Sunday, June 19, 2011

Looking for Bugs in the Rain: Buck Mt. Creek on Father's Day

Well, my daughter lives in Portland, Oregon, so obviously she wasn't going to call until 1:00 or 2:00 PM.  So, I decided to go to Buck Mt. Creek to look for small minnow mayflies.

It was stupid.  It was overcast -- dark sky -- but I thought it might clear.  It didn't; it rained!  But by then I had collected 20+ interesting nymphs -- so what to do?  I decided to drive back home with my bowl and take the photos back there.  Mistake.  I made a sharp turn on the way back, the bowl overturned, and out came all of my insects!  I quickly stopped at a store, bought a bottle of water, picked my bugs up from the floor of the car and made it back home with some things still intact!  Ah joy.

But, I got some good photos, including this beautiful, fully mature, Perlesta common stonefly (Perlid).  I still found some young nymphs, but I found two of these beauties in a single leaf pack.    Another look.

Actually, this is just about the only stonefly I'm finding anywhere at the moment.  The Perlodids seem to be gone -- except for some Isoperla holochloras in the high elevation tributaries to the Moormans River and up at the Rapidan.

I also saw -- but collected only a few -- a lot of flatheaded mayflies.  Three genera: Epeorus (vitreus), Maccaffertium, and Leucrocuta.  Somehow, one of the Leucrocuta nymphs I collected made it all the way home intact -- a small miracle.

The small size and large head, and the way it sped around the rock gave it away.  But remember, the key thing is that gills 1-6 have fibrilliform between the gill and the body; gill 7 does not.  I tried to get microscope photos of gills 6 and 7 this time to prove the point.  Here they are:

Gill 6:

Gill 7:

No fibrilliform.

My goal in going out today was to find some more small minnow mayflies since I want to establish the "hatch" pattern in this part of the state.  Which genus/genera do we find in the winter?  How about the summer and fall?  So far, I've found Acentrella nymphs in this stream -- all of them very small -- but I've also found, recently, a three-tailed Baetis nymph.  You may recall this recent photo.

I only found 1 nymph today -- again a three-tailed Baetis.  He did not survive the trip to my home in very good shape: still, here is a photo.

Once we see the three tails, we have to look at the "labial palps": are they "rounded" or "truncate"?  They're rounded.

And the last test -- does it have metathoracic wing pads?  Yes it does: this one is very clear.

I hope by the end of the summer I can determine the "species" as well as the genus of this "three-tailer".
I imagine these will hatch in late August or September.  But more on that later on.

Almost forgot.  I also saw a fair number of Brushlegged mayflies today, and they're already pretty big.
They're very difficult to pick up with tweezers, but I did manage to grab this one.

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