We've been blessed lately with some wonderful new synthetic tying materials, from micro fibbers to antron. Polypropolene yarns are my most versatile material. It seems like almost every pattern I tie can use some sparkle yarn as a tail or wings.
Sparkle poly yarn is an especially bright and life-like material. Spinner wings, the upright wings for parachute patterns, and the trailing shuck tail of the sparkle dun are just some of the uses of this material. It is easy to see on the water, even in failing light. A little tuft mid shank on a Griffith's Gnat can really save your eyes. Fish don't care if it's there. In fact, it seems to enhance the impression of many flies. Above water it has the same translucent sheen of the natural wing. Below water it simulates the air bubbles surrounding the emerger.
The Sparkle Dun, originated by Craig Matthews of West Yellowstone, is my favorite mayfly pattern. The sparkle poly in brown or olive tied as a tail simulates the shuck of the emerging dun. This fly works! I've had fish take it over a heavy blanket of naturals right at the peak of a hatch. It can simulate the early emergent stage or the dun stage of the hatch. I once even tied it in a large #12 for a green drake hatch and it worked better than any other pattern I've tried. The Baetis pattern shown here is great for spring and fall on all our local rivers. The same sparkle poly tail can be used for other mayfly duns, just vary the body and wing color and hook size.
Hook: 16 to 22 dry fly hook, Mustad 94840 (94845 barbless).
Tail: Brown or brown-olive sparkle poly, tied length of shank or shorter.
Body: Olive-gray dubbing
Wing: Deer or elk hair tied paradun style, no hackle.