The Caddisfly

General information: The Caddisfly or Sedge is the aquatic cousin to butterflies and moths. In fact the adult Caddis Fly or Sedge looks much like a moth except that it doesn't have the scaly wings or the siphon tube of the mouth. The common or slang term 'Sedge' originates from the fact that adult Caddis Flies can often be found clinging to the sedge grass which is found along the edge of rivers and streams. Sedge/Caddis flies have four (4) wings. The forward pair is normally a little longer than those at the rear. At rest their wings lie close along the body in an inverted V shape. Caddis/Sedge flies do not have tails but many have long antenna.

Caddis Flies go through a complete life cycle of egg, larval, pupal and the adult stage. Adult mating usually occurs on the ground or among shoreline vegetation. After fertilization the female will deposit the bright green eggs, which are usually laid in strands. The eggs sink to the bottom, hatch into larvae in about 10-12 days, and the young larvae then form their cocoon-like casings or silk netting to both protect and camouflage themselves from predators.

When the summer's time has turned to the large mayfly (Drake) and the big stonefly (Big Golden Stone) hatches, it has also become prime time for the old grand dad of caddis, the Dark Blue Sedge. These are among the largest of the caddis family and have a multiple year life cycle. Like the stones these tasty morsels are abundant to feeding fish just about year round.

Of all these summer hatches, the mayfly may well be more spectacular, but both the caddis and stones have a much more enduring quality. This is primarily due to the fact that they are available to the fish for a much longer period of time. Remember that these aquatics are very important prior to and after the major mayfly hatch activities.

The renowned and late Gary LaFontaine of Montana and Carl Richards in Michigan among others have for many years depended on these strong case makers for their early and late season successes.

These aquatics roam the bottoms of both streams and rivers in search of detritus and other foods. Some are so plentiful that fish will quickly fill their stomachs, especially during the periods when few other food forms are prominent in the water column.

Psilotreta labida (Dark Blue Sedge or DBS) is one of the few if not the only caddises believed to have a two-year life cycle. This explains why you can find them at nearly mature sizes in the late fall. The omnivorous larvae burrow into the substrate and then reappear in the spring, to hatch during the late spring or the earliest part of summer. In the mean time its cousins of the following year's generation remain hidden in the sandy or gravelly substrate.

The Dark Blue Sedge has several unique characteristics. One relates to the hardness of its case, which is a slightly curved cylinder made of sand or micro sized pebbles, secured together with the adhesive spun by all case caddises and called "silk." Most case makers also line the interior with this same material, however, the Psilotreta cases are unlined. The genus includes several species, but only two are of importance to the caddis angler (labida and frontalis). The head and legs are dark brown, however, when removed from their cases, the larva of either species is a bright, fluorescent green body covered with micro gill clusters.

These mature foragers bravely roam the surfaces of stream boulders and rocks, but their grip is tenuous at best. These caddises fare poorly in medium to strong currents, thereby swiftly adding themselves to the biological drift. For this reason, both the autumn and spring rains will create optimal angling opportunities with cased caddis imitations.

Once a part of the biological drift, the larvae will drift helplessly, and the best presentation is a dead drift at a consistent maximum depth. This technique requires the use of a strike indicator which will accomplish two very important tasks, one to observe the take and the other to assist you in mending the line without disturbing the imitation holding leader and tippet configuration.

TIP:  Did you know that when drifting along in the currents the caddis larvae will float head down, requiring your imitation to properly be tied in reverse. The head should be located at the bend of the hook and any weight added should be located at the eye of the hook so that the head floats up. This tying style has the advantage of placing the hook point where it is most likely to be intercepted by a foraging trophy and least likely to snag on the streambed. Some caddis larvae may be drifting in the mid-waters, but rarely do fish want to expend the energy required to leave their holding lies which are of course on the bottom.

As the air and water temperatures raise in early to late June, its other major hatches take over and the caddis being much less prominent will lose favor with fish as they will pursue more abundant aquatic species. The caddis will now migrate to cooler and more protected areas suitable for mid-summer emergence. The case building caddis will require from time to time constructing a larger case. Once the over-sized case is complete, the caddis larvae will seal the case and mutate within until it once again requires a larger case.

This process will continue several times during its growth from an immature larva to the last mutation into a mature pupa. This aquatic caddis will form clusters on the down-stream under-sides of stream bottom rocks. They will seal their cases and begin their last aquatic metamorphosis. Psilotreta clusters can be very dense, with cases layered on top of one another making in some cases several layers of these cases. These caddises are also site specific, with one section of the stream supporting very heavy populations and other nearby sections being completely free of any such aquatic insects. During your frequent stream analysis activities, by picking up several rocks and identifying the insect activities, you can often predict future caddis hatches that will greatly add to your future angling success.

Just as the summer activity slows and the fish have grown accustom to feasting on medium-sized mayflies like the Light Cahill (Stenacron interpunctatum), Hendrickson (Ephemerella invaria) or the larger Green Drake (Ephemere gullulata), their attention is drawn to the now active Dark Blue Sedge.

When nature calls the mature pupa will break the seal, crawl out, and begin two attempts to reach the waters surface to complete the life cycle as an air-breathing adult. As it attempts to reach the surface the emerging pupa will begin to drift downstream. In no time at all they will ascend towards the air-breathing world above by paddling with their oar-like middle pair of legs. Once at the waters surface, they will split the transparent membrane, unfold their wings and fly off very quickly.

Some species will use aquatic vegetation to emerge rather than open water where they are easy prey for the trout. Unlike many other caddis hatches, the Psilotreta caddis hatch is spread out throughout the both the hours of daylight and the evenings dark hours. This activity will not go unnoticed by area fish. A steady stream of ascending pupa will cause the fish to position themselves down-stream to intercept them.

The adult stage will last from two weeks to two months. Most Caddis or Sedge has one or two generations per year but some of the larger species can take two years to complete a generation.

The Dark Blue Sedge was named by Preston Jennings in his 1935 publication, A Book of Trout Flies.

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