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.