Description
The Newly Hatched Dun – A Sitting Duck The Dun stage is the moment of truth. Unlike many other insects, the Mayfly Dun does not land on the water's surface from the air; it appears from beneath it. After the nymph reaches the surface and the shuck splits, the Dun emerges. Before it can take flight, it must sit on the water film to dry its wings. During this period, it is a "sitting duck"—completely vulnerable and the primary target for any selective trout.
Anatomical Precision in Size #12 The Mayfly Dun 2 Yellow #12 is a surgical imitation of this specific moment. In size #12, it perfectly represents the vibrant Yellow May Dun (Heptagenia sulphurea). This species is famous for its bright yellow colour and its habit of riding the current for a long time before taking off, making it a staple for fly fishers.
The J:son Advantage: The Correct "Footprint" A selective fish doesn't just see a fly; it sees a silhouette and a specific pressure on the water film.
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Born in the Surface: Our Dun is designed to sit in the surface film, mimicking an insect that has just hatched and hasn't yet gained the lift to fly.
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Realistic Silhouette: The extended body and upright wings create the exact light refraction of a real Yellow May Dun.
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Built to Float: Using advanced materials, the Dun 2 maintains its position and buoyancy even after multiple takes, ensuring you stay in the game during a heavy hatch.
Technical Recommendation: The realistic wing surface on our Size 1 and 2 flies can act as a sail during casting. To ensure a perfect, twist-free presentation, always use a J:son Swivel with this fly.