Saturday, October 31, 2015

Goera time at Entry Run in Greene County

Too much rain has been a real problem so far this autumn.  Two weeks ago -- or was it three? -- we were hit with hurricane rainfall, over 8 inches.  Then this week we had another 4 inches on Wednesday.  The small mountain streams have cleared and started to drop, but the water was still fast and high today in Entry Run.

Still, I was quite sure I'd see some Goerids -- "weighted case-makers" -- and I did.  And I got some good photos of this one, a Goera fuscula, a species on which Beaty comments: "Mountains only.  Rare with less than 15 BAU (Biological Assessment Unit) records."  ("The Trichoptera of North Carolina," p. 87.)  While I often see G. calcarata in other small streams, this remains the only place that I've found fuscula.

G. fuscula has two distinguishing features. 1) "4 pairs of sclerites on metanotum," and 2) "sternal thoracic plates distinct."  (Beaty, p. 87)  In this case, one set of the sclerites -- those on the right side -- show up clearly in one of my photos.

The "sternal thoracic plates" require a microscope photo.

I saw a fair number of Goerids today, but they're very hard to pick up.  The cases sit on the tops and the sides of the rocks, but they're not really attached.  It's either a clean pick with the tweezers or they slip to the bottom.

Saw a number of flatheaded mayflies.  The one that I kept for photos was Maccaffertium merririvulanum.

There are two Macs that we typically see in these small mountain streams in the winter: M. merririvulanum and M. pudicum.  M. pudicum has a distinct ventral pattern; on merririvulanum nymphs it's the dorsal pattern that gives them away.  They have distinct "V- shaped" light areas on terga 5, 7 and 8.  The marking on 8 isn't real clear in this photo, but I assure you it's there.


Two other insects worth noting today.  One is a tiny, tiny Lepidostomatid.  The case was so tiny that at first, I wasn't sure what it was.  Still, the photos turned out alright.  (The case measured 3.5 mm; the larva was only 2!)

Like that first photo since you can see the eye on the larva, and you can see that the larva has started to convert its case from one made of sand grains into one made out of sections of leaves.

The other find was a shocker.  I found two, tiny Ephemerella subvaria spiny crawler mayflies!  I was stunned.  This is the first time I've found this species outside of the Rapidan River.   The bad news is that I didn't get any good photos.  Nonetheless...


It was good to get out today.  Sunny and cool, and I love the drive up South River valley.

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