The unfortunate sowbug has no winged phase. Summer days might fill the riverside air with dancing mayflies, floating midges, the zigging and zagging of caddis, and even low buzz of stoneflies–freed at last, however momentarily, from their aquatic homes–but the three species of Asellidae remain water-bound; hiding in stream bottom crevices while munching river leftovers, crumbs from the plates of others.
It's somewhat sad, as trout stream drama goes. But for the fly fisher who knows what the trout know about the sowbug, the 3/8-inch to 1-inch long crustacean is dinner. A close relative of its cousin crustaceans the scud and the crayfish, the sowbug is a tiny, power packed bit of protein for piscatorial predators.
Along with such far-off neighbors as the crab, perhaps even the eel or catfish, if one reaches a bit, the sowbug is a detritivore, in formal entomological terms. Colorado State's Dr. Boris Kondratieff, professor of entomology, tells me that sowbugs are "shredder-detritivores." For most of us, that means they eat discarded organic material, or darned near anything in the river that doesn't move, especially those items that aren't going to move anymore at all.
Asellidae most famously are part of the forage base in Montana's Bighorn River and the White River in Arkansas, but they can be found in many, many trout streams. It's easiest to find them by looking in stream bottom vegetation. The sowbug reminds one of the scud, as both have shellbacks and tiny, shiny legs. But Asellidae do not swim, and are flat rather than having the rounded, torpedo shape of the scud. Colors are most often brownish to grey to light olive.
With its somewhat different lifestyle, the sowbug has spawned some colorfully named flies. The most well known is the Ray Charles. Effective throughout the Rockies, it's best fished in sizes 14-18. It's a simple tie of ostrich herl, pearl flashing for the shellback, and a head of red thread, and Charlie keeps them in the shop. A "Google" of the fly's name will produce tying instructions.
The prize winning name for a sowbug fly has to be the one from Arkansas. Locally tied, locally named, the webby hackled imitation most often used on the White River is called the Red Ass. If I could think of something to add to that, I would.
