Friday, March 17, 2017

Some very nice photos today -- and a little surprise

The search is on for more Soyedina nymphs and some adults (see previous entry), something I'll explain in subsequent entries.  Suffice it to say that the nymph I noted last time is possibly one that's important, but we need more information.  Anyway, I didn't find any today, but I fared well nonetheless.

1. Above -- one of the better photos I've taken of the small minnow mayfly, Baetis tricaudatus.  I saw some small ones today but as you can see, this one was fully mature.  It remains the only small minnow mayfly I've seen in these tiny streams in Sugar Hollow, and with a TV of 1.5, it's where it belongs.  Some more photos.

2. And I found a couple of flatheaded mayflies, Maccaffertium pudicum, which also like these very small streams.

3. No surprises so far -- but this one was.

A pair of Isoperla, Perlodid stoneflies, and when I was taking my photos I was sure they were the very same species: Isoperla kirchneri group, possibly Isoperla kirchneri.   When I uploaded the photos, I saw that I was wrong.  Here they are again.

The first nymph in both sets is indeed I. kirchneri group, but the second is I. holochlora.  Can you see how they differ? Two things: 1) note the different abdominal patterns, and 2) look at the heads.  On I. kirchneri, the lateral stripes on the abdomen are straight, and the pale spot in the ocellar triangle is open to the rear.

But on I. holochlora, the inside edges of the lateral stripes are curved/scalloped and the pale spot on the head is completely enclosed.

I. kirchneri group nymphs are fairly common in these small mountain streams: not so with I. holochlora.  While I often find these nymphs at the Rapidan River, this is only the second time I've found them in Sugar Hollow.

Back to Sugar Hollow tomorrow to explore something new -- need to find more Soyedina.

Oh.   And a fairly mature Chloroperlid (Green Stonefly), genus Sweltsa.

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