Sunday, March 4, 2012

Slammed! By Lepidostomatids and Peltoperlids

This is the kind of silliness that I had to put up with this morning while taking my pictures: it was ridiculous!  And look at these clowns!

Still, you have to admit -- those are some of the prettiest Lepidostomatid cases you're ever going to see.

I used to sample with a local group that monitors our area streams, and when one or two taxa accounted for 1/2 to 3/4 of a 200 bug total, we said that we had been "slammed."   That usually meant something bad.  We might have run into a black fly colony -- there goes the score for that stream -- or in the spring it would probably be spiny crawlers.  If our dominant taxa had low tolerance values, being "slammed" would have a negative impact on the score for that visit.  But even with good tolerance values, insects that show up in numbers that overwhelm the sample will tear down the score because the "variety" that some metrics value just isn't there.

Well this morning I was slammed by Lepidostomatids and Peltoperlids, "Roach-like stoneflies," these little guys.

I'm talking hundreds of both of these taxa.  I've never seen that many Lepidostomatids or Peltoperlids in any one place at any one time.  I spent a lot of time in "search and rescue."  I.e. when I finished looking through leaves, the rock on which I had put the leaf pack would be covered with Lepidos and Peltos.  So, I'd pick and pick and pick to make sure that they all got back into the water!

But I can't say I mind getting slammed with insects like these -- it's the price you pay for going to very clean water in small mountain streams: Lepidostomatids (genus Lepidostoma) have a tolerance value of 1.0, and the tolerance value for Peltoperlids (genus Tallaperla) is 1.3.  This is perhaps the cleanest water I see in all of the streams that I visit.  Back in Sugar Hollow again (not much choice since rain has once again raised and colored the water in most of our streams), this time to the small tributary on the north side of the valley that I get to enjoy.  I did see other insects, by the way: as you would expect, all of them good: Chloroperlids (Green stoneflies), Eccoptura common stoneflies, tiny Leucrocuta flatheaded mayflies, and a few -- but only a few -- spiny crawlers (as opposed to what I just found on the "south" side of the valley).

I also found another Maccaffertium meririvulanum flatheaded mayfly, the flathead that only hangs out in "pristine," headwater streams, and I found a Leuctrid (rolledwinged stonefly).  I'll tie this up with some photos of those taxa -- and add a few more shots of our Lepidostomatids.

1. Maccaffertium meririvulanum.  Note that the wing pads are getting long now (as opposed to the one I found in this stream on 12/11/11), and remember the defining characteristic: pale "V's" on abdominal segments 5, and 7-8 or 7-9 (this one also has one on segment 4).

2. Some good close-ups of a young "Rolledwinged stonefly" (Leuctridae), genus Leuctra.

3. And a couple more looks at our Lepidostomatids.

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