Saturday, October 5, 2013

Hitching a ride -- the first spiny crawler (Ephemerella subvaria) of the season at the Rapidan River

It's the most colorful spiny crawler we see -- and at 8.5-9.5 mm -- one of the largest, and the only place that I've seen it is the Rapidan River up in Madison County: Ephemerella subvaria.  Beaty says that it's "collected summer through fall"..."mountains only"... and that it's "rare."  ("The Ephemeroptera of North Carolina," p. 28.)  I see them in fall through winter, and this is about as small as they get.

This one was collected last year on September 22:

This one on December 6:

And these -- male and female -- on March 29:

I'm glad that the season has started, and I look forward to seeing them more and more on future trips.

With this "tiny spiny" as the exception, the insects I saw today were much the same insects I saw on my last trip: Giant stoneflies, Common stoneflies, Humpless casemaker caddis, some flatheads, common netspinners, and fingernets.  Oh, and the occasional small minnow mayfly -- looked to be B. intercalaris.

1. Giant stonefly, Pteronarcys biloba.  Getting bigger and bigger.

2. Giant stonefly, Pteronarcys proteus.

And next to a recently molted E. vitreus flathead.

3. Common stonefly, Acroneuria abnormis.  (Note how different this is from the one that I found yesterday in the Rivanna.)

4. And one of the many Brachycentrids (humpless casemaker caddisflies) that I saw clinging to rocks.  Brachycentrus appalachia.

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