Written by: Ted Fauceglia
Dragonfly nymphs are the Komodo dragons of the aquatic-insect world. They have a fierce disposition and a prehensile lower jaw (called the mask), which they use to capture just about any aquatic creature they can catch, including midge and mosquito larvae, mayfly nymphs, caddisfly larvae, tadpoles, and small fish. The mask features a series of hooks on its edge, which enables dragonflies to reach out and grab their prey.
Biology
Dragonflies belong to the order of insects known as Odonata. Two families in this order, Aeshnidae (darners) and Gomphidae (clubtails), are important to the fly fisher. At first glance, the nymphs of the two families look alike, but there are differences in both their appearance and in their methods of locomotion. Darners have slender bodies and are fast swimmers. They move by forcefully expelling water from the end of the abdomen. Clubtails, on the other hand, are wider, shorter, and more robust. They move by slowly crawling along the stream bottom. The two families also differ in their methods of predation: darners move about in open water and aggressively stalk their prey, while the more reclusive clubtails lie in wait and ambush their unsuspecting victims.
The name darner originates from an old wives’ tale, which warned loudmouthed, rowdy children that adult dragonflies were the “devil’s darning needles” that would sew bad kids’ lips together if they didn’t behave. The name clubtails has a less romantic origin; it simply applies to the insect’s club-like shape.
All dragonfly species have a three-stage life cycle that consists of egg, nymph, and adult. Shortly after the adult females drop their eggs, the immature nymphs emerge. Like stonefly nymphs, dragonfly nymphs have an extended life span that ranges from one to three years. Easily distinguishable from the nymphs of daintier insects, dragonfly nymphs have flattened bodies and six long, tightly bunched, spider-like legs that protrude from the upper region of the thorax. Large compound, bulbous eyes dominate the relatively small head, from which two small antennae protrude. The wingcase covers a shortened thorax, which is followed by an oversize abdomen. Unlike mayfly and stonefly nymphs, dragonfly nymphs do not have tails. Mature nymphs can reach up to an inch and a half long. Their colors vary, but most of the specimens that I’ve collected from both Eastern and Western waters have ranged from medium ginger to a very dark brown. The darkness of the wing case points to the degree of the nymph’s maturity; a darkened wing case indicates that the nymph will soon be ready to transform into a winged adult.
Preferred habitat varies with the species. Darners prefer suspended vegetation or bottom debris, while clubtails burrow into secluded niches in the bottom. I’ve found both families in just about every type of water that I’ve fished, including ponds, rivers, and all types of trout water. During the summer months, it is indeed a rare day when adult dragonflies are not circling their territories on the lookout for flying prey and intruders. On more than one occasion, I’ve watches adult dragonflies feed on emerging mayflies. Just like swallows and cedar waxwings, the dragonflies grabbed the slowly rising mayflies in midair. After catching a mayfly, a dragonfly would fly to a nearby perch, where it devoured its prey. Mosquitoes are also a favorite prey of the dragonflies, which has given rise their moniker “mosquito hawks.” The presence of the adults is a sure indication that the nymphs are in the water and are active.
Hatching takes place out of the water. When the nymphs have fully matured, they migrate to the streamside vegetation. After a brief period, the outer shell spits open and the four-winged adult slowly emerges. As soon as the crumpled wings fill with fluid, the newly emerged adult flies away.
Since dragonfly nymphs are carnivores, they hang around the most abundant sources of available prey. And since they prey on the same insects that trout eat, it puts them right in the middle of the trout’s environment and in turn makes them a key ingredient on the trout’s menu. Despite the fact that dragonfly nymphs strike fear in most of their fellow aquatic inhabitants, they are defenseless against trout. The mask is of no use against large predators. Whether the nymphs are crawling along the bottom foraging or are in the process of emerging, the trout pick them off like low-hanging fruit. Dragonfly nymphs are not so numerous as most other aquatic nymphs, but they are nonetheless an appealing food source for trout and most other insect-eating game fish. It’s easy to understand why: they’re ubiquitous; they have extended life cycles which make them available year-round, albeit in different sizes and degrees of maturity; they’re accessible; and they’re vulnerable.
TF’s Dragonfly Nymph
Thread: Ultra Denier 70 olive brown
Eyes: 30 lb. mono (burnt to shape, colored with dark brown Copic sketch
pen)
Hook: TMC 5272 sizes 12 & 10
Abdomen: mixture of brown SLF spikey dubbing & golden olive Waspi
squirrel dubbing applied with a dubbing loop and trimmed to shape
Legs: mottled brown hen hackle fibers
Wing case: brown Swiss Straw
Thorax: same as the abdomen, but applied with a dubbing noodle
Head: Ultra Denier 70 olive brown
Patterns and Tactics
Although the body shapes of the two families differ, I tie a single pattern to represent both. I suspect that there are rivers where exact patterns are necessary to match a specific species–the variety of sophisticated dragonfly patterns available suggests this–but I’ve never encountered that problem. The pattern described here has proved to be an effective all-purpose dragonfly imitation. I tie it in several sizes, in both light and dark shades-I use fox-belly fur for both shades. The pattern has worked for trout on both Western and Eastern waters, and in larger sizes it has been equally been effective on river smallmouth bass.
To imitate the movement of darner nymphs, the pattern should be fished deep and with some action. Darners move in short spurts, and to duplicate this hoppinglike motion and to get the fly on the bottom, a weighted pattern works best. Cast the pattern across stream and retrieve it by lifting and lowering the rod tip, stripping a small amount of line each time you lower the rod. When you raise the rod tip, it lifts the nymph off the bottom and brings it toward you. When you lower the rod tip, the nymph drops back to the bottom. To effectively control the action of the nymph, you’ll want to keep a tight line. This allows you to control the action of the nymph with the rod tip. To use this technique, fish a single nymph without a strike indicator.
Imitating clubtails requires less technique. Since clubtails lie in wait and rely on stealth to capture their prey, you don’t need to impart any action to the fly. A simple dead drift works best. Whether I’m fishing pools or riffles, I use unweighted patterns, and I fish two flies with a strike indicator. With this technique, the amount of weight and the length of the leader are critical factors: they both depend on the depth and speed of the water. As a rule, deeper water requires a longer leaders and more weight. Shallow, slow-moving water requires shorter leaders and less weight.
To imitate the behavior of migrating nymphs crawling toward the shoreline to emerge, I cast directly to the center of the water and bring the nymph back toward me with a very slow line twist.
Ted Fauceglia is the country’s foremost photographer of aquatic insects, and he writes the “Natural Reflections” column in each issue of American Angler. Ted is also an FFI Certified Casting Instructor, the author of Mayflies (2004), and he has provided the bug and fly-pattern photography for dozens of books.
Credit: Source link
