This was originally spun as a generic nymph and in a way it is but we were pleasantly surprised to find out that it works well at times for imitating winter summer caddis pupa. In the summer you get the added bonus of this fly possibly being a drowned ant. Black caddis are greatly overlooked. This fly definitely gets the job done when those are present.
We have attempted for many years to imitate the winter summer caddis pupa sub surface. The winter warrior works in many cases but is a better representation of the larva or early pupal stage.