Saturday, January 14, 2012

Same Old, Same Old -- With One Important Exception

The stream I went to this morning is only one to two hundred yards from the stream I went to on Thursday, and it tumbles into the Moormans from the same side of the mountain.  So, I should not be surprised that I pretty much found the very same insects on both of these trips: lots of Chloroperlid stoneflies, Peltoperlids (Roach-like stoneflies), one Isoperla similis Perlodid stonefly, and a lot of large winter stoneflies, all Taenionema atlanticum.  But today, I also found two "mixed media" Lepidostomatids (the larva in the photo above.)

Case-maker caddisfly larvae -- with the exception of Glossosomatids (Saddle-case makers) -- stay in the same case right through pupation: i.e. they do not abandon their cases and build something new as they move from one instar to the next.  But some, like the Lepidostomatid, will start off with a case of one material but switch to something new as they add on to and enlarge their cases.  A fair number of Lepidostomatids will do what this one has done -- start off with a case made of grains of sand, then switch to the more common four-sided case made out of neatly cut sections of leaves and bark.  It's like it takes them awhile to remember what a Lepido case ought to look like!  This case is a real beauty.  Here are a some additional photos.

And here is the second Lepido that I found this morning: this one was a little bit smaller.  At first, it was a little bit shy -- but it finally stuck out its head!

Lepidostomatids love the kind of stream that I went to this morning in Sugar Hollow.  As Thomas Ames notes "They roam in the slower currents of cool upland streams, near springs, and occasionally along lake shores or even in temporary streams, wherever drifting leaves settle and collect at the bottom." (Caddisflies: A Guide to Eastern Species for Anglers and Other Naturalists, 2009, p. 187.)  On their feeding habits he adds that biologists "...have described them variously as leaf-shredders or detrivores, and they are known to eat both algae and the flesh of decaying fish."  For the fly fishermen out there -- they hatch throughout the summer beginning in April and May as the "Little plain brown sedge," and Ames recommends that you wait for the adults -- not really worthwhile trying to imitate the larvae!

Some other photos from today's trip.

1. Our Isoperla similis -- another beauty (and note the "clothing hairs" on the wing pads).

2. A smaller Perlodid which, I'm pretty sure, is Isoperla namata.

3. One of many Taenionema atlanticum large winter stoneflies.

4. A gorgeous common stonefly, Eccoptura xanthenses.

5. One of many Chloroperlids (Green stoneflies).

6. And one of the Chloroperlids staring down the Eccoptura common stone.  (They're both predaceous -- could it be that they were both thinking of lunch?!)

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