The Caddis Fly

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.

The following represents the process of emergence:

First Hesitation:

Usually, hours before the main hatch, some caddisflies begin appearing. The insect leaves the cocoon or shelter and will crawl or drift along the bottom currents while internal gasses fill the Papal Sheath. When sufficient buoyancy is achieved, the Caddis begins its ascent to the underside of the menicus (water film). They are easy prey at this time and fish will actively seek them out.

Second Hesitation

Just under the surface the Caddis again drifts for some distance as it struggles to break free of its Pupal Sheath and through the menicus to the waters surface.

Appearance

The larvae are grub-like in appearance and hide from predators by either building silk-like netting in front of a rocky crevice in which the larvae will seek shelter or the larvae will build a protective case by binding together small rocks, twigs, leaves, decaying organic debris and other materials that are available to the insect.

Habitat

The Caddis Fly or Sedge is able to withstand a wide variety of water conditions. However, they seem to prefer shallow, cool, well-oxygenated waters. A few species are predacious but most obtain their food from algae, diatoms, decaying plants and animal materials that form along the streambed.

Adult Caddis

Many of the emerging Caddis (Sedge) is not able to escape the pupal shuck and become a significant food source for the fish. These 'cripples' are consumed during the hatch or wash up in collecting areas where they are taken by trout well after the hatch has ended. Once the successful emergence has been made the Adults are usually taken while they are hatching and letting their wings dry, or when they return to the waters surface to either drink water or lay eggs.

Once the wings are capable of flight the insect will fly to the streamside vegetation. These insects will spend the next two weeks to two months, depending on the specific species, hanging on the underside of the streamside vegetations foliage. The insect will fly to the waters surface several times a day for water in order to prevent dehydration.

Caddis Egg Laying

Caddis Egg laying is generally accomplished in one the following methods:

First, you have to realize that these insects don't act anything like the mayfly. Once hatched and quickly air-born, these insects will hang around the streamside vegetation for one to several days. As evening approaches, the caddis adults do their mating and start fluttering around the streamside brush in anticipation of the evening hours and the time to lay their eggs. The egg laying won't begin until the sun dips below the treetops. Then and only then, will the female want to lay her eggs. The female will always perform her egg laying activities in the rapid or riffled areas of the stream.

• Caddis females dip or sprawl onto the surface of the stream. They will drag their abdomen across the surface of the water to scrape the eggs off and into the water.
  
  
• Some Caddis will crawl down into the water using the stem or foliage of streamside vegetation and even the rocks that lie along the waters edge. Once the insect has broken the water film (menicus) the female will crawl to the bottom and paste the eggs to the underside of rocks or decaying organic debris.
  
  
• The Diving Caddis will dive onto the surface film in order to break through. Once into the water the Caddis will swim to the bottom areas to perform the arduous chore of eggpasting. These female Caddis insects are coated with air bubbles while underwater. The female will return to the surface and after struggling once again with the menicus, escapes to repeat this egglaying routine in the future perhaps 2-3 times.

Remember that these insects will always do their egg laying in the rough water of rapids or riffles. When the caddis flies return to the rough water to lay eggs, they usually do their duties while flying just barely over the water's surface. The adults usually fly up-stream or across the currents to lay their eggs.

The best way to fish this insect is to use a Caddis Pupa during the actual hatch and at dusk for the egg laying activities, use a Elk Hair Caddis. The Elk Hair imitation, sizes 14, 16 & 18, must be cast up-and-across the stream. Fish the imitation down through the rough water to the head of the pool or run.

The following listing includes the 'family/genus/species' of the groups relevant to trout fishing:

Notice to all Anglers:

You now have some knowledge of Caddisflies and have learned but maybe not practiced the lessons taught. By understanding the life cycle of an insect you can use this knowledge to catch more fish. There are times during the insect's life cycle that make it attractive to feeding fish. In an area called the Riffle, Caddis will be dislodged by the current and sent downstream in the drift to waiting fish. Fish will spend as much as 75% of it's feeding time devoted to picking insects from the drift.

Remember that during the time the Caddis is trying to rise to the surface, the insect is extremely vulnerable to feeding fish. Many of the emerging caddis is not able to escape the pupal shuck and become a significant source of food for fish. These "cripples" are consumed during the hatch or wash up in collecting areas where they are taken by trout well after the hatch has ended. During the insects several trips to the water during the day for water will also provide feeding opportunities for fish.

*** Most Fly Anglers are unaware of the fact that the Caddis (Sedge) is the third most important food source for trout. As a percentage this food source represents 13% of the total food consumed. The daytime samples show that Caddis (Sedge) represents 8% of the total food consumed but the evening figures show that the same insect represents 19% of the fish's total food consumption. In terms of relative ranking this actually places the Caddis (Sedge) the second most important evening or nighttime food source. Only the fresh water shrimp are more frequently consumed during the low-light conditions of dusk.

*** The Caddis (Sedge) is the one of the last aquatic insects to start hatching in the spring and one of the first to disappear in the fall. This means that during the time they are available to the fish they are one of the primary foods. Yes, from the last week in June until the last weeks of July they are often the main food source for trout.

*** How you present your fly will be determined by the following:

When the Caddis (Sedge) is hatching, just let the fly sit on the surface of the water and wait. While waiting, let the current and winds dictate the imitations travels and always be very mindful of a free-drift and do not retrieve it. When the Sedge (Caddis) is laying eggs you will see it 'skimming' over the waters surface. When you see this skimming or traveling of Caddis (Sedge) is when you need to actually retrieve the Dry Fly (Elk Hair Caddis) at about the same speed as the actual insect. In both these cases the Dry Fly will work better if there is a breeze or slight wind as opposed to perfectly calm wind conditions.

Psilotreta hatches can be one of the most prolific hatches of the Maine summer. Even so, they are not the only kid on the block. If you fail to match the hatching caddises behavior, even if your selection is well chosen, will lead to an early evening of pure frustration. Some species can easily be confused with the Dark Blue Sedge by having a similar size, shape, color and more especially action.

The above caddis is the Spotted Caddis (Hydropsyche) is smaller than the Dark Blue Sedge. Some species of this caddis can be about the same size but the one important difference is the wings. The Spotted Caddises wings are distinctly spotted and their bodies will range from a flat brownish/yellow to cinnamon in color. The female of this species will lay her eggs (oviposit) by laying on the waters surface and undulate her body (quivering caddis) and others will actually enter the water column (diving caddis) and deposit her eggs on the bottom substrate.

To the right is the Short Horned Sedge (Glossosoma) and this species will hatch both in the early spring mornings and once again in the fall. There are also some species of this caddis that will hatch in the late spring evenings. These bugs are much smaller than the Dark Blue Sedge but are roughly the same color. The females have an unusual way of depositing their eggs. This insect will dart or run (Darting Caddis) wildly across the waters surface close to the waters riffled edges (stream-side) and then dive (Diving Caddis) beneath the surface to release her eggs. Remember the one real difference is their size, so if you are using your sized #16 or #18 Dark Blue Sedge and your having no luck, drop down to a size #22 or #24 Dark Blue Sedge and you will be imitating this much smaller caddis.

To the left is Maine's Alder Fly also widely known as the Zebra Caddis. This caddis can hatch almost as prolific as the Dark Blue but are seldom as concentrated making them often less prominent then other caddis species. The wing displays a definite black and tan pattern, i.e. The Zebra Caddis. The one other distinctive feature are the extreme lengths of this insects antennae, which are almost three times the length of this insect. This species will hatch about the same time as the smaller Dark Blue Sedge, so go up at least one hook size to imitate. You might also note that even when the hatching is roughly at the same time, they will seldom ever hatch in the same location as their cousin the Dark Blue Sedge. The females of this species will also rush to the riffles edge and dive beneath the surface to deposit their eggs.

On your right, we have the Green Caddis (Rhyacophila). This species is similar in size, shape and wing pattern to the Spotted Caddis but the obvious difference is the olive green body. This caddis will hatch sporadically from May through early September. The strange egg laying activity results in the female diving below the surface of the waters riffled edges only to release her eggs and then allow herself to become part of the biological drift.

On your immediate left is the Dark Long Horned Sedge (Ceraclea). This is another member of the family known by their extremely long antenna. On this species the antenna are about twice as long as the insect. Ceraclea caddis will hatch just after the Dark Blue Sedge and is just slightly smaller in size. Notice also that the wings have white spots and the insects profile is longer and more slender than the Dark Blue Sedge. This species will also seek the cooler fast waters of the riffles to complete their egg laying duties.

This the last of several patterns offered for your consideration. There are many fine tying manuals out there with hundreds of various caddis patterns to choose from, however, believe me that these are all you need to cover almost each stream situation that may confront you.