Friday, July 1, 2011

Home Water: The Rich Riffles of Buck Mt. Creek

Probably my favorite stream of all the streams that I sample.  I look for insects in four sets of riffles and never look very hard.  Of the four, the one in the photo above -- taken this morning -- is the one I like best because of the variety of insects that call this one home.  In a sample I did there last summer, we found 26 families of benthic macroinvertebrates represented in a total of around 200 bugs.  Not bad.

At the moment, I'm finding a whole lot of mayflies: lots of flatheaded mayflies (genus Maccaffertium), small minnow mayflies (two different genera), and a fair number of brushlegged mayflies -- this is a good brushlegged stream.  I also continue to find Perlesta common stoneflies in Buck Mt. Creek, and today I had a few young (1-year old?  2-years old?) common stoneflies that were genus Acroneuria.
Let's take a look.

This is a small minnow mayfly, genus Baetis.  I found 4-5 of them -- they were all very, very small.
The color is gray -- but that may change as they mature.  These have three tails and visible hind wing pads (though at the moment, they're not all that visible!)

The other small minnow I found is the same olive green and orange Baetid that I found last week at the Doyles River (check out the red/orange neck!).  I'm not sure of the genus: obviously, with the two tails, they (I found 6-7) are either Heterocloeon or Acentrella.  There is gray pigment in the gills, but I'm not sure that it's the "right" gray pigment for an ID of Heterocloeon.  Here is a mature specimen of the same species (note the dark wing pads)

Here is a microscope shot of the gills, and you can see the pigment much better when using this photo.

Still, the pigment is not exactly found in the "center" of the gills -- not at all like the pigment we saw in the Heterocloeon small minnow I found last week in the Moormans.   Those gills, you'll recall looked like this.

At the moment, I'd go with Acentrella for the genus ID of the small minnows that I found today.

I didn't take any pictures of the Maccaffertium flatheads since I already have quite a collection.  But, I couldn't resisted getting shots of the stoneflies.  Here they are: first the Perlesta and then the Acroneuria -- both Perlids (common stoneflies).

Below, the first set of riffles I come to as I make my way up at Buck Mt. Creek.

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