A tough day at the Doyles: still, no winter stoneflies

Now the sun is shining, but I had real problems with light when I was taking my photos.  I did get some nice shots of this flatheaded mayfly, Maccaffertium vicarium.   In many fly fishing guides, it's still known as Stenonema vicarium, but I'm sure they'll be brought up to date one of these days. To those of us aching to get to the streams in the spring, it's the "American March Brown," one of the earliest hatches we see.  Unfortunately, there are no trout to key on these nymphs this far down the Doyles.

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But where are the small and large winter stoneflies (Capniidae and Taeniopterygidae)?  I really looked hard this morning because they should be crawling around in the leaves.  Last year, I found this "small" small winter stonefly on October the 10th in this very river...

and I found this large winter stonefly on 10/27.

I'm not sure if they're delayed for some reason this year, or if I just haven't found the right leafpack!
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Lots of Eccoptura common stoneflies this morning, and I managed a few decent photos.

Most Eccoptura nymphs that I see are tan to yellow, like the one in the first photo above: I'm not sure why the abdomen is so brown on the nymph in photo two.  Is it a gender distinction?
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Finally, I found the same Perlodids here in the Doyles as I found last week at Buck Mt. Creek -- Clioperla clio and Helopicus subvarians.   But one of the Perlodids I found was simply too small to ID.  Size?  2.5 mm.

Tomorrow, off to a small stream in Sugar Hollow.

One by one the new Perlodids appear: Helopicus subvarians and Clioperla clio

There are days in this business when you find exactly what you're expecting to find, and today was one of those days.  This morning when I drove out to Buck Mt. Creek, I thought it likely that I'd start to see the Perlodid stoneflies Helopicus subvarians and Clioperla clio -- and I did.  Of course, both insects were still very small: the Helopicus nymph in the picture above was -- I'd guess -- about 10 mm in length; the Clioperla was smaller, maybe 6 or 7 mm.

Helopicus nymphs are easy to spot by their colors and the pattern we find on their heads -- "frons with a complete dark transverse band through [the] ocellar triangle."   (Beaty, "The Plecoptera of North Carolina," p. 21)  On H. subvarians nymphs, the leading edge of this band is a "straight line or nearly so." (Beaty, p. 21)   While there is a slight "dip" in the anterior edge of the band on this small nymph, we will not see that on the more mature nymphs later on in the winter -- like this one from 2/6 of this year also found at Buck Mt. Creek.

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C. clio nymphs, on the other hand, are not so easy to distinguish when they're small like the one that I discovered this morning.

Not much to go on.

Still, one of the key features for the species ID can be detected -- the "large light area on [the] dorsum of [the] head." (Beaty, "The Plecoptera of North Carolina," p. 20)

That large, light area really stands out when the nymphs color up as they mature.

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Two other nice insects this morning at Buck Mt. Creek.

1. Giant stonefly, Pteronarcys dorsata (corners of pronotum are "produced," and no projections on the abdominal segments).

2. And a beautiful common stonefly, Acroneuria carolinensis.

The tergites are banded: "anterior half light and posterior margin of tergites dark."  (Beaty, "The Plecoptera of North Carolina, p. 14)  The reverse is true of the more "common" common that we've been seeing, Acroneuria abnormis.
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Perlodid stonefly, Helopicus subvarians....

skillfully performing a back flip!

Small beginnings: sorting through leaf packs at the Doyles

This isn't one of the "small beginnings," but who can resist starting with this spectacular small minnow mayfly.  Baetis pluto, male, not quite fully mature.   Key diagnostic features: "tergum 5 relatively pale, segments 6 and 7 almost completely dark...middle caudal filament 3/4 to subequal to lateral filaments, usually with distinct dark band on caudal filaments medially."  (Beaty, "The Ephemeroptera of North Carolina," p. 6)

I had good sunlight for this one, so I got some very nice photos -- it's a colorful nymph.

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But it was a morning for finding small insects -- those we'll watch develop and grow through the winter and spring.

1. Green stonefly (Chloroperlid), genus Sweltsa.  First of the season.

2. Pronggilled mayfly, genus Paraleptophlebia.  First of the season.

3. Brushlegged mayfly, genus Isonychia.  Not the first of the season, but one of the "palest" Brushlegged nymphs I've ever seen.  Obviously, just recently molted.

4. A "smallish" flatheaded mayfly, Maccaffertium vicarium.  First of the season.  This is one of the few streams in which I've seen this species.

We can pick this one out by noting the dark bands on some of the tergites and all of the sternites.

5. And then there was this small stonefly, the first thing I picked up this morning.

I was fairly certain it was the Perlodid stonefly, Diploperla duplicata.  The colors were right, and we start to see them at this time of year.   But no -- notice the thoracic gills sticking out at the sides.  So, it's a common stonefly, one with anal gills present.

Looks to be a young Eccoptura xanthenses, one on which the distinct yellow pattern at the front of the head is not very clear.

We should start to see small winter stoneflies anytime now.  I wouldn't be surprised to find them next week.  

The Skwala Perlodid stonefly: Back -- briefly -- to the Northwest

Just back from Oregon where we've been visiting our daughter in Portland.  On Sunday, we went to the North Fork of the Lewis River in southern WA where I just couldn't resist looking through leafpacks and turning over some rocks.  I found a number of stoneflies, all the same -- the Perlodid stonefly, genus Skwala: S. americana or S. curvata, I'm not really sure which.  You may recall that I found one in Montana in August as well, and as I noted in the entry I posted, the "Skwala hatch" is a major hatch in the Northwest in March and April.

For identification I've used Stewart and Stark, Nymphs of North American Stonefly Genera, pp. 448-451 (good illustrations on p. 450).   There they describe S. americana -- but remember they're describing a nymph that's fully mature: the nymphs I found were still very small.

1. head

"Head dark with lighter M mark forward of anterior ocellus and incomplete light mesal bar; 2 oval, light occipital spots inside eyes, broken with reticulate dark lines and bordered behind by narrow band of stout spinules."  Works very well.

2. lacinia

"Lacinia bidentate with tuft of setae on a low knob below subapical tooth and continuous inner row of marginal setae."  You bet.

3. mesosternal ridge

"Y-arms of mesosternum reach anterior corners of furcal pits."  For sure.

I hope I get to see some mature nymphs some spring.  But even these immature nymphs were colorfully patterned.

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I only had a short time to look for some insects, but I also managed to find a few mayflies -- the small minnow mayfly, Baetis tricaudatus, and what appeared to be a small Leucrocuta flathead.

1. B. tricaudatus, male

(and check out those eyes!)

Baetis tricaudatus, female

2. And the small Leucrocuta

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(Lucia Falls on the North Fork of the Lewis.  Spectacular!)

Off to Sugar Hollow: The first Perlodid stonefly of the young season, Malirekus hastatus

This is not something I expected to find in Sugar Hollow this morning, but it was the very first insect that I picked up.  The Perlodid stonefly, Malirekus hastatus.  The small stream that I went to is a stream in which I've found them before.  This is one that I collected there on February 13th, 2012.

Gorgeous!  But it's also a "killer."  Don't put these in a tray where you're keeping small mayflies!

A quick review of how this one is ID'd.  "Nymphs 15-19 mm; distinctive pale "M" pattern on head; conical submental gills; triangular lacinia with low marginal knob bearing a tuft of setae and venral surface with a cluster of approximately 50 clothing hairs near base; single curved row of spinules on back of head, obsolete near midline."  (Steven Beaty, "The Plecoptera of North Carolina," p. 26)  Those features look like this.

1. head pattern (for a detailed description, see Stewart and Stark, Nymphs of North American Stonefly Genera, pp. 416-417)

2. conical submental gills

3. triangular lacinia

4. clothing hairs on ventral lacinial surface

5. and the row of spinules on the back of the head

So, the Perlodid stoneflies are here -- my favorite time of the year!

But I was in for another surprise when I found this very small mayfly.

It's the spiny crawler, genus Eurylophella.  What on earth is it doing here now?  This is an insect I expect to see in the spring, but here it is in October.  The key feature marking the Eurylophella genus ID is already easy to see: the large operculate gills on segment 4, the gills that cover those on segments 5-7.

Given its size -- 2.5 mm -- I doubt that I'll be able to determine the species.  The species I see in Buck Mt. Creek is E. verisimilis.  But my friend who explores these small streams in Sugar Hollow in a regular way has found E. funeralis as well.  I'll have to give the ID a try.
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What else?

1. Giant stoneflies, Pteronarcys proteus.  They are plentiful in this stream, and some, like this one are starting to get pretty big.  (Note small "Roach-like" stonefly [Peltoperlid] riding on its side.)

2. Common stonefly, Eccoptura xanthenses.  Also a species we commonly see in these small mountain streams.

3. And a few common netspinner caddisfly larvae: Diplectrona modesta and Hydropsyche betteni.  (Note the low, rounded tubercle at the back of the head on H. betteni.)

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Perlodid stonefly, Malirekus hastatus.