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3. How big is a Grannom larva?

fly tying time around here, as baseball goes later and later and my own amazin' Nats are out of it.

grannom larvae vary in size according to season, but from how small to how large? we're talking Pennsylvania here.

my favorite drifting grannom pattern sometimes works and sometimes doesn't, so it occurred to me that size matters.

thanks

Hi Casey-



Depending on species, a mature Brachycentrus (Grannom) larva can be expected to vary from approximately 7-13 mm in body length.

Mine here are about a 16 or 14. I tie them in 14, a bit over-sized seems to work just fine here. Since we have two species--one that emerges in spring and one in summer--the larvae are a great "search pattern"/standard. They are commonly found in trout stomachs here, case and all.

Here's my pattern:


Copper ribbed turkey tail barbs for the case. Starling neck hackle for the "legs".

And a rig I started using this year:

Shot must be kept light on the dropper, and an intact micro-barb helps hold fish. Advantage is keeping fly just up out of snags and the larval attitude is quite stable, and I like to think it looks as though it is rapelling.

Ditto, Paul. In the spring I'll carry them in #12's. My pattern shares your reversed tie design for a more accurate "head down' presentation, though the construction is a little different. The deer hair trimmed to a rectangular cross section combined with the flexable larva body are real triggers. I pull this one out when the fish are tired of all the peacock varieties (Prince Nymph, etc.) drifting by.:)

FYI - the fly is in the vise by the eye.

BTW - interesting rigging concept! Have you tried whitening the tippet to the shot? If so, did it make any difference?

No I haven't. And won't. I'm just not a believer. Larval silk is so fine I doubt there's much of a trigger there. But that's just my, off the cuff, belief.

Yeah, me too. Bought a steel marker once to give it a try, but by the time I got around to it, the pen had dried out! :)LOL. Since with your set-up only the shot is risked, one could use white tying thread I suppose. There are some Maine anglers I know that are firm believers in this concept when fishing black fly larval imitations...

can anyone translate that into hook size? of course with the way the Yankees aren't scoring, i'll get to measuring them sooner rather than later! thanks, Taxon.


a tungsten bead makes a nice dark head and now i know why it's effective. thanks, Entoman.

Hi Casey-


Here is a caddisfly larva body length to hook sizes for 7-13 mm:
7 mm = #16
9.5 mm = #14
11 mm = #12
13 mm = #10

Paul, you mention two Brachycentrus species emerging in the spring and one in the summer in your CO trout streams. I know of B. occidentalis (Mothers Day caddis) and the summer B. americanus. What is the other spring species? B. numerosus has been recently reared from larvae collected from he Republican River drainage. I haven't seen another from CO and don't know when they would emerge from this prairie drainage.

I mis-wrote that. I meant to say we have two species: one that emerges in spring and one in summer. I'll fix it to head off confusion.

Taxon, how kind! thank you very much indeed, sir! mine were on the small side, turns out--gonna fix that for sure. :-)

Please discuss this further
I'm interested in trying some different patterns this winter

Well... I've not seen this, but supposedly Brachycentrus larvae do exercise behavioral drift and when they do they assume a head down/tail up orientation. Now, I don't really try to incorporate this into my ties bc turbulence must defeat this a lot of the time in the waters I fish, so I don't see it mattering that much. Much simpler ties work too. Maybe tihs posture is more important in larger waters where drifts can be long and less turbulent?

Brachy larvae also rapel, control (shorter scale?) downstream drift with silk. I've seen them, and Hydropschids, doing this. I don't try to replicate this either.

I do believe that my ties are recognized as Brachy larvae bc of how well they are taken, along with just how common they are in stomach contents in my larger canyon streams.

My rig above does not attempt to mimic either posture or rapelling, it was just an attempt at stabilizing drift (following our discussion of fly design stability). It isn't even specific to that fly, although I can see how it could be used mimic both behaviors well.

Paul -

Good observations & advice as usual. For the benefit of others, I have the following to ad:


Regarding behavioral drift, no "supposed" about it in my experience.:) As a matter of fact, at the height of their activity, I've often had to clean them off my hooks! To head off the obvious question from readers on that statement, this happens even when the imitation is drifting suspended well off the bottom. Though it sounds amazing, on the Lower Sac there are times when a sample taken from the drift with a seine will show dozens of larvae after being in the water only a few seconds. Dead Grannom adults could be scooped up at the margins by the pound some years! That says something about the size of the population which perhaps explains (or necessitates) the need for more diurnal behavioral drift than occurs in most habitats. Anyway, the naturals drift mostly head down and I agree turbulence can certainly move them around a lot. Imitations are a different matter, though. They almost always drift hook bend down which means they are head up with traditional ties. For the same reason it's usually better for dry flies to float upright instead of on their sides (or worse on their heads), so it is for nymphs. I think it best to imitate the posture the bugs assume most of the time.


Yes, on the Grannom waters I fish that's precisely the case - they're deeper too. Since by far the most successful presentation is dead drift, the rappelling behavior of the natural isn't a consideration. I suppose a head first imitation would be better for hanging and bouncing a downstream presentation to imitate this behavior, but I don't fish them that way (mainly because of the water I fish).

Your rigging intrigues me though, as besides being good for a dead drift presentation, it would seem to make practical the simulation of the rappelling behavior when fishing upstream (when using the reverse tie). This may be especially relevant for those that fish smaller waters. Your creativity and ability to "think outside of the box" never ceases to amaze me...

Another feature of the reverse tie besides posture is the ability to tie in a little flexibility for the peeking larva. Perhaps the additional mobility is too slight to matter all that much, but I've experimented a bunch over the years and must admit the pattern I posted is the first intentional imitation of a cased Grannom that's ever worked better than a Zug Bug or Prince derivative (or even as well). This doesn't mean it's my "go to" during Grannom season though. It's more of an "ace in the hole" when the flashier impressionistic ties are boring the fish.:)

Casey -

Sorry about your Nats (not really :))... The Gigantes are still alive!!! There's some hope that Spence can be an enemy next week. :)

About hook sizes... The reason why most of us that have been around the game longer than we like to admit are reticent to give hook size in relation to bug size is because - well, the game has changed so dramatically regarding hooks. 30+ years ago we could describe critters by hook size because there were only two hooks that mattered for hatch matchers - Mustad 94840 for adults and 3906B for nymphs. Times have changed and there are now a plethora of both manufacturers and styles that make it virtually impossible to answer the question you posed. If I were you, I would measure the shank length of the hooks you prefer and compare them to the measurements that Taxon posted. I promise you will be shocked at the difference between styles and brands.

For what it's worth, I fished a reverse-tied cased grannom yesterday and did great with it on a Central, PA, stream. I tied it on a size 18 scud hook.

no, it wouldn't surprise me at all! the 238 packages of hooks lurking in the pigeon holes of my tying desk are all there because no two #14 hooks remotely resemble each other. those recipes specifying the hook brand and type used to drive me crazy. sometimes the pack will define what's inside like 2X long, heavy wire which is quite helpful. often either i find some of the hooks, or i just get used to the fact that my tye will look a little different from the picture.

off to find a suitable measuring tool. i was afraid i'd have to do that, but i suppose knowledge gained on one's own is more satisfying, rather like that gained fishing.

Casey -


Ha! Boy do I know those frustrations! Another one you hinted at is that even if the hooks are described as say #14 reg. length Dry fly, the differences between the hooks of the most popular brands with this description vary as much as 3mm or more! That really cooks my noodle! :)

You can also incorporate a small piece of mono pointing out beyond the bend of the hook with an overhand knot in it and place split shot there. This will have the fly tied regularly, but have weight to make sure it is pointing up and bouncing on the bottom with less hang ups.

Kurt, Paul, et al...:) I was just about to head off to bed when I bumped in to this...Other than Kurt's hint about my Tigers...wonderful discussion. :)

I'm in deep prep for West Yellowstone next summer and have taken out a few DVD's from my fishing clubs library. Just so happens that one was the old, "Tying and Fishing Caddisflies: With Gary La Fontaine and Friends"...Those friends being Mike Lawson and Jack Dennis for the most part.

Behavioral drift...In the vid Gary discusses this, as he did in his book. He said he uses the Cased Caddis as a searching pattern because they drift during the day as oppossed to night time drift. He then made a joke about the drift being after dark and anglers carrying all these nymph patterns for mayflies and stones and wondering aloud how they know when to set the hook after dark...He said they were working on a battery operated strike indicator with a light on it that would go off in the dark when a fish took the fly. :)

It was nice revisiting this after all these years. Gary was a rare one and truely thought outside the box. Sometimes I thought, as I watched it, that Jack & Mike where looking at him with a puzzled look on their faces...Kind of, "What will this guy say next?!" :)

Listening to him prick the bubble of some of us nit-picking tyers was wonderful. His thoughts on trout looking for "positives" in a floating fly was interesting too...Some of us worry over some details in designing our "frauds" and he would say that the trout just don't care. He was the guy that probably first discussed "triggers" etc and that creating an imitation that was perfect may be ok for the tyer and the tyer's art, but basically turned the fish off...His knock on latex versions for caddis larva made me wonder if I'm carrying them for nothing. :)

Its hard to believe he's been gone for over a decade now!!!

Spence

I just remembered something...He said that the case wasn't important, that it was just an inannimate object...When the cased caddis is drifting, at first its disoriented and when it gets its bearings it sticks its head and body out a bit from the case and it is the bit of body and legs that interest the trout...That glimpse of life and annimation that triggers the trouts response...