. montana/kirchneri that I find in these little streams.  Note: no "bars" at the back of the head; wide pale area in the pronotum; and the pale spot in the ocellar triangle is almost completely enclosed.

But I still need to find a nymph that's fully mature to see if these distinctive traits are there right to the end.  For more on this issue, see the entry posted on 1/25 of this year.


The most common insect I found today was the pronggilled mayfly, Paraleptophlebia mollis.

There were lots and lots of them in the leafpacks.  Ought to be hatching in April or May.  We've talked about the species ID earlier this winter (1/18, 1/21).  To be sure of the ID, we have to look at the mandibles -- microscope work.  "Nymph uniformly brown in color; incisors of mandible strongly directed inward....Paraleptophlebia mollis."  (See p. 3.60 in Brigham, Brigham, and Gnilka, ed., Aquatic Insects and Oligochaetes of North and South Carolina.)  No question about it.


Not much else to get excited about -- but it sure was good to get back to a stream.

Other photos.

1. Leuctridae, genus Leuctra.  Common name, "Appalachian Needlefly"

2. Flatheaded mayfly, Maccaffertium pudicum.  (Commonly found with M. meririvulanum in these small, headwater streams.)

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