Understanding All Things PMDs (Pale Morning Duns)

Understanding the life cycles of aquatic insects is crucial for success when fly fishingPale Morning Duns also known as PMDS are a species of insect most every fly fisher will encounter. These mayflies are both delicate and abundant in many rivers and streams all across the world, providing excellent opportunities for fly fishing enthusiasts. Here, we will delve into the fascinating life cycles of Pale Morning Duns, along with hatch charts for different regions and patterns to use during each stage of their development.

 

Life Cycles of Pale Morning Duns:

Let's go over the different stages now so you can have a better understanding and help you have better success on the water.

Egg Stage:

The lifecycle of Pale Morning Duns begins when female mayflies lay their eggs on the water's surface. These eggs sink and adhere to the streambed, where they remain until they hatch. The duration of this stage can vary but typically lasts between 2-4 weeks.

 

Nymph Stage:

Once the eggs hatch, the Pale Morning Dun nymphs emerge. The nymphs will dwell in the water column and become an essential food source for trout and other fish species in the waters these insects inhabit. Here, is where they undergo several molts, shedding their exoskeletons as they grow. They have slender bodies, segmented tails, and feathery gills along their abdomen, aiding their ability to inhabit fast-flowing currents. They can spend anywhere from several months to a year in this stage, depending on environmental conditions.

Top Nymph Patterns: Pheasant Tail Nymph, Hare's Ear Nymph, PMD Split Case Nymph, Perdigon Nymph.

 

Emerger Stage:

As they near maturity, they begin to ascend to the water's surface, preparing to emerge as adult mayflies. This stage is a critical period for fly fishing, as trout and other fish eagerly target emerging insects. Pale Morning Dun emergers possess translucent wings, long tails, and split gills along their abdomen. They rest just below the surface, vulnerable but gradually gaining strength before they fully emerge.
Top Emerger Patterns: RS2 Emerger, Sparkle Dun Emerger, PMD Comparadun, PMD Soft Hackle Emerger, and Klink Hammer Emerger.

 PMD Pine Squirrel Soft Hackle Emerger Tying Video

Materials List:

• Hook: Moonlit Premium Togatta Barbless ML102 sz14-18
• Thread: Semperfli Classic Waxed 12/0 Brick Beige
• Tail: Whiting CDL Dark Dun, or Hen Saddle Fibers
• Body: Magpie Premium Wild Barred Turkey Biot PMD
• Thorax: SRF Grey Blaze Club Dub Dubbing
• Hackle: Natures Spirit Pine Squirrel Zonker Natural

Dun Stage:

During the dun stage, Pale Morning Duns will fully emerge from their nymphal shucks and rest on the water's surface. They have delicate wings with a distinct upright posture. These insects will remain on the water's surface to dry their wings and adjusting to the new environment. Trout are highly responsive to the presence of these vulnerable duns, making it an exciting time for anglers.
Top Dun Patterns: Parachute Adams, Parachute PMD,PMD Comparadun, PMD Vis A Dun.

 

Spinner Stage:

At the conclusion of their cycle, adult mayflies mate, and the females return to the water to lay eggs. The spinner stage is characterized by the distinct posture of the spent female mayflies, which lie flat on the water with their wings spread. The males, having completed their reproductive duties, also fall spent onto the water's surface. This spinner fall can result in a feeding frenzy for trout, making it an excellent opportunity for anglers.
Top Spinner Patterns: Rusty Spinner, PMD Cripple, PMD Last Chance Cripple.

 

Hatch Charts and Fishing Considerations:

Here's a general hatch chart for Pale Morning Duns in different regions:

 

Region: Western United States

Hatch Time: May to August
Best Time of Day: Mid-morning to early afternoon
Weather: Warm, sunny days
Fishing Technique: Dry fly presentations

 

Region: Eastern United States

Hatch Time: June to September
Best Time of Day: Mid-morning to early evening
Weather: Mild to warm temperatures
Fishing Technique: Dry fly presentations, nymphing