Kai's research thread/caddisfly geekout

[Kai]

I'm the first to admit I am biased in favor of molecular techniques (especially with regards to DNA), but I think that the gene based analysis is just awesome.

The Tri-corder (for species identification anyway) is not that far fetched, and not that far off.

[Kai]

I was thinking about possible characters for morphotypes yesterday, and I just started pulling vials out of museum, vials of unidentified (obviously) Cheumatopsyche larvae.

Now, Gordon (1974) did a complete revision of the Cheumatopsyche species of the Nearctic. Since then, only 3-4 new species have been described, none of them wide spread. She also did a phylogenetic revision along with the taxonomic revision, separating the species into species groups based on taxonomic characters, and providing possible routes for descent.

It was the early 20th century before anyone had attempted to do any sort of larval work with caddisflies. The name that stands out most in my mind is HH Ross. In 1944 he published a key to the Trichoptera of Illinois, a seminal work, including keys for adults and many keys for larvae as well. While he attempted species diagnosis for the larvae of several other general of hydropsychid caddisflies, he found no easy way to separate the species of Cheumatopsyche. He did, however, find some characters that were variable, the shape of the notch on the frontoclypeus, or whether it was present or absent. Mackay (1978) and Smith (1984) supplemented these characters with head length-width ratios, and further commentary on the shape of the frontoclypeal notch.

I'm guessing that the first edition of GB Wiggins' Larvae of the North American Caddisfly Genera was published in 1984 or 1985, just trying to remember. Wiggins talks about one other character in this work, the size of the pro sternal sclerites. It was not, however, until Schefter and Wiggins (1987) that the phylogenetic morphotypes started to become clear.

It turns out that the Nearctic Cheumatopsyche separate out into two distinct species groups in the adults, the Sordida Complex, and the Gracillis Complex. Gordon had noted these differences in 1974 but people did not determine the character for the two groups until 1987, where S&W determined the two complexes were obviously different in the larvae by the presence or absence of a frontoclypeal notch. They then went further to discover all these secondary setal characters. Those characters alone were used to diagnose 10 of the 14 species they had associated (adult/larval association; see previous page).

Since then, there have been a scattering of work on this project, but no one has published anything.

So, on to yesterday. I was looking at some unidentified Cheumatopsyche larvae under the scope in my office, and I started to see some interesting differences.

Theres this margin in the head of Hydropsychid larvae known as the frontoclypeal margin. It lies along the anteriodorsal length of the head on the frontoclypeus, just posterior to the labrum. In most hydropsychid genera, this margin is a straight line, but in the North American species of Cheumatopsyche (and its sister genus Potamyia, I believe), the edge is microsculpted into this ridge of notches and scallops. As I said earlier, people have taken notice of the notches, but no one to my knowlege has published anything on the scalloping. Looking more closely at a bunch of specimens, I saw that most seemed to have distinct numbers of scallops along the edge. If there was a notch in the center, some had 6 on each side of the notch, some had 4, some had 9. The individuals I found that would be considered Sordida complex (without a notch) sometimes had many many scallops, other times had only two or three on each side of a central flat stretch. Sometimes there were setae in between the scallops.

Why had no one taken a look at this before, I asked my adviser. He told me, Well, its like I said, some people are just ignorant, and no one has taken the time to look at this seriously, no one has wanted to before now.

When I start making drawings, I'll take pictures if anyone is interested.

[Vene]

 
I don't know if I have the training to understand the significance of them, but I like pictures.

[Kai]

I'm wondering if I could just stick my camera up to the eyepiece and snap some pictures.

Probably not, lens is too wide.

[Kai]

First drawing (WIP) for the morphology final. Its a large (hand and a half by two hands) drawing of Cheumatopsyche.

[Nast]

Brilliant drawing!

And those little front appendages are so cute.

[Kai]

Brilliant drawing!

And those little front appendages are so cute.

Cheumatopsyche are <3

[Telarus]

That's a surprisingly good rendering of the little bugger. 

[Kai]

That's a surprisingly good rendering of the little bugger. 

I still have to finish the gills, do some touch ups here and there, and then do a full scale reinking of the drawing adding details, but its coming along.

[Kai]

Final inking of overview.

[Vene]

Damn people who can draw better than me.

[Kai]

Damn people who can draw better than me.

Damn them, yes!

DAMN YUO FRED!!! 



In all seriousness, I'm rather pleased with the way this turned out. The rest of the drawings for this project are various parts, this one is the only full view.

[Golden Applesauce]

What are the little branching things all down the body?

[Kai]

What are the little branching things all down the body?

Membranous gills. They're outgrowths of the cuticle, creating greater surface area for gas transfer. Remember, these guys live underwater in streams and rivers.

[Kai]

The attempt with this drawing is to show the functional complex between the lower gula of the head and the femur of the prothoracic leg. The ridge/knob on the femur rubs along the ridges on the underside of the head to produce stridulations. This sound production is used territorially.

Not inked yet, obviously.