merely quell some of these misunderstandings and to possibly persuade those of you that look down upon caddisflies to alter this view slightly, through the offering of some specific trout producing techniques, patterns, and useful dribble I have picked up along the way as I grew stronger in my belief that caddisflies rank well above mayflies in importance.
Larva Behavior
Caddisflies consist of approximately 1,300 known species across all of North America, stretching their diversity throughout various locations and habitats such as marshlands, rivers, streams, and ponds. The majority of the specimens in this order spend their larva lifecycle clinging to and feeding from within the crevices found amongst rocks, gravel and submerged logs in areas of fast-flowing riffles or vegetation substrates of ponds. If there was ever a greater distinction that separates one species from the next, it is found in the bottom-dwelling traits of caddisfly larvae.
The first trait is the naturally camouflaging, case-building families such as the Brachycentridae (Apple Caddis and Grannoms), which harbor the anxiously awaited Brachycentrus occidentalis, or as mid-west and western anglers fondly refer to this prolific hatch, the Mother’s Day Caddis. This particular species build an intricate tubular or rectangular shaped home where it spends much of its lifecycle prior to pupation. The bright-green, soft-bodied larvae construct their case using a spider like silk combined with various materials dependent upon available underwater debris such as twigs and plant matter.
Other species build their cases utilizing grains of sand and tiny pebbles from the surrounding habitat, while others are known for hollowing out the inside of plant stems. The finished shelter serves as a sort of mobile command post for the larva and protection from other predatory insects, with most caddisflies spending much of their life rebuilding and maintaining the structure to accommodate for its growth. Caddisfly larvae are unencumbered by the added weight of the case, and are known for carrying the case along as it scourers the bottom in search for food.
The second defining trait is found in one of the most abundantly important caddisfly genus in the family Hydropsychidae. The net spinners of the caddisfly genus Hydropsyche (Spotted Sedge) build intricate spider-web like contraptions in crevices of rocks and logs. However, these silk webs are not designed with sheltering defenses in mind upon completion. These serve as hunting traps. Such species like the invaluable Midwest and Western Hydropsyche occidentalis and Hydropsyche californica use the web to ensnare microscopic plankton to feast upon. Some larvae of the net-spinning genera build upwards of 2 to 3 working webs at a time, and crawl along the bottom of their habitat to maintain each in working order.
There also exists an extremely important—for both angler and trout—non-case building or net-spinning species of caddisfly. The robust, bright-neon green, free-range caddisfly family Rhyacophilidea (Green Sedge) spend their lifecycle as a larva, crawling and clinging to rocks and other submerged structures in predominately fast moving riffle sections of rivers. The 100-plus species found in the genera of Green Sedges are largely predacious and subsist solely on insect larvae, including other caddisflies. Their importance is found in their biological need for oxygen rich waters because of their lack of gills, and the exposure to fast currents this life sustaining need demands. This, along with the behavioral drift which I will cover here shortly, creates prime opportunities for feeding trout. But, before I get to the behavioral drift and lastly how to target the three-stage-emergence of caddisflies, I want to take the time to point out one of the many moments that is the awesomeness of this insect order.