Description
The Mayfly Dun: The Moment of Truth (The Crucial Stage)
The stage of the newly hatched adult Mayfly is called the Dun. This is arguably the most critical phase for the fly angler. Depending on surrounding circumstances such as temperature, wind, and weather, the time it takes before the Dun is able to fly away from the surface will vary.
These newly hatched Mayflies are often an easy and vulnerable target for the fish, and many will end up in Mr. Brown Trout’s stomach. When the hatching is frequent, many fish species might become selective and only feed on Duns.
Our Commitment: Perfect Imitation
Our commitment is to provide imitations of the real insect where the fly has the right shape, size, proportions, and colours, and, not least, leaves the correct print on the surface of the water.
This imitation of an adult mayfly in the Dun stage possesses all the right proportions and properties. It looks natural, feels natural, and fish will eat it.
Our Large-Winged Dun Imitation Features:
- Correct Surface Print: The imitation creates the precise silhouette on the water film that triggers the selective fish.
- Optimal Vulnerability: Designed to mimic the wing-drying, vulnerable Mayfly just before take-off.
- High Quality: Exact proportions and colours perfectly match the natural insect.
Recommendations for Best Results
We do recommend you to use a J:son Swivel for all your fly fishing. However, it is necessary to use a J:son Swivel whenever you are fishing a J:son fly in size 1 or 2 to ensure perfect presentation and minimize line twist.
The Micro-Hatch Master – J:son Mayfly Dun 5 Olive Grey (Hook #24) When the hatch consists of the absolute smallest mayflies in nature—such as micro-species of Small Dark Olives or late-season Baetis—the Olive Grey #24 is your ultimate weapon. In these technical situations, often found in low-water conditions during late summer or autumn, trout and grayling become incredibly size-sensitive. Even a size #22 can be rejected, making this #24 imitation essential for success.
Despite being tied on an incredibly small size #24 hook, J:son’s unique construction maintains the correct proportions and anatomical triggers. The subtle olive-grey foam body provides excellent buoyancy for its size, and the translucent wings create the exact "footprint" on the water that triggers a take. This is the fly to reach for when you see "invisible" rises in calm, clear water and need a micro-imitation that actually floats and performs like the real thing.