Thursday, March 2, 2017

Some nice pics of Ameletus sp.: a look at the Moormans

This morning, I went with my friend who lives in Sugar Hollow to the Moormans river, right down from her house.  We were curious to see if there were any Nemourids in there that we could check to the level of species.  There were.  But first things first.

One of the things that I found when I searched through the leafpacks was this Ameletid mayfly.   I think I've been identifying this one as A. cryptostimulus: I'm embarrassed to say I was wrong.  I re-read Beaty's description of A. cryptostimulus, looking for the dorsal features that he had listed -- just not there.  Two examples.  1) Note that the tarsi on our nymph are banded both apically and basally,

those on cryptostimulus have only an apical band.  2) Beaty describes the cryptostimulus cerci in the following way: "caudal filaments basally brown and with a dark brown medial band."  Those on our nymph are not basally brown.

In fact, these cerci match those of A. lineatus and A. ludens: "caudal filaments with dark median band interrupted every four segments by very narrow pale bands."  ("The Ephemeroptera of North Carolina," Version 4.0, p. 1)

Our nymph is, in fact, either lineatus or ludens.  Note Beaty's description of the terga of lineatus (ludens is much the same): "segments 1-8 with dark comma-like submedian markings."  Bingo.

So is it lineatus or ludens?  Well lineatus is bigger than ludens (12-14 mm, females  vs. 9.5? mm), and this was a pretty big nymph.  But there are other features -- especially on the sterna -- that have to be checked and I didn't keep the nymph!  Alas, next time.


We did find some Nemourids.

The "face" on this one looked a little bit different than those I was finding last week.  But, after doing the microscope work, I'd have to say it's the very same species.  Again, I think that's Prostoia similis, but I'm waiting to hear back from Beaty.

What we saw in pretty big numbers were the Isoperla stoneflies that provide the major hatch of "Yellow Sallies" in a lot of our streams -- Isoperla kirchneri grp. (probably I. montana).

Also showing up now, the spiny crawler mayfly, Ephemerella invaria.

These will hatch as P.E.D.'s (Pale Evening Duns) in April and May and June.  Oh, and if you look at the right rear of that nymph you'll see a little midge.  There were tons of them in the leafpacks.

So if you're fishing the fly fishing only section of the Moormans right now, I'd suggest using a Disco Midge dropper, and I'd start tying up some Yellow Sallies and P.E.D.'s for later on in the spring.

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