Spotted Sedge - Pupae
|.............................Fly Fishing Yellowstone National Park
The Spotted Sedge (Hydropsyche species) pupae are eaten by trout during the hatch
on a regular basis. It is the easiest time for the trout to consume the pupae because
they drift in the current for a relatively long time before reaching the surface where they
emerge as adults.
When it approaches the time of year for the particular species of Hydropsyche to hatch,
the larvae will go in their shelters and seal the openings. There they will proceed to spin
a cocoon to use to pupate. It takes about two or three weeks for them to form the pupa.
At the time the hatch begins, the pupa will eat its way out by chewing a hole in the
cocoon. It will then proceed to swim to the surface to hatch. This is the time that the
trout can easily pick off the pupae. 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