....................... ......Fly Fishing Yellowstone National Park
Fly Fishing Yellowstone - Spotted Sedge Pupae
Probably more Spotted Sedge (Hydropsyche species) Pupae are eaten by trout during the hatch than any other stage of life of this caddisfly. It is very easy for the trout to eat them because the pupae drift in the current for a relatively long time before they reach the surface to emerge into adults.
The larvae build shelters to reside in when they are not feeding out on the end of their silk line at their nets. To explain what goes on just before the hatch, consider that when it gets close to the time of year for Hydropsyche caddis to hatch, the larvae will go in their shelters and seal the openings. They will spin a cocoon to pupate. The pupae are formed within a couple of weeks or so. When hatch begins, the pupae eat their way out of the cocoon by chewing a hole in it. As soon as they escape the cocoon, they swim to the surface to hatch. This triggers the trout to begin feeding. They have no trouble eating the helpless pupae drifting in the current trying to reach the surface to hatch.
These caddisflies emerge in moderate to fast moving water. From the time they escape their cocoon and begin their accent to the surface they are carried downstream by the current. The pupae are in this helpless situation for some time. When they reach the surface of the water, the pupal shuck splits and the emerged adult caddisfly quickly flies away. The trout can also easily pick them off during the time they are emerging from their pupa shuck in the surface skim. These caddisflies are eaten from the time they emerge from their cocoon until they fly away to streamside vegetation far more than any other time of their life.
The emerging process usually starts late in the afternoon and continues until well into the night. The egg laying activity of the adult females from previous hatches will actually start during the time other caddisflies are emerging.
Imitating the Pupae: Start fishing an imitation of the pupa late in the afternoon. The Spotted Sedge caddisflies emerge from the riffles and runs of pocket water. They can also be found emerging from the moderate to fast moving water of smooth flowing streams. If you are catching trout on our pupa imitation, then you should continue using it until you start seeing trout eating the egg layers. This is usually very late in the afternoon, well after the sun has set. At that time you may prefer to change to our imitation of the adult.
You can fish the "Perfect Fly" Spotted Sedge Pupa using a strike indicator. I think you would probably be better off fishing without an indicator. If you are fishing smooth water, use a down and across presentation. Mend the line a time or two to help get the fly down. You may need to add weight above the fly to help get it down. When the fly gets almost directly downstream of your position, stop the downstream drift by stopping the rod. The current will bring the fly to the surface. Leave it there for a few seconds. We have had excellent success in many of the streams in Yellowstone Park using the down and across method. This method has worked very well in both the smooth water sections and the runs and riffles of the Madison, Firehole and Yellowstone Rivers