Tuesday, March 22, 2011

The "Hidden Stream": Second Visit

I first looked at this stream on March 4th (see the entry on "Hidden Streams"), so this was my second trip.   For beauty, this stream has no match: crystal clear water, waterfalls, glides and pools, and moss covered boulders and rocks.  I could easily spend many a day exploring this wonderful branch of the Moormans.   And the insects?  Diverse and abundant, and only the best.  Can you blame them for wanting to live in this place?!

Today I moved downstream from the water I explored the first time.  And I found different insects -- though I think that has more to do with the changing seasons than the change in location.  Thus, last time I found stoneflies from 8 different families; today I only had 5.  I still didn't find any Leuctrids (Rolledwinged Stoneflies) -- even though I'm finding them on the other side of the valley.  Also missing this time -- large and small winter stoneflies and Nemourids (genus Nemoura).   There's a good chance that these three families are gone, hatched;  I certainly did see large winter adults alongside the stream and in the air.

So what did I find?  Giant stoneflies -- lots of them!  There were 6 in one leaf pack alone.  I started brushing them back into the water as soon as I saw them.  And I saw "large" Giants and "little" Giants.
In this photo, two of them actually snuggled together inside my tray.  (Note the Green stonefly to the left of the "small" Giant -- and the contrast in wingpad development on the two Giants.)

I also found a fair number of common stones, and like last time, they were mostly Eccoptura stones; only one was genus Acroneuria.  I did get a nice photo of one of the Eccoptura nymphs.

Again, there were "Roach-like" stoneflies running around -- but I gave them a break from my lens.  And again, there were quite a few Chloroperlids (Green Stoneflies), genus Sweltsa.  They were considerably bigger than those I saw on my first visit.

I also saw a few Perlodid stoneflies, all genus Isoperla, and they were larger here than those I've been finding on other streams in the last couple of weeks.  The characteristic "brown stripes on yellow background" that we find on the abdomens of these insects were actually starting to show -- though I'm not sure you can see that in this live shot.

Mayflies?  I found a number of Pronggilleds and a few Ameletids and two genera of flatheaded mayflies: Leucrocuta and Epeorus.  Leucrocutas have a small body with a very large head, which is pretty clear in this photo.

I took a number of photos of one of the Epeorus mayfies -- they were abundant -- but my favorite is one in which it's side-by-side with a young spiny crawler.

Speaking of "spiny crawlers" -- I don't think I found them last time; this time there were a lot of them here.  Most were genus Ephemerella (including the one in the photo above), but I did find my very first spiny crawler, genus Eurylophella!  Exciting!  Unfortunately, he was crawling around in a mud filled leaf pack and refused to bathe for his guest.  So, it's not the prettiest nymph that you're going to see.

Remember from the entry on 2/17 that this genus is special: it has gills on abdominal segments 4-7, but the gill on segment 4 is large and operculate and covers the rest.  We can see that best in this microscope photo I took when I got home.

The other "first" that I had today was finding a beautiful "Northern Case-maker" caddis (Limnephilidae), genus Pycnopsyche, which makes the prettiest case of which I know.  It's a three-sided case made out of nicely clipped pieces of leaves.

Quite a feat of engineering!  I waited and waited for the larva to stick its head out -- and it finally did.

On caddisflies -- I found a lot of common netspinners, genus Diplectrona (TV of "2"), and I found several Freeliving caddisflies: this time, they were all "green," just like they're pictured in Voshell (Freshwater Invertebrates, p. 164, plate 77).   Let me finish this entry with two nice pictures of one of those.

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