Thursday, November 15, 2012
A "pot pourri" of early winter insects: a trip to the Doyles
I went up to the Doyles River this morning, starting up at the top -- not far from where it exits the National Park -- and then coming downstream 5-6 miles to Blufton Road in Doylesville. I found pretty much what I'd expect to see at this time of year, but the insects at the two sites were really quite different.
At the upper site, where the stream is still pretty small -- and very rocky and clean -- I found 1) Giant stoneflies, lots of them, Pteronarcys proteus; 2) common stoneflies, Acroneuria abnormis and Acroneuria carolinensis; 3) tiny Chloroperlids (Green stoneflies), genus Sweltsa; 4) some fairly large flatheaded mayflies, Maccaffertium pudicum; and 5) some fingernet caddisfly larvae, genus Dolophilodes.
Interestingly, I did not see a single small or large winter stonefly at the upper site, and that's just about the only thing that I found in Doylesville!
1. Let me start with my photos from Doylesville, and with two of the large winter stoneflies I found. The first is the one in the picture at the top of the page, and here is the second. Both are Taeniopteryx burksi/maura.
I'm posting both photos because they were two different sizes, and you can see that the one at the top of the page is a bit more mature. The difference is in the spread of the wing pads. As the nymphs mature, the wing pads push further away from the body. I think that shows up in the photos below.
the smaller nymph:
2. A small winter stonefly, Allocapnia pygmaea?
3. And a Perlodid stonefly, Clioperla clio. This is one of many I saw at the Blufton site in Doylesville. It's a beautiful nymph -- but a ferocious predator: keep them in separate containers away from the rest of your insects.
1. And now from the upper Doyles site -- a Giant stonefly, Pteronarcys proteus, the same species we see in the small streams in Sugar Hollow.
2. One of the common stoneflies, Acroneuria carolinensis. On this species, you'll recall, that the anterior edges of the terga are light and posterior dark: just the reverse of A. abnormis.
3. Two M. pudicum flatheaded mayflies. There were a lot of them in the leaf packs.
4. And finally a fingernet caddisfly larva, genus Dolophilodes. The larvae in this genus are much lighter in color than those of the more common genus Chimarra.
No sign so far of the Isoperla Perlodid stoneflies, but maybe I'll see some tomorrow at the South River up in Greene county.
Below: a small winter stonefly that I found at Buck Mt. Creek last week -- Allocapnia mystica? Note how the wing pads are starting to darken.