Thursday, August 14, 2014

And it's another, unidentified, summer Lepidostomatid: Doyles River this time

I wasn't sure where to go to this morning, and I'm not terribly thrilled with my choice.  Still, I haven't looked in the Doyles for a long time, and I was expecting to see lots of small minnow mayflies.  I didn't.  I saw one, small, Baetis intercalaris.  Mostly, I saw tiny flatheaded mayflies and common netspinner larvae.

Just this one item of interest.  I spotted what looked to me like a case on the side of a rock and put it into my bowl hoping to see a caddis larva stick its head out.  Nothing.  It took about 20 minutes before I saw a little head and some legs.

Off to the car to get my camera and set up my gear.  Then I waited and waited and waited -- nothing ever came out of the case.  Still I took some photos, and as you can see in the photo at the top of the page, the larva did at least peek outside of its case.  A few more views.  (Look closely at the opening at the top.)

Of course when I put it into a vial for preservation it immediately emerged.


It was a very small larva -- about 6.5 mm.  But like the larva I found last week at the Rivanna, it was genus Lepidostoma.  Whatever the species, it clearly differs from those that we find in the winter.  I'd venture a guess that this larva was also distinct from the one I found at the Rivanna.

Remember that Beaty lists over 20 species of Lepidostoma in North Carolina, most of which remain undescribed.  A very distinctive feature of this particular larva -- dark head, pronotum, and mesonotum with very pronounced light colored muscle scars throughout.  I wish I could show that  to you with photos, but I dropped the tray in my lab, and there was no way to find such a small larva on a light colored speckled rug.  Oh joy.  Still, you can see the muscle scars on the head in the one photo I managed to take.

Very unusual.  I hope to do the Rapidan River tomorrow.  Sunday, it's off to Montana!

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