Caddisfly patterns probably take up the smallest amount of space in my fly box, but this is the one species of bug where I tend to fish the adult patterns much more frequently than the larvae/pupa patterns.
A few favorites are:
Caddisfly stages of life
The caddisfly goes through a complete metamorphosis: egg, larvae, pupa, and adult. The majority of its life is spent in the larvae stage. Some species of larvae roam freely along the river bottom but the majority of caddisfly larvae will be found encased inside a cocoon-like structure made of rocks, sand, plant material or silk.
The majority of caddisfly will hatch only during the summer months, when water temperatures reach the optimum point. The larvae crawl out of the encasement from the river bottom and slowly swim their way to the surface, pausing briefly along the way (something to take note of when retrieving your fly).
During this stage, the bugs are extra vulnerable and easy targets for hungry fish. Those that make it to the surface will hatch into their adult, flying form and connect with the opposite sex to mate.
What to watch for
Caddisfly adults can live for weeks (sometimes longer) before completing their life cycle. Fish will again target the female adults that have returned to the surface to deposit their eggs and are left exhausted on the surface of the water. You want to take note that most adult caddisfly mate at night, or at dusk. This is when the males and females will return to the surface of the water to complete the mating process.
It’s not difficult to spot this occurrence as the caddisfly adults will be flying around by the thousands, usually near dense shrubbery or large rock groupings on a bank line.