Wednesday, April 16, 2014

The Green Stonefly Haploperla brevis -- and other treasures at the Whippoorwill Branch

After two inches of rain yesterday I didn't hold out much hope for finding good insects this morning -- but I was surprised.

In the photo at the top of the page, the Green Stonefly (Chloroperlid), Haploperla brevis.  Though Beaty says this genus and species is "relatively common" ("The Plecoptera of North Carolina," p. 9), this is only the second one that I've found.

Beaty describes Haploperla in the following way.  "Nymphs ~ 7 mm; cerci without dorsal or ventral intercalary hairs, setae at apex of cercal segments only; pronotum with sparse setae, longest and most numerous at anterior corners; long pronotal fringe hairs are at least 0.3 - 0.4 times the pronotal width; inner margin of hind wing pads subparallel to body axis; pronotum and tergites lightly setose; fore leg with sparse fringe of long setae on tibia; body light brown, nearly concolorous."  "H. brevis -- fits genus description."  Elsewhere, the NC tolerance value is given as 1.4.

1. Our nymph measured about 6 mm.

2. The lack of intercalary hairs on the cerci can be seen in the following photo.

3. And here is a view of the long setae on the corners of the pronotum.  I'd agree that the longest hair that we see is .3 - .4 times as long as the pronotal nymph.

4. The hind wing pads -- and the primary wing pads for that matter -- are indeed subparallel to the body, but we can only see that in a microscope view.   (Note: in many keys, this feature is the defining feature of this genus.)

5. And here we can see the "sparse fringe of long setae" on the fore tibia.

Haploperla brevis.  Made the whole trip worthwhile.


But I also found the freeliving caddisfly larva Rhyacophila carolina for the first time this season at the Whippoorwill Branch.

R. carolina is distinguished by its golden brown head, the lack of ventral teeth on the anal claw,

and the fact that the head is very wide at the rear -- in fact at that point it's almost as wide as it is long.

R. carolina is part of a group (the R. carolina group) that is found predominantly in the southeast.  The group includes R. fenestra/ledra, a species we also see in the summer.  This one.

TV for R. carolina is 0.4.

Another beauty this morning, a fairly mature common stonefly, Eccoptura xanthenses.  Note how the wing pads are long, and curved at the rear.  This one measured about 17 mm.


But the most common insect today -- the spiny crawler, E. dorothea.  Get ready to be overwhelmed if you're out there taking your samples.

For the species ID, you need a close view of the terga.  There are no tubercles (projections) on the rear edges of the terga on the nymphs of this species.


But this one was special -- Haploperla brevis.

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