The larva are case makers. If you have spent much time in our area waters, you have seen the rectangular cases of the grannom caddis. They anchor themselves to rocks and aquatic vegetation with a fine spun silk. They will also rappel to new location using spun silk lines. The pupa will drift helpless for a distance as they struggle to escape their shuck. Once on the surface; however, the adults don’t linger long. After the emergence, you will find the adults in good numbers crawling around on the rocks and in the trees. If you’re lucky enough to be on the water, you will have them crawling all around your face, ears and neck! The females will then fly back to the water and lay on the surface or even crawl back under surface to oviposit.
Just from reading the life cycle you can see the fishing techniques are going to be many. Fishing in the middle of a Mother’s Day caddis hatch can be frustrating to say the least! Standing in your favorite stretch of river at the right time, caddis everywhere you look, and fish feeding like tomorrow might never come, and you’re getting a fish to feed every 20th cast if you’re lucky. Frustrating to say the least. I would suggest slowing down and watching how the fish are eating. It’s been my experience that if you’re seeing more of an explosive type of rise then the trout may be keying on caddis as they emerge. In this case using patterns like Lawson’s olive caddis emerger might result in more hook-ups. You could cast up stream and let the fly sink as it comes past you; tighten up your line and raise your rod tip. This will make your caddis emerger rise up through the water column as it nears the surface; be ready! These are often violent strikes! Another technique that will work is to simply drop Lawson’s caddis emerger under a dry that you can see well. A Lawson’s Hemingway caddis or a hi-vis caddis will work. Drop your emerger about a foot behind your dry fly. If you notice fish are up feeding methodically than try a spent caddis pattern. Lawson’s spent partridge caddis is tough to beat. I can almost promise you will see fish feeding in both the above mentioned styles. It’s not uncommon to see spent caddis and emerging caddis at the time on the river.