Back to Entry Run -- and one more time on the Acroneuria carolinensis/lycorias issue

Safely back from Entry Run: apparently no one thought I looked like a deer (!)

I found a fair number of Perlids -- common stoneflies -- this morning, and most looked like the one in the photo at the top of the page, which I think is Acroneuria carolinensis.  But you'll recall that this ID is an issue (see the entries from 10/23/14 and 10/28/14).  Acroneuria lycorias nymphs look exactly the same.  And while Frison says they can be distinguished by the presence (lycorias) or absence (carolinensis) of anal gills, Beaty argues the distinction isn't that clear.   According to Beaty (in one of the e-mails he sent me), they have found both types of nymph (with and without the gills) in the very same water, so they're not sure that the gills are a real point of distinction.  However, in that same e-mail he told me that if every nymph that I find in the same section of the same stream has them or lacks them (anal gills) then I can probably feel certain about the ID.

The nymphs that I found this morning did not have anal gills.  The nymphs that I found in the upper Doyles River -- similar water to Entry Run -- on 10/23 did not have anal gills.  Every nymph in my reference vial -- and I think they're all from the Doyles -- lacks gills.  I have only found one of these nymphs with the gills -- the one I found on 10/28 at Buck Mt. Creek.  This one.

And these are the gills.

Acroneuria carolinensis has a tolerance value of 1.2; Acroneuria lycorias has a tolerance value of 2.1.  Entry Run and the upper Doyles River are both very clean mountain streams, both of them in or near the Blue Ridge: Buck Mt. Creek, while being a very good stream, runs through farm land away from the mountains.   Pretty clear where I'm going: I think we've got A. lycorias in Buck Mt. Creek but A. carolinensis in Entry Run and the Doyles.   That's my working hypothesis at the moment.
_________________

More photos from Entry Run.

1. More pix of two of the A. carolinensis nymphs that I found this morning.

2. A "weighted-case maker" (Goeridae): Goera fuscula.  They're still around.

Note the sternal plates -- one of the features that helps us with the species ID.

3. A spiny crawler mayfly -- first of the season: Ephemerella invaria (the one with tubercles on the rear edges of the terga).

4. Giant stonefly: Pteronarcys proteus.

5. And another "first of the season," a Uenoid case-maker: Neophylax consimilis.

Dates for the entries in which you can find the evidence for species ID

(Where I plan to be going tomorrow: South River valley on the way to Entry Run.)

Whenever I give the name (Latin) of an insect in a photo I've posted, I worry that recent readers will wonder how I've established that species (or in some cases genus) ID.   So, I've worked back through my previous entries and noted some of the dates where you can find the evidence for specific identifications.  This project is not yet complete: there are still some gaps that I want to fill.  But, this should be a good place to begin and something I hope will be useful.
______________

                    EPT Species List for Central Virginia

               (Albemarle, Greene, Madison, Fluvanna)

                 

I. Ephemeroptera (Mayflies)

1. Ameletidae

1. Ameletus lineatus 4/11/13

2. Ameletus cryptostimulus 4/11/13

2. Baetidae (Small minnow mayflies)

1. Acentrella nadineae 8/6/11

2. Acentrella turbida 9/30/11

3. Baetis flavistriga 6/6/12

4. Baetis intercalaris 5/28/12

5. Baetis pluto 5/11/12

6. Baetis tricaudatus 2/19/12, 3/5/13

7. Heterocloeon curiosum 7/26/13

8. Heterocloeon amplum 10/11/11, 2/7/12, 1/24/13

9. Heterocloeon petersi 9/18/12

10. Iswaeon anoka 6/25/12

11. Labiobaetis propinquus 8/8/13

12. Plauditus dubius 4/10/12, 5/12/12

3. Isonychiidae (Brushlegged mayflies)

1. Isonychia

4. Heptageniidae (Flatheaded mayflies)

1. Cinygmula subaequalis 3/27/12, 5/4/14

2. Epeorus pleuralis 6/22/11

3. Epeorus vitreus 6/22/11

4. Epeorus fragilis, 5/26/13

5. Heptagenia marginalis 6/14/12

6. Leucrocuta hebe 8/9/12, 5/9/14

7. Leucrocuta sp. (juno?) 5/9/14

8. Leucrocuta sp. (aphrodite?) 5/9/14

9. Leucrocuta sp. (thetis?) 5/9/14

10. Maccaffertium ithaca 6/14/12

11. Maccaffertium meririvulanum 12/13/11, 1/17/12

12. Maccaffertium pudicum

13. Maccaffertium vicarium 10/6/11,  10/10/11

14. Maccaffertium modestum 6/13/14

15. Rhithrogena sp. (exilis?) 5/17/14

16. Rhithrogena sp. 5/17/14

17. Stenacron carolina 6/26/14

18. Stenacron interpunctatum 6/26/14

19. Stenacron pallidum 6/26/14

5.  Ephemerellidae (Spiny crawler mayflies)

1. Drunella cornutella 5/27/12, 5/23/14

2. Drunella tuberculata 4/23/12, 5/17/13

3. Drunella walkeri 4/19/12

4. Ephemerella dorothea 9/16/11, 3/16/13

5. Ephemerella invaria 3/3/12

6. Ephemerella subvaria 9/16/11

7. Eurylophella verisimilis 4/26/12, 5/25/13

8. Eurylophella funeralis

9. Eurylophella sp. (minimella?)

9. Serratella serratoides 6/26/12

10. Serratella serrata 6/26/13, 6/27/13

11. Teloganopsis deficiens 6/13/12

6. Leptohyphidae (Little stout crawler mayflies)

1. Tricorythodes

*7. Caenidae (Small square-gill mayflies)

1. Caenis

*8. Baetiscidae (Armored mayflies)

1. Baetisca

9. Leptophlebiidae (Pronggilled mayflies)

1. Paraleptophlebia mollis 7/25/13

2. Paraleptophlebia guttata 7/25/13

3. Habrophlebia vibrans 6/8/11

4. Leptophlebia 12/23/12

10. Ephemeridae (Common burrower mayflies)

1. Ephemera guttalata 5/2/12, 4/10/14

II. Plecoptera (Stoneflies)

1. Capniidae (Small winter stoneflies)

1. Allocapnia 11/14/12

2. Paracapnia angulata 1/30/12, 12/13/13

2. Leuctridae (Needleflies)

1. Leuctra 2/23/12

3. Nemouridae (Forestflies)

1. Amphinemura sp.

2. Amphinemura sp. (wui?)

3. Prostoia completa 1/17/12

4. Soyedina sp. (washingtoni?) 3/5/13, 12/18/13

4. Taeniopterygidae (Large winter stoneflies)

1. Strophopteryx fasciata 12/15/11, 1/21/14

2. Taenionema atlanticum 12/11/11

3. Taeniopteryx burksi/maura 11/12/12

5.  Chloroperlidae (Green stoneflies)

1. Alloperla 5/26/12

2. Haploperla brevis 4/11/14

3. Sweltsa 12/22/11

6. Peltoperlidae (Roach-like stoneflies)

1. Peltoperla 10/20/11

2. Tallaperla 10/20/11

3. Viehoperla ada

7. Perlidae (Common stoneflies)

1. Acroneuria abnormis 9/13/13

2. Acroneuria carolinensis 10/23/14

3. Acroneuria sp. (possibly internata, possibly a variety of abnormis) 4/20/14, 4/22/14

4. Acroneuria arenosa (possibly A. evoluta) 9/1/14

5. Acroneuria lycorias 10/23/14, 10/28/14

5. Agnetina annulipes 9/13/12, 9/26/14

6. Agnetina capitata 5/26/14, 9/26/14

7. Agnetina flavescens 11/10/13, 9/26/14

8.Eccoptura xanthenses

9. Neoperla 6/21/11

10. Paragnetina immarginata 11/2/14

11. Paragnetina fumosa 4/17/13

12. Perlesta 6/3/12

8. Perlodidae (Springflies and Stripetails)

1. Clioperla clio 10/4/12

2. Diploperla duplicata 11/3/12

3. Helopicus subvarians 4/2/11

4. Isogenoides hansoni 12/6/12, 1/19/14

5. Isoperla dicala 5/11/12, 4/13/13

6. Isoperla holochlora 4/5/14

7. Isoperla nr. holochlora 4/5/14

8. Isoperla montana/kirchneri 4/30/13, 4/7/14

9. Isoperla similis 11/12/11, 2/24/14

10. Isoperla davisi 4/14/13

11. Isoperla orata 6/2/13

12. Isoperla nr. orata 5/8/13, 4/7/14

13. Isoperla sp.1 4/7/14

14. Isoperla sp.2 4/7/14

15. Malirekus hastatus 1/21/12

16. Rememus bilobatus 5/3/12

9. Pteronarcys (Giant stoneflies)

1. Pteronarcys biloba 2/18/12

2. Pteronarcys dorsata 8/16/13

3. Pteronarcys proteus 11/10/12

III. Trichoptera (Caddisflies)

1. Rhyacophilidae (Free-living caddisflies)

1. Rhyacophila carolina 3/7/12, 3/20/13

2. Rhyacophlia fuscula 1/6/12

3. Rhyacophila nigrita 2/10/14

4. Rhyacophila glaberrima 3/11/14

5. Rhyacophila ledra/fenestra 4/19/13

6. Rhyacophila sp. (banksi?) 1/28/14

*2. Hydroptilidae (Micro caddisflies)

1. Hydroptila (?)

3. Glossosomatidae (Saddle-case makers)

1. Glossosoma nigrior

4. Philopotamidae (Fingernet caddisflies)

1. Chimarra 1/12/12

2. Dolophilodes distincta 1/12/12

3. Wormaldia 1/12/12

5. Polycentropodidae

1. Polycentropus 7/19/11

6. Hydropsychidae (Common Netspinners)

1. Ceratopsyche alhedra 10/19/12

2. Ceratopsyche bronta 8/1/12

3. Ceratopsyche morosa 8/1/12

4. Ceratopsyche slossonae 9/6/12

5. Ceratopsyche sparna 7/31/12

6. Cheumatopsyche 12/27/12

7. Diplectrona modesta 3/17/12

8. Diplectrona metaqui

9. Hydropsyche betteni 10/16/12

10. Hydropsyche rossi 10/10/12, 7/7/13

11. Hydropsyche venularis 8/4/12, 10/10/12, 7/26/13

12. Macrostemum sp. 8/2/12

8. Brachycentridae (Humpless case-makers)

1. Adicrophleps hitchcocki 12/2/13

2. Brachycentrus appalachia 7/10/12

3. Micrasema wataga 7/10/12

4. Micrasema charonis 4/25/13

5. Micrasema bennetti

6. Micrasema scotti (?)

9. Lepidostomatidae

1. Lepidostoma 12/13/11

10. Limnephilidae (Northern case-makers)

1. Ironoquia punctatissima

2. Pycnopsyche gentilis 9/14/12

3. Pycnopsyche scabripennis 9/14/12

4. Pseudostenophalyx sparsus 3/12/14

11. Apataniidae

1. Apatania incerta 12/9/12

12. Goeridae

1. Goera calcarata 11/3/13

2. Goera fuscula 10/27/13

 13. Uenoidae (genus, 11/27/12)

1. Neophylax oligius 3/18/13

2. Neophylax consimillis 1/5/13, 3/18/13

3. Neophylax aniqua 1/23/13, 3/1813

4. Neophylax mitchelli 1/21/13, 3/18/13

5. Neophylax fuscus 12/27/13

6. Neophylax concinnus 2/7/13

7. Neophylax sp.

14. Leptoceridae (Long-horned case-makers)

1. Nectopsyche exquisita 9/3/12, 8/9/14

2. Oecetis

3. Ceraclea maculata 5/6/13

15. Odontoceridae (Strong case-makers)

1. Psilotreta labida 11/19/13

2. Psilotreta frontalis 10/29/13

3. Psilotreta rufa 11/17/14

16. Molannidae (Hooded-case maker)

1. Molanna blenda 11/11/14

________________________

I will continue to update this list and fill in the gaps when I can.  Off to the upper reaches of Entry Run in the morning where I hope I won't be shot by someone who thinks I look like a deer!  Dangerous times to work in the mountains.

A third strong-case maker (Odontoceridae) larva: Psilotreta rufa

We appear to have found a third stong-case maker species: Psilotreta rufa.  (Well, there's no "we" involved: the larva was found by my friend in Sugar Hollow, the one who lives next to this superb little stream.)

We've collaborated on the ID, but all of the photos of rufa were taken by her.
_______________________

Almost all of the Odontocerids I see are Psilotreta labida, a larva with a broad dark stripe extending from the head through the mesonotum and long, pointed anterolateral pronotal projections.

You'll recall that I found hundreds of them just a few weeks ago in the Rapidan River.  The only other species I've seen -- and I've only found it in one little stream -- is Psilotreta frontalis.

We see that same dark band on P. frontalis -- but the pronotal projections are short.

Clearly, the larva my friend found last week is something entirely different.  There is no dark band on the head and the nota: rather, the head and pronotum are a dark, reddish brown while the mesonotum is almost entirely yellow.

_______________

Our new larva keys out to Psilotreta rufa which Beaty describes in the following way.

(P. rufa) -- larvae up to 11 mm; head and pronotum uniformly reddish brown without stripes but may have darker pigmentation along frontoclypeal and coronal sutures...head longer than wide and relatively flat between carinae; seta 17 about half the length of seta 15; pronotum darker laterally; anterolateral pronotal projections short.  ("The Trichoptera of North Carolina, p. 97)

The color of the head and pronotum, the shape of the head (longer than wide), and the short pronotal projections all show up very well in the following photo.

We might see darker pigmentation along the frontoclypeal suture in the following photo -- but the color distinction is admittedly slight.

But this very nice lateral photo clearly shows that the pronotum is dark laterally, and, I think, that the head between the carinae is "relatively flat."  (The carinae are the raised ridges that run from front to back on either side of the head.)

That leaves us with the question of the relative lengths of seta 17 and 15.  I confess that I had no idea where to look for these setae until we found the following article, one that is referenced by Beaty:  C.R. Parker and G.B. Wiggins, "Revision of the caddisfly Genus Psilotreta (Tichoptera: Odontoceridae)," ROM (Royal Ontario Museum): Life Sciences Contributions, No. 144 (1987).  In that article, on p. 29, the head and nota of P. rufa are illustrated in detail, and setae 17 and 15 are clearly marked: 17 is behind the frontoclypeal suture, and 15 is along the carina, the ridge.  Unfortunaely, despite the very fine photos my friend has provided, I can't be sure I can pick out those hairs!

Nonetheless, Parker and Wiggins describe P. rufa in a way that supports our identification.

p. 10  "head uniformly reddish brown or with pale areas laterally; thoracic nota uniformly reddish brown to pale yellowish."  Yes.

p. 21  "Head longer than wide, and in lateral aspect posterodorsal angle more or less squared; dorsum relatively flat between carinae; seta 17 thinner than, and usually about one-half as long as, seta 15.  Pronotum with projection of anterolateral corner short, about 0.2X middorsal length of pronotumn.  Mesonotum with black marking along posterior ridge extending laterad to posterior inflection."

The point of inflection is where the thin band we can see above the thicker black band rises up at the side.  If you look closely you can see it in the following photo.

_________________

I'm not sure we really need to see the head setae to make this identification given the preponderance of evidence that we have.  Psilotreta rufa.

________________

Two final points of interest.  1) The habitat for P. rufa (Parker and Wiggins, p. 21) is a perfect match for our stream: "P. rufa larvae occur in small spring seeps and spring-fed streams."   And 2) Parker and Wiggins include the following site among the locations where rufa is found: Albemarle County in Virginia, south fork of the Moormans River above the Charlottesville Reservoir. (p. 22)  Bingo!  Not at all far from the small stream in which this larva is living.

Some nice photos from Sugar Hollow

I'm going on record: in the future when it's 34º and windy, I am not going out to the streams!  Wow -- that was cold.

I went to one of our good, headwater streams in Sugar Hollow this morning hoping to find -- what else? --  Molanna, since I've not yet seen one myself.  So I focussed on silt-covered rocks in still water pools.  No luck.  I did continue to see "weighted-case makers" (Goera fuscula) and decided to take some photos of this larva since it had made this colorful, kind of lopsided case.

Other pix of the same larva.

Note the pronotal and mesonotal anterolateral projections, key features on the Goerids.

What a beauty.
___________________

In the leaf packs I saw a number of insects, including a lot of Giant stoneflies, some of which were  getting quite large.  This one was 35 mm.  Pteronarcys proteus.  (Good lighting makes for good photos.)

________________

A couple of oddities.  Number one, this small common stonefly.

Strange colors -- but it may be a nymph that just recently molted.  No anal gills, and no setal row on the occipital ridge.  That normally means Acroneuria abnormis, and there is an A. abnormis population that inhabits this stream.  However, if it is A. abnormis, it appears to the "brown" one, the one that lacks a clear yellow "M" on the head and has an abdomen that's uniformly brown.   But -- "early times," as the British would say.

Number 2 is this little case that I found.

I couldn't see a larva inside, so I brought it home for a microscope look.  It was abandoned.  But it appears to be the case of a young Uenoid, the case-maker that will soon be showing up in large numbers in all of these streams.
________________

No warm up for most of a week.  Hope to get out next Thursday.

A significant find in Sugar Hollow: new taxon -- the "hooded-case maker" (Molannidae), Molanna blenda

While I was taking advantage of our beautiful weather to play some golf yesterday, my friend in Sugar Hollow was adding a new caddsifly to our EPT list for central Virginia: the "hooded-case maker" Molanna blenda.

Molannidae is often found in still water -- "lakes or the slower currents of rivers and streams" (Wiggins, p. 290), where they are not often easy to find since they "inhabit the sand and mud substrates of these sites."  (Wiggins, Larvae of the North American Caddisfly Genera, 1st ed., p. 290)
But they can be found in "cool spring-fed streams" (Beaty, "The Trichoptera of North Carolina," p. 96) which is where this one was found.  It was on a rock, covered with silt, but gave itself away when it moved.   The stream is that special 1st order stream that flows close to my friend's home.  This one.

Hooded-case makers get their name from their cases -- which indeed have a hood, or "cowl," at the anterior end, and the case is "flanged" on the sides.  Ames notes that the cases also have "a ragged posterior opening on the dorsal side" (Thomas Ames, Caddisflies: A Guide to Eastern Species for Anglers and Other Naturalists, p. 206).   E. g.

dorsal view

ventral view

As you can see, the hood almost completely covers the head of the larva.   For the genus ID -- and there's only one genus in our part of the country, Molanna -- we need a close look at the claws on the hind (metathoracic) legs.  Beaty, "Claw of metathoracic leg shorter and more stout than claws of other legs and setose." (p. 96)  I think we can see that in this live picture (my friend prefers not to preserve any insects).

Beaty's description of M. blenda reads as follows: "larvae 10-12 mm; apex of base of tibial spine extends well past tibiotarsal joint; membranous area at constriction of frons capitate; moderately wide black banding along frontoclypeal and coronal suture."  ("Capitate" means "abruptly enlarged and globular.")  I can't make a call on the tibial spine, but the "enlarged globular" membranous area at the front of the head is very clear in our photos as are the wide black bands that border the frontoclypeal suture.  Another view.

_________________

Very cool.  Obviously it's time for me to get my priorities straight and get back to the streams!  Still, it's so nice to play golf at this time of year :)  (Behind the 9th green at Meadow Creek golf course in Charlottesville.)

_________________

(Please note that all photos of the Molanna were taken by my friend and posted with her permission.)

The Perlodid stonefly Helopicus subvarians appears at the Doyles

First of the season: Perlodid stonefly, Helopicus subvarians.    It's one of the few stonefly nymphs that we see that's colorful from the very beginning.   It's also one of the biggest -- longest -- Perlodid stoneflies we see -- 17-20 mm when it's mature.  And they're quite striking when they're mature.

2/27/14 -- not yet mature.

3/14/12 -- fairly mature

2/6/12 -- very mature.

________________

According to Stewart and Stark (p. 400), subvarians is the only Helopicus species we find in VA, and the distinguishing feature of this particular species is the fairly straight anterior edge of the dark transverse band on the head (Beaty, "The Plecoptera of North Carolina," p. 21).   While that straight edge is very clear in the 2/6 photo above, that is not the case with the immature nymphs from this morning.

With a tolerance value of 1.2, it's a species we find in fairly clean streams.  I always see lots of them in the Doyles and at Buck Mt. Creek.
_________________

________________

Another day when taking photos was tricking: breezy with fast moving clouds.  Still, awfully nice out there at the moment.