Wednesday, March 6, 2019

Ironoquia punctatissima: a new caddisfly casemaker in a small stream in Sugar Hollow


Yesterday afternoon, I went with a friend to a tiny stream in Sugar Hollow, one in low-lying ground.  It was shallow and slow-moving, just a couple of feet wide, but there were some small riffles here and there and the occasional leaf pack.  To our surprise, we saw a fair number of insects including this casemaker which turned out to be Ironoquia punctatissima (Limnnephilidae).

Two things were clear from the very beginning in terms of key features: for one the case was rounded and slightly curved, seemingly made out of rows of pieces of bark, and secondly, the gill tufts were multi-branched.  Take a close look.


Leafing through Wiggins -- Glenn B. Wiggins, Larvae of the North American Caddisfly Genera (Trichoptera) -- I found what looked to be a pretty good match in the Limnephilidae genus, Ironoquia, so that's where I began. (pp. 249-249 in the 1977 edition)  On the genus morphology, Wiggins wrote the following things: "Ironoquia, one of four North American limnephilid genera in which most abdominal gills of the dorsal and ventral rows have more than four branches, is distinct from the others in having more than two (usually five) major setae along the ventral edge of the middle and hind femora.  Many metanotal setae arise from the integument between the primary sclerites.  Length of larva up to 22 mm."  All of this worked out to be perfectly true.  Here are the key microscope photos.  (And this larva was about 18 mm.)





For additional confirmation, we can look at what he says about the type of case and the habitat in which this genus is found.

"CASE  Two types of larval case are known.  In I. punctatissima and I. lyrata cases are made of bark and leaves, curved but little tapered; the case of I. parvula is made of sand grains." (p. 248)

"BIOLOGY Although North American larvae of the subfamily Dicosmoecinae are largely restricted to cool, running waters, species of Ironoquia are the sole exception, living in temporary pools and streams." (p. 248)

Beaty says much the same on the habitat of this genus: "Found in temporary streams as well as swamp streams." ("The Trichoptera of North Carolina," p. 82)  I have no problem thinking that this was a temporary stream, one that dries up in dry summers.

What about the species?  For this I had to turn to the new book by Morse, McCafferty, Stark, and Jacobus -- Larvae of the Southeastern USA: Mayfly, Stonefly, and Caddisfly Species (Clemson University, 2017).  They note, and illustrate, two possibilities: punctatissima and parvula. (pp. 392-393)  The difference between the two has to do with the head and nota.  For Ironoquia punctatissima -- "Head and nota pale with dark spots and infuscations" (p. 392): and for Ironoquia parvula -- "Head and thoracic nota dark with pale central stripe" (both types of head are illustrated on p. 393)  No doubt about it, we've got a head that is pale with dark spots.



Ironoquia punctatissima -- so much fun to finding something new.
___________________________

We also found a mayfly that might be a new species for me -- Eurylophella funeralis.


But these little nymphs are hard to get down to the level of species.  To do that, we need a clear look at the abdominal tubercles, and the two nymphs we found yesterday were dirtied up with detritus.  (Sigh.  I wish someone made a tiny, tiny brush that we could use to clean these guys up!)  (:

In any event, we really enjoyed taking a look at this stream, and you can be sure we'll work on it more in the near future.

Tuesday, February 5, 2019

Photos from the South River and Entry Run


The weather was perfect yesterday so I headed up to Greene County to look for bugs in Entry Run and South River.  I wasn't disappointed.  On some of the rocks I turned over, there were 20-30 nymphs, both Epeorus pleuralis (Quill Gordons to fly fisherman) and Baetis tricaudatus small minnow mayflies.  It was really awesome.  It wasn't hard to get some pretty good photos.

1. Baetis tricaudatus, female, several shots including the one at the top of the page, and one with one nymph on its side and another on its back.




2. A flatheaded mayfly, Epeorus pleuralis.



3. A "common netspinner," Hydropsyche (C.) alhedra.  Remember that this netspinner species is very intolerant, rating 0.0 on a scale of 0-10.




and 4. A "free living" caddisfly larva, Rhyacophila fuscula, with a good look from the side and underneath.



___________________


Thursday, January 31, 2019

Photos from the Rapidan River


I went up to the Rapidan River on Monday to see if I could find any insects.  The water was high and fast, but I found quite a few things in balls of vegetative matter close to shore.

At the top of the page, a pretty cased caddisfly that really drew my attention.  The case looked a little unique, and at first I thought it might be a species I'd not seen before.


I preserved it and went home to do some microscope work.  The first thing to check was the lateral hump which looked like this.


The orange sclerite behind the hump signaled genus Pycnopsyche.  Since I often find Pycnopsyche scabripennis up there in the spring and summer, that immediately came to mind.  But the case looked somehow different.  At issue, the sticks extending back from the top of the case.  This brought to mind P. guttifera, a species that often makes this kind of case.  From the descriptions of Pycnopsyche larvae in Beaty's manual ("The Trichoptera of North Carolina," pp. 84-85) it became clear that the choices were guttifera or scabripennis.  These species share one thing in common -- both have "2 major setae" on the "ventral margin of the femora" (Beaty, p. 85).  That I could see.


(Note that the large setae behind these two is actually on the dorsal side of the femur.)  But, the species differ in one significant way -- on the venter of the first abdominal segment, there are more than 15 setae on guttifera, while on scabripennis there are less.   Microscope photo.


I've pointed to three of the setae; in all I counted ten.  So, I guess it was P. scabripennis after all, just a young one with much room to grow. 


Since I was so intent on getting good pics of the caddis, I totally ignored the spiny crawler mayfly that was hitching a ride on its case.  Pretty sure it was Ephemerella invaria, but I should have preserved it just to be sure.  Very unusual colors.

________________

I got some pretty good photos of two other insects.

1. Small minnow mayfly, Baetis tricauditus, male and fully mature.



and 2.  A young "Yellow Sally" stonefly, Isoperla kirchneri group (probably I. montana).


_________________

The Rapidan valley in Winter.


Wednesday, January 30, 2019

Another free-living caddisfly species -- Rhyacophila torva


This is an exciting find I made a few weeks ago while exploring one of my favorite streams in Sugar Hollow.  The stream is on the land of a good friend who often goes with me to look for stream insects. 

This is Rhyacophila torva, which brings the number of Rhyacophilidae species that we've found so far to seven.  It's the distinctive head pattern that convinced me that this was a new one for me, and it's the head pattern that's one of the keys to the species ID.


On R. torva, Beaty says the following: "R. torva -- larva ?? mm; teeth on anal claw present; distinct dark "V" along frontoclypeal sutures with some darker muscle scars behind.  Occurs mostly in small Mountain streams.  Relatively common.  Recorded from GSMNP. (Steven Beaty, "The Trichoptera of North Carolina," p. 61.)

With that, all I had to do was get a microscope shot of the anal claws, and the teeth on the claws was obvious.  (In another source -- unpublished -- there's an illustration of an R. torva claw.  It too shows a claw with 3 teeth that are progressively smaller as you move the tip to the rear.)


I should add that, yes indeed, it was found in a small mountain stream!


Love finding new things!
_________________________

As you can see from the photo above, it was a gorgeous day, one of the few really nice days we've had so far this winter.  Consequently, we found a few other things that made for good photos.

1. Small minnow mayfly, Baetis tricaudatus




2. A second Rhyacophilidae species -- R. carolina



and 3. A Roach-like stonefly, Tallaperla sp.


__________________

I'll be posting again tomorrow -- photos from a trip to the Rapidan river I took yesterday.  Got some good ones.

One other thing. For the last year I've been actively posting on Instagram.  You can find me at: buddhabob2hanlubo.

Big News: Isoperla sp. VA has been identified as Isoperla nelsoni


I have several entries to post, but I'll start with some big news from Steve Beaty.  The Isoperla stonefly nymph that we've been finding in a number of small streams in Sugar Hollow which had the temporary designation of Isoperla sp. VA has now been identifed as Isoperla nelsoni.  Exciting news to those of us who see it every spring -- usually in April and May -- but have failed to find any adults to help us with the ID.

Isoperla nelsoni, the adult, was first described in a long article by S.W. Szcytko and B.C. Kondratieff, pp. 174-177 in "A Review of the Eastern Nearctic Isoperlinae (Plecoptera: Perlodidae) With The Description of Twenty-two new species," Monographs of Illesia, Number 1:1-289 (2015). 

One thing of interest, the head pattern we see on the mature nymph, this,


with a dark patch enclosed in the ocellar triangle and a dark patch anterior to it, shows up as well on the head of the adult.  (See the illustration of that on p. 175 of the article.)

Exciting news.  We had found this nymph first in May of 2011.


Friday, October 26, 2018

New Insects from Oregon: Drunella spinifera and Rickera sorpta


It's been awhile since I've posted an entry, but it's been awhile since I found anything new.  But I lucked out last week when we went to visit our daughter in Oregon.  On a trip up to Mt. Hood, we stopped at a small stream in which I found some new -- for me -- insects.

Let's start with the easy one, the spiny crawler mayfly, Drunella spinifera.  (In the photo above and the photo below)


As I always do when I try to ID bugs from the Northwest, I turned to the website managed by Roger Rohrbeck, PNW Mayflies (Fly Fishing Entomology).  Rohrbeck describes seven different species of Drunella nymphs, and the one that works for us is Drunella spinifera.   His description reads: "Femora of front legs very broad, but don't have bumps on front edge; long sharp tubercles on back of head; abdominal tubercles 8-9 more than twice as long as 2-7."  Here's a look at the fore femora:


Other species of Drunella do have bumps on the front edge.  E.g., in case you've forgotten, here's a look at the fore femora of Drunella cornutella, a species we find in our streams in VA.


Dramatically different.  The shot I took of the tubercles on the head --


don't show the "sharpness" very well (bad angle on my part), but check out the tubercles on the abdominal segments.


The tubercles on segments 8 and 9 differ markedly from those on 2-7.  No doubt about it, our nymph is Drunella spinifera.  I might add that on his website "troutnut.com," Jason Neuswanger notes that this is a species that "prefers cold water," and inhabits "high elevation headwaters."  We were at about 3000' ASL.
________________

Now on to the toughy.


As you can see,  it was a very small stonefly nymph which makes the ID all the more difficult.  However, I have reason to believe that it was Rickera sorpta.  This genus and species is described on p. 440 of Stewart & Stark, Nymphs of North American Stonefly Genera.  There, the head is described in the following way: "Head with dark, broad, irregular U-shaped mark connecting ocelli; light oval interocellar spot. Light area anterior to median ocellus."


On target so far.  On the lacinia -- "Lacinia triangular and unidentate, with 5-6 basal marginal spinules and 2-3 medially located marginal spinules."


Unidentate for sure.  I didn't note any spinules, but this was a very small, very young nymph.  Now for a critical feature.  "Y-arms of mesosternum meet posterior corners of furcal pits, and transverse suture connects anterior corners of furcal pits."  The connecting suture is illustrated on p. 442 (Fig. 14.50), and it appears to be in the shape of a slight arc.  Here's the best photo that I could manage.


I've put a rectangular box around this suture to help us focus.  I'd say they're connected for sure.  One other feature.  Rohrbeck adds that there are "dark and light stripes on the abdomen" (PNW Stoneflies). 


And there they are. 

I only hesitate on my ID because there is another taxon -- Kogotus nonus -- that looks a lot light our little nymph.  The head pattern's much the same, and there are dark and light stripes on the abdomen, and the lacinia is unidentate.  This is one that I found a few years ago in Montana.


How do they differ?  It has to do with the presence or absence of that suture connecting the furcal pits of the mesosternal Y-ridge.  It's present on Rickera, absent on Kogotus.  I'll stick with my ID of Rickera sorpta, for the moment at least, since I do see that suture on our small nymph.

So much fun to find something new and to work on the species ID.  I should note, by the way, that I'm now posting photos on Instagram.  Look for me under "buddhabob2hanlubo".