Damselflies are ancient insects. Fossils of the adult damselfly indicate they existed 250 million years ago! They are found on every continent in the world except Antarctica and are abundant in lakes, reservoirs, ponds, and slow-moving streams and rivers.
The immature damsel nymph is an important source of food for the trout all year. Therefore, understanding the damselfly’s life cycle and behavior is important to increase your success as a stillwater angler.
Never far from the water’s edge, the captivating dance of the colorful adult damselfly can be observed during their relatively short annual emergence during the spring and summer months.
Damselfly Description: Adult damselflies have slender, elongated abdomens and 2 pairs of wings that are held together over the body. The wings are highly veined and have hinges enabling them to fold their wings parallel to their body in a vertical position. This differentiates the damselfly from the dragonfly, whose resting wings remain flat and perpendicular to the body.
Damselflies are carnivorous and equipped with wide mouths containing strong-toothed mandibles. The bristles on their legs help trap prey such as mosquitoes, aphids, and gnats. They do not use their legs for walking, but rather to form a basket for catching prey or for perching while at rest. Each leg is tipped with a pair of claws.
The color of the adult can vary between green, blue, black, light olive, maroon, and brown, depending upon location and species. The large prominent compound eyes are found on opposite sides of the insect’s head, and the short antennae on top of the head are used for smell.
Damselfly Life Cycle: Damselflies have three life cycle stages: egg, larva, and adult. To lay her eggs, the adult damselfly can go underwater, and she is capable of being submerged for up to 30 minutes. She may crawl down vegetation, making a small incision in a stem in which to deposit her eggs. The female may also remain above the surface and deposit eggs on submerged vegetation by dipping the tip of her abdomen in the water.
Eggs hatch into nymphs after three to five weeks. Immature damselflies in the larval stage are referred to as nymphs and live among submerged plants from several months to up to four years, depending upon the species. During this time, they can undergo up to 15 instars (molts) before emergence as adults.
Damselfly nymphs are an important source of protein for trout and are available year-round. During the nymphal stage, the insect has an elongated body with small wing buds on the back of the thorax. The head is wider than the rest of the body. The abdomen terminates with three highly veined caudal gills which look like fans.
The overall body length can vary from ¼ inch to 1½ inches based on the species and age of the nymph. A fierce predator, the carnivorous damselfly nymph can be found stalking mosquito larva, mayfly nymphs, scuds, and zooplankton. Nymphs crawl or swim, propelling their bodies using an undulating movement among submerged plants and rocks and along lake bottoms searching for prey.
Like the adult stage, nymphal body coloration will vary depending on the species and habitat. Nymphal colors include brown, tan, and various shades of green.
In habitats rich with algae, you will find nymphs in various shades of green. These two damselfly nymphs were taken in the same area along the shoreline. As you can see, the one above is brown and the one below olive.
Emergence: During late May through September, damsel nymphs begin their emergence into the adult stage. After the damselfly nymph is fully grown, the nymphs rise off the lake bottom or vegetation, tucking their legs under their thorax and swimming using a sideways motion to emerge on the shore. Trout key on this and lie in ambush, intercepting and feeding on damsels.
Trout normally hunt along the shorelines early and late in the day. They prefer the safety of low light conditions or the cover of ripple to avoid predation.
However, during a damsel hatch, I have observed trout throw caution to the wind and venture into the shallow shoreline areas in a feeding frenzy, even during periods of high sun, to feast on this abundant food source.
To emerge, the nymphs climb up plant stems or up on the shoreline where they undergo the transition from nymph to adult. Once above water, they shed their nymphal skin to emerge as adults.
The nymph extends its wings and the abdomen lengthens. The skin begins to harden, and the color darkens.
After emerging from the water, the damsel’s wings take a short while to fully extend. During this time, they are especially vulnerable to predation.
Birds take advantage of this vulnerable time and gorge on the emerging damsels. In this picture you can see the birds lined up, feasting on the newly-emerged insects.
Within a few weeks after emergence, mating occurs. Mating rituals can be elaborate as the male conducts high-speed flying maneuvers in a bid to attract females. During mating, the male damselfly grasps the female behind the head with the end of his abdomen. They are seen flying in tandem, known as “wheel position.” While mating, the males may scoop out any sperm from previous suitors.
After mating, the male will remain attached to the female as she lays the eggs. This allows the male to fend off competing rivals.
Fishing Tactics and Techniques
Fish near aquatic vegetation: Cast or troll along the edge of aquatic vegetation or cast into open pockets inside the weed beds to locate and entice hungry trout. Trout search out nymphs that spend their life within the protective cover of aquatic plants.
Use a line that maintains the fly in the top few feet of the water column
Option 1: Slow intermediate sinking line – Slow intermediate sinking lines keep the fly in the top section of the water column where the emerging nymphs are located. Towards the end of the retrieve, as the fly moves upwards as the line is picked up to be recast, it often triggers a last-minute strike by fish stalking nymph in the top section of the water column. Emerging nymphs will swim 4-6” below the surface as they swim towards the shore. Try to keep the fly at the same depth.
Option 2: Floating Line – The benefit of a floating line is that it maintains the fly in the top few feet. However, the disadvantage is that it causes line shadow. Also, when the line is retrieved, it causes surface disturbance. Both will spook wary trout.
Option 3: Slow Intermediate sink tip line – This line helps keep the fly in the top few feet of water, and when retrieved, moves the fly parallel through the water, which mirrors the movement the damsel nymph. In addition, this line reduces getting your fly caught in underwater weeds. Therefore, in my experience, this line is probably the best line for fishing damsel nymphs.
During an emergence, position your pontoon or boat close to shoreline and cast towards the shore: Position yourself away from shore, but near enough so you can place your cast close to the shoreline edge. Retrieve the line slowly, incorporating definite pauses in between each retrieve. Trout will be cruising parallel to the shoreline and will see the fly in profile view. This will increase the chances of a strike.
Use a fly pattern with a marabou tail during a damselfly emergence: A marabou tail offers movement which emulates the movement of a swimming nymph. When trout are feeding, they will accept any suggestive fly pattern that has the silhouette, shape, size, and movement of what the trout are eating; an exact match of the natural is not necessary for success. The color is not as important as the movement of the fly in triggering the bite. For example, various colors of my Grizzly Bug pattern were all effective in catching fish during a damselfly emergence. I tried black, rusty brown, burnt orange, and olive, all with similar successful results.
When trolling, stop moving during the retrieve: Don’t troll and retrieve at the same time. Doing so makes the fly move too quickly. Instead, stop moving, then retrieve. Insert long pauses in between each retrieve. This will help make the fly’s movement more closely replicate the movement of a damsel nymph.
During a summer fishing trip, windy conditions interrupted the damsel hatch. I trolled close to the shoreline. I stopped my boat’s movement before executing a slow retrieve. I was rewarded with landing three trout in a row, each on a different color of my All-purpose nymph pattern. All three trout took the fly during the pause.
My next article will be on the Traveling Sedge Caddis. I fished the traveling sedge caddis hatch on a trip to Monster Lake, near Cody, Wyoming. Straightened hooks, broken 1x tippets, and trout performing amazing aerial acrobatics provided unforgettable dry fly action. Fishing the dry fly during this epic hatch was the best dry fly fishing action with big trout I have ever experienced. My next article will provide you the information you need to experience this for yourself!
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