Caddis Flies

Caddisfly - WikiwandFisherman probably already know how cool caddis fly larvae are, but I didn’t! At an amazing high mountain lake the other day, I saw strange critters moving around on the rocks in the clear water. I hung out over the lake for a closer look. They looked like part mollusk (with an cylindrical shell) and part beetle, and their “shell” (which I’ve now learned is called a case) was quite colorful, with greens, yellows, and some reds. Their bodies were in the cases, and their heads and thoraxes stuck out as they moved.

Northern Case Maker caddisfly | Caddis flies, Fly fishing, Insects

I spotted an empty case and fished it out of the with a stick. It was made of plant material!

I have since learned that these cases are made by many species of caddis flies in the larval stage. They are ornate and very intricate (including the one I found). Better still, the larvae will use whatever material is handy to construct these protective cases and uses silk that it excretes from salivary glands to bond the material together. The variety, materials, and construction are marvelous works of art.

The Ornate Protective Cases of Caddisfly Larvae «TwistedSifterOnce the caddis fly goes through metamorphosis, they leave the case behind. Who knew? Seriously, Google caddis flies. You’ll be amazed too.