Saturday, October 26, 2013

Goeridae -- the "Weighted-case Maker" -- at South River: Goera calcarata

(Please read the next entry.  This ID was wrong.  The larvae I found were G. fuscula.)

I've been waiting a long time to see this one -- but it's not really that photogenic!  This is the first Goerid (Weighted-case maker) I've seen, and I had to go to the South River (Greene County) to find it, that despite the fact that my friend has found them in a regular way in the small streams in Sugar Hollow.

At first glance, Goerids look a lot like Uenoids, but one of the ways in which they differ is in the design of the case.  "Case: Similar to that of Neophylax [Uenoid] but with a continuous row of larger ballast stones laterally, usually two."  (Beaty, "The Trichoptera of North Carolina," p. 87)  Uenoids typically have 3 stones on each side of the case, in some cases 4.

But what really sets the Goerid apart is the pronotum: "pronotum produced anterolaterally into wide, sharply pointed processes."  (Beaty, p. 87)  This is the best I could do in a live view.

They're easier to see in this microscope view as is the pointed nature of the head.

Another view  -- live view -- of the pronotal and mesonotal projections taken by my friend in Sugar Hollow.

According to Ames (Caddisflies, p. 232) the most common Weighted-case maker we see is Goera calcarata, and that's the species I found.   Beaty describes G. calcarata in the following way:

G. calcarata -- larvae 8-9 mm; 3 pairs of sclerites on metanotum; pronotum with central raised area the anterior margin with conspicuous spicules; sternal thoracic plates indistinct.  Common in the Mountains and Sandhills.  In North Carolina, G. calcarata is given a TV of 1.0.

Of the features noted by Beaty, the "3 pairs of sclerites on the metanotum" were very clear.

I could see the raised area on the prontum, but my photo is not very good.

I could not see any plates on the thorax.  But in the end, the metanotal sclerites will do to establish the identification since the other species that are found in NC (G. fuscula and G. stylata) both have 4 pairs of sclerites, not 3.   This larva was 11 mm.

Goera is known to fly fishermen as the "Little gray sedge," and according to Ames (p. 232) "They appear through June in the mid-South and into August in the Adirondacks and New England."

Nice to finally add this to my list.


Other photos:

1. Odontocerids (Strong-case makers) -- Psilotreta labida.  They were easy to spot on the rocks.

2. A pretty, small minnow mayfly -- Acentrella turbida.  Fully mature.

3. And -- finally -- the first small winter stoneflies of the new season.

Not much to look at at this stage of the game.

All Goerids were found in Entry Run, a tributary of South River.

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