Friday, December 28, 2012

Plenty of insects -- but not enough sun for good photos

Well, I mean, that's not a bad photo -- but all in all it was a frustrating day.

A lot of our streams are high and off color since we had some decent rainfall on Wednesday.  So, I went back to my small streams in Sugar Hollow which, coming down steeply from high up in the mountains, are running nice and clear.  And I found lots of insects: Uenoid caddis case-makers; flatheaded mayflies -- Epeorus pleuralis, Maccaffertium pudicum, and Maccaffertium merririvulanum; Giant stoneflies, all sorts of sizes; Green stoneflies; large winter stoneflies -- Taenionema atlanticum, the only species I see in this stream; and, as we see in the photo above, small winter stoneflies -- what I think is Allocapnia pygmaea.  But the sun disappeared -- which means the photography suffers.

But...I did get some shots that are worth showing.

1. More photos of that beautiful small winter stonefly which is almost mature: note the rich colors and patterns and the darkening wing pads.

2. One of the many T. atlanticum large winter stoneflies I saw.

3. A black fly larva -- I've not yet said anything, but I've been seeing a lot of them this year.  In the second photo you can actually see the eyes.

4. And the largest Epeorus pleuralis flatheaded mayfly I've seen so far this year.

But wait a minute -- what's that little nymph swimming next to it in the tray?  Any guesses?  Perhaps a bigger photo would help.

That is one small mayfly, and to help us with the ID,  let me point out four things: 1) the antennae are short, and they form a "Y" at the front of the head; 2) the gills are pointing straight up and down; 3) the body is "cigar" shaped; and 4) the tails/cerci are banded (though one of the three has broken off).  You might also note the shape of the eyes.

Here's one from February, 2011, one that's a little bit bigger, one on which those features show up a lot better.

And here's one from March of last year that I found in the same stream that I went to today.

Ameletidae, genus Ameletus.  I was amazed that I was able to see that tiny nymph flipping around on a leaf -- even more amazed that I got a respectable photo.  Size: 3 mm.   This is an excellent stream for Ameletids -- they live in cool, small mountain streams -- and I always see them here in the winter.  But, I've never seen such a small one before.  Fun!

Below: a decent photo of one of the M. pudicum flatheads that I found.

Thursday, December 27, 2012

Cheumatopsyche: the common netspinner genus that we "commonly" see in the winter

When I was at the upper Doyles river on 12/23, I found this odd-colored common netspinner larva.  I preserved it, to work on species ID when I returned home, thinking it might be a Ceratopsyche species I had not seen before.  But when I looked through the microscope, I quickly saw that it was a genus Cheumatopsyche which, with a TV of 6.6 is nothing special -- so I ignored it in the blog that I posted that day.  But I think that this might deserve comment.

I generally think of summer as "common netspinner season."  In a lot of our streams, this taxon is the most common insect we see from July through September -- even into October.  The tangled vegetation that grows on the rocks in the Rivanna is so loaded with them at that time of year that it sometimes gives me the creeps!  But, we find a lot of them in all of our streams at that time of year.  And if you look back at the blog entries written during that stretch of time, you'll see that that is when I was working intently on netspinner ID, finding mostly Ceratopsyche and Hydropsyche species.

After October, they just disappear -- well, the big numbers disappear anyway.  At the moment, I don't see many netspinners at all.  True, I found a Ceratopsyche bronta at Lickinghole Creek on 12/2, and I found a Ceratopsyche alhedra at the Rapidan river on 12/6.  But most of the common netspinners I see at the moment are genus Cheumatopsyche.  I can usually tell by the color: most that I see are bright green with a dark brown head and nota.  (Not true, as you can see, of the netspinner I found at the Doyles.)

Is there a reason why this is our "common" common netspinner during the winter?  I think that there is.  As it turns out, Cheumatopsyche larvae commonly start to hatch -- as the "Little Sister Caddis" -- in April, "as early as mid-April in more southerly locations..." (Thomas Ames, Caddisflies: A Guide to Eastern Species for Anglers and Other Naturalists, 2009, p. 131).  But we will continue to see some during the summer.  Again, let me quote from Ames: "Peak flight periods in the East are from April through July, with continued emergence into October." (p. 130)

While most of the larvae of this netspinner genus I see are bright green, they do come in a number of colors, so we can't rely on color to decide on ID.  Certain ID often requires microscope work -- but you often can see the critical features using a loupe in the field.

Look for two things.  1) There is a notch in the leading edge of the frontoclypeus (essentially the top of the head).  This:

2) If you can see the larva while it's on its back, you'll notice that -- in contrast to the Hydropsyche larva -- it lacks sclerites below the prosternal plate.  Let me illustrate:



I'll continue to look for common netspinners throughout the winter: that Cheumatopsyche is the most common genus we see at this time of year is a thesis that needs to be tested.   Of course, there is another netspinner we commonly see in the winter and spring -- but only in small mountain streams: Diplectrona modesta.  This one:


Cheumatopsyche photos:

3/7/12 (Whippoorwill Branch of the Mechums)

8/30/12 (lower Doyles River)

12/23/12 (Upper Doyles River)

Wednesday, December 26, 2012

Annual summary for 2012: the directions we'll take in 2013

(Above: the common stonefly, Agnetina annulipes, one of the new taxon discovered this year.)

This is a summary of where things stand with this blog at the end of two years, and some thoughts on current and future directions.

I. Statistics

I've been surprised with the interest shown in this blog, but pleased to know there are so many people who share my fascination with aquatic insects.  The number of page views at the moment -- after two years of posting -- stands at 54, 124.  The blog has been viewed from people from 128 different countries; as you might expect, the largest number of viewers is from the U.S.  The top five countries are:

1. United States: 34,958
2. Canada: 2427
3. United Kingdom: 1635
4. Russia: 1260
5. Romania: 814

The highest number of page views for a single month came in May: 3859.

II. What's been accomplished?

At the end of last year, some of you may recall, I thought about giving this up and moving on to something new.  Frankly, I was pretty sure that I had found all of the species I was going to find in our local streams -- that I'd have nothing new to say in future blog entries.  I could not have been more wrong.  By my count, I've found about 30 new insects this year, things I had not seen before, or things -- like common netspinners -- that I had never identified to the level of species.  Here's my list.  (Reminder: "new" simply means "new to my collection.")

Mayflies (Ephemeroptera)

A. Small minnow mayflies

1. Baetis tricaudatus (new)
2. Heterocloeon petersi (new)
3. Iswaeon anoka (new)
4. Plauditus dubius (new)

B. Flatheaded mayflies

1. Maccaffertium merririvulanum (new)
2. Cinygmula subaequalis (new)

C. Spiny crawler mayflies

1. Drunella cornutella (new)
2. Ephemerella invaria (newly identified)
3. Teloganopsis deficiens (new)

D. Other mayflies

1. pronggilled mayfly, new genus: Leptophlebia
2. common burrower mayfly: Ephemera guttalata (new)

Stoneflies (Plecoptera)

1. new small winter stonefly: Paracapnia angulata
2. new genus of green stonefly: Alloperla
3. new genus of green stonefly: Haploperla
4. new common stonefly: Agnetina annulipes
5. new common stonefly: Paragnetina media (Pennsylvania)
6. new Perlodid stonefly: Isoperla dicala
7. new Perlodid stonefly: Malirekus hastatus
8. giant stonefly species, now identified: Pteronarcys proteus

Caddisflies (Trichoptera)

A. Common netspinners, now identified to the level of species

1. Ceratopsyche alhedra
2. Ceratopsyche bronta
3. Ceratopsyche morosa
4. Ceratopsyche slossonae
5. Ceratopsyche sparna
6. Hydropsyche betteni
7. Hydropsyche rossi
8. Hydropsyche venularis

B. Other caddisflies

1. freeliving caddisfly: Rhyacophila carolina (now identified to species)
2. freeliving caddisfly: Rhyacophila nigrita (new)
3. freeliving caddisfly: Rhyacophila glaberrima (new)
4. northern case-maker: Pycnopsyche gentilis (now identified to species)
5. northern case-maker: Pycnopsyche scabripennis (now identified to species)
6. Apatania incerta: (new species in a new family of case-makers, Apataniidae)

III. Current and future directions

When I started this blog at the end of 2010, my intention was simply to report on my weekly stream visits, noting which insects I found in which streams at certain times of the year.  I also posted entries on the different families of aquatic macroinvertebrates that we encounter in our streams in central Virginia, noting the different genera, where I could make those distinctions, and adding microscope photos for those families and those genera.  My interests at the moment are these:

1. to find and identify to the level of genus -- and where I can to the level of species -- all of the different mayflies, stoneflies, and caddisflies (nymphs and larvae) that live in our streams in this part of Virginia.  I.e. I want to make our "EPT Species List for Central Virginia" as complete as I can.

2. to continually work on my photography, getting better and sharper photos of these beautiful larvae and nymphs.

3. to continue with "stream reports," adding more and more new streams to the list of places that I explore.  I have no doubt that some of our remote mountain streams contain new taxa to add to our list.

4. to carefully identify all new taxa in blog entries, using microscope photos of important morphological features.


5. to increasingly work on species level ID for those taxa that, in the past, I have only identified to the level of genus.  I was able to do that with a lot of common netspinners this summer, and at the moment I'm keen on doing it with our genus Neophylax Uenoids.

I appreciate the comments and support that I get from readers, and I hope that readers, like myself, are enjoying learning -- in detail -- about something new.

(Below: the spiny crawler mayfly, Teloganopsis deficiens, another of the new taxa discovered this year.)

Sunday, December 23, 2012

It was something about the gills: Pronggilled Mayflies -- a new genus, Leptophlebia

This entry was going to be "The Day of the Caddis" -- until I got home and realized that the pronggilled mayfly I had found at the Upper Doyles River was, for me, a new genus: Leptophlebia.  I took a lot of photos of this little nymph because the gills looked a little bit odd.  And they were.

You'll recall that almost all of the pronggilled mayflies we see are genus Paraleptophlebia.  This is one that I found at South River on 12/12.

Note that the all of the gills look the same.  Let me quote Beaty ("The Trichoptera of North Carolina," p. 40): "gill 1 similar to remaining gills in structure (usually forked with lateral tracheal branches conspicuous)."  The "forked" gills -- even the tracheation in each gill before we get to the fork -- is very clear in this photo.

Now take a close look at the gills on our nymph found this morning.

The gill on segment is small and forked: the rest are not.  The gills on segments 2-7 are "bilamellate" -- each has two thin, tracheated plates that end in a slender filament.  From Peckarsky (Freshwater Macroinvertebrates, p. 33):  Gills on segment 1 forked; remaining gills bilamellate....Leptophlebia."  In this microscope view of our nymph, you can see the simple fork on gill 1: all the rest "split" -- as it were -- into two plates which narrow down to filaments at the end.

And if we tear off one of those bilamellate gills, we see one of these.

Very cool!  I love finding new things.  Beaty lists 5 species of Leptophlebia in North Carolina.  I'll see what I can do with species ID later on, though he cautions to ID at the level of "genus".


The rest, for me, is anti-climactic, but I did find some very nice insects and got some pretty good photos.  So, off we go.

1. The flatheaded mayfly, Maccaffertium vicarium.  This species is fairly intolerant (1.5), and I've found it at this site before.  Note the dark banding on the posterior edges of the tergites and sternites.

2. Uenoid caddisfly larvae -- the rocks were covered with them.  I did not see Apataniidae at this site.  I took dorsal and ventral photos of two of the many I saw.

3. Lepidostomatid case-making larvae -- there were also a whole lot of these.  If you look closely, you can see the eyes in some of these photos.  The last photo is of a very small case that I thought was empty.  But it wasn't: you can see the little head popping out!

4. A Perlodid stonefly, Diploperla duplicata.

5. A Chloroperlid stonefly, genus Sweltsa.  Note the "hairy" wing pads, one of the traits of a Sweltsa nymph.

6. And a large winter stonefly, Taeniopteryx burksi/maura.  In the second photo you can clearly see why the coxal gills are described as "telescoping."


A final photo showing that tiny Lepidostomatid next to our pronggilled mayfly, genus Leptophlebia.

Note:   Leptophlebia has been added to the EPT lists of 9/8 and 10/1.