Thursday, January 3, 2013
Winter Insects at the Lynch River
After looking for insects for just a short while this morning, I wondered why my toes and fingers were freezing. But when I started my car, I saw that it was only 32º at the Lynch River. Still, there was enough sunshine for me to take photos, so I had to get out and explore.
I didn't find anything "stunning" today, but I did see a good collection of the insects I expect to see in a lot of our streams at this time of the year. Perlodid stoneflies: Helopicus subvarians, Clioperla clio, and Diploperla duplicata; flatheaded mayflies; common netspinners, especially Cheumatopsychids; Glossosomatids (saddle-case makers) and Uenoids; midges; and, unfortunately, large numbers of black flies -- "colonies" of them in fact. I also saw one of the things I was hoping to see -- the small minnow mayfly Heterocloeon amplum, the one in the photo at the top of the page.
H. amplum is the largest species of small minnow mayfly (Baetidae) that I see during the year, and it's one that I normally see in January through March; sometimes into the beginning of April. Mature H. amplum nymphs are 7-9 mm long: the one in this photo was 6 mm, not yet fully grown. Still, a lot of the features we use for this species ID are easy to see in this photo: 1) there are two cerci/caudal filaments/tails; 2) the tarsi are "dilated apically" (i.e. they're wider); 3) there is a wide, pale medial band on the tarsi; and 4) there are paired dots on the tergites.
The streams where I go to find this one? The Doyles, Buck Mt. Creek, and the Lynch.
1. Common netspinner, genus Cheumatopsyche. I saw a lot of them, all of them bright green in color. I'm increasingly convinced that this is our dominant winter netspinner.
2. Common netspinner, Ceratopsyche alhedra. I found this larva on the same rock as the Cheumatopsyche just pictured. There was one C. alhedra on the rock, six Cheumatopsyches. The head on this species is black with no visible pattern.
And here's a photo of the two netspinners side-by-side in my tray.
3. The Perlodid stonefly, Helopicus subvarians, one that I also see in the Doyles River and Buck Mt. Creek.
4. The Perlodid stonefly, Diploperla duplicata. I always see a lot of these in this stream.
5. And Uenoids, Uenoids, Uenoids! They're on the tops of the rocks, the sides of the rocks, and the bottoms of rocks, and the light-colored cases are easy to see. Here are photos of three different larvae.
As you know all of our Uenoids are genus Neophylax. But I'm not having a whole lot of luck getting the ID down to the level of species. The species descriptions given in Beaty ("The Trichoptera of North Carolina," pp. 86-87) do not provide sufficient detail for certain ID while the other source that I use (R.N. Vineyard, G.B. Wiggins, H.E. Frania, and P.W. Schefter, The Caddisfly Genus Neophylax [ROM Contributions in Scince, 2]) goes into too much detail. But, this is something I will continue to work on.