Thursday, August 11, 2011
Waiting for Rain
When I start taking pictures of snails, you know things are getting desperate. We need rain -- lots of it. Our streams are drying up.
I went up to Sugar Hollow today to check on the tributaries to the Moormans River where I found so many wonderful stoneflies, mayflies, and caddisflies in the winter and spring. They've all been reduced to a trickle: smart bugs have moved under ground. I did find a few young Peltoperlids (Roach-like stoneflies), and the rocks in the still-water pools were covered with water penny larvae -- but that was it. Discouraging.
So I decided to look at the Moormans itself where it flows through Sugar Hollow, before it joins up with the Doyles in the town of White Hall. At least here there were a few riffles and some signs of aquatic life. I saw quite a few flatheaded mayflies -- they all looked like Maccaffertiums to me -- and I also found quite a few small minnow mayflies. Some of the small minnows were Baetis intercalaris, and this one, I "thought" was Acentrella nadineae.
But when I looked at this nymph through the microscope I didn't see any pigmentation in the gills, so at the moment I'm not really sure what it is (genus and species). Have to do more research on this one over the weekend.
Lots of fingernet caddisfly larvae and lots of netspinners too, both Hydropsyche and Cheumatopsyche.
The Hydropsyche larvae were both grey and olive green, as you can see in the pictures below.
The grey/brown larva spent a lot of time on its back in my tray -- which gave me a chance to see the frilly gills that covered its belly.
Finally, again, there were quite a few young common stoneflies, genus Acroneuria. As they did in the winter and spring, they were mostly crawling around in the leaf packs -- but they're also roaming around on the bottoms of rocks in the summer. Here's a real beauty.
Oh! Our snail! It's a Planorbid -- or, in Bob's terms, a "cinnamon bun" (!) But not a cinnamon bun that I'd like to eat. This is a "lunged" -- i.e. "tolerant" -- snail, and like most (not all) lunged snails, when looked at correctly, it opens on the left. Actual size? About the size of a button on a man's shirt. By the way, when the snail comes out and crawls around, the shell stands on end; it doesn't lie on its side. Pretty clear from the photo below.
This one kept oozing its way around my tray, and I had to push it over to get a good look at that case.
Here the case is turned the "wrong" way, so it appears to open on the right, but note the tentacles coming out.