Sunday, December 2, 2012

Caddis day at Lickinghole Creek: Uenoids and Glossosomatids (Saddle-case makers)

(Note: It's very unusual, in my experience, to see a "live" Uenoid" caddis larva crawl this far out of its case.)

I haven't been to Lickinghole Creek in Crozet for quite awhile.  But I know that it's a pretty good stream for Uenoids, so yesterday I paid it a visit.  I was right.  Every fairly large rock I picked up had 10-15 small cases clinging to it.  But I also found quite a few Glossosomatids (Saddle-case makers), so let's have a look.

I. Uenoids.

I thought this was an interesting case, so I took quite a few photos of this particular larva -- and I'm glad that I did.  It turned out to be a new species which I think is Neophylax consimilis.  On N. consimilis, we read in Beaty ("The Trichoptera of North Carolina," p. 86):

N. consimilis -- well developed clavate ventral gills on abdominal segment 1; head and legs dark brown or with stripe or pale area...underside of head usually dark; spines on anterior pronotum needlelike.  Mostly a Mountain taxon.  Common.

I can't say this is N. consimilis for sure --  I need to get a bigger specimen (this larva was 5 mm long) to check the anterior edge of the pronotum -- but everything else is there.  We can see the "dark brown legs and head" in the picture at the top of the page, while the dark underside of the head is clear from another live photo:

For the clavate gills, we need a microscope photo:

You can also see in this photo that there is a small, orange dot in the center of the head between the eyes.  That turned out to be a small "bump" or "tubercle."  I'll have to check with Beaty to see if that can be found on this species.  But, the only other species that seems to have this "semi-blunt" tubercle on its head is N. toshioi, and N. toshioi lacks the clavate gills.  Anyway, at the moment, at tentative ID of N. consimilis.

When I went home and did my microscope work, I discovered that one of the Uenoids I kept was quite different: clearly not N. consimilis.  (Note: Beaty says that "Often 2-3 species of Neophylax will co-occur." (p. 87)  Clearly true for my findings at Lickinghole Creek.)  Look at this strange one.

Very pale coloration, and muscle scars on the back of its head and the tibiae as well.  Note that it too has clavate gills.

This one puzzled me for awhile.  But have another look at the Neophylax oligius larva photo that I posted just a few days ago.

The contours of the pale "stripe" that runs the length of the head are much the same.  So, I think this odd colored larva is an N. oligius larva that has just moved to a new instar, a larva on which the full colors have not yet developed.  (I'm checking on that with Beaty as well.)

II. Glossosomatids.

Most of the Glossos I saw had fairly large cases: this case was 12 mm long and 6 mm wide; the larva inside was about 10 mm.  And this larva is doing what Saddle-case makers commonly do when you put them into a bowl, it's climbing out of its case, something other case-makers never seem to do.    We should not be surprised.  The Glossosomatid is the only "case-maker" that abandons its case when it outgrows it and builds a new from from scratch (well, from pebbles and sand!).  But then remember -- the Glossosomatid is not a "true" case-maker: it's a "Spicipalpia" caddis, not an "Integripalpia" caddis.

Here's a dorsal view of the case of the larva in the picture above -- a real beauty -- though Glossosomatids don't seem to be meticulous builders.

I got some goods photos of a second Glosso, though in the dorsal view of the case, we see two other critters: a small Clioperla Perlodid stonefly sitting atop the case with a common netspinner larva (Ceratopsyche bronta) right in front.

And then there was this one, with a Cheumatopsyche netspinner crawling into the top of the case while the Glossosomatid exits the back!

Remember that all of our Glossosomatids are Glossosoma nigrior in terms of the species.

To close out -- a couple more photos of the C. bronta common netspinner, one that's easy to recognize because of the pattern on the head and the nota.

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