Mayfly Lifecycle
On Vancouver Island, the heaviest emergence of mayflies generally occurs in the months of May and June, although hatches as early as March and as late as September are not uncommon. Mayflies have a simplistic lifecycle that progresses from egg to nymph to adult. The color of most nymphs tends to reflect their surroundings, and can range from reddish brown to green. Many types of mayfly nymphs can be found under rocks or hidden in vegetation. As such, rock turning can be a great way to learn about the nymphs inhabiting your local lake.
During emergence, a mayfly nymph will leave the safety of its hideout and swim to the surface to "hatch". The nymph breaks through the surface film and emerges out of its shuck to become an adult or Dun. Newly hatched Duns hold their wings and tails upright, looking like tiny sailboats while waiting for their wings to become functional. As a general rule, Duns have dull opaque wings while Spinners have wings that are shiny and translucent. Once sexually mature, mayflies mate in swarms that appear to dance up and down at the waters edge. After mating is complete, the female mayfly returns to the water to deposit her eggs and subsequently dies. Once again, trout will not pass up scavenging mayflies from the surface film.
Fishing the Emergence
When fishing a mayfly emergence, patterns that imitate both the nymph and adult can be deadly. Nymph patterns such as the Gold Ribbed Hare's Ear and the Pheasant Tail are standards in many fly boxes. Spinner patterns generally consist of a dry fly that floats flush in the surface film, tail splayed and wings held outright or "spent". In contrast, newly hatched adult Duns use surface tension to float higher on the surface with their two to three tails pointing up towards the sky. Thus, any dry fly of similar size and colour can be a good choice to try during the hatch. On Vancouver Island, the predominant colour of the lake dwelling mayfly adult is slate grey.
The featured pattern is one that I prefer as a Dun imitation. It is a simple tie and when dressed with floatant, sits in the water much like a newly hatched adult. While the pattern has no official name, I borrowed the idea from Steve Byatt and thus credit for the recipe belongs to him.
MATERIALS REQUIRED:
HOOK: #16 to #10 Dry Fly Hook
THREAD: Olive Brown or Black
TAIL: Hackle, Fine Tailing Material or White Material
BODY: Grey Dubbing
RIB: Optional Silver or Copper Tinsel
HACKLE: 1 Black and 1 Light (Ginger or Grey)
