During late spring and early summer, the largest mayflies in our waters, Ephemera danica and Ephemera vulgata, emerge. In English, they are known as mayflies, a term that has become synonymous with all mayfly species, even those that do not hatch during this period. For many fly fishers, a newly emerged mayfly epitomizes fly fishing itself, and it’s easy to understand the fascination with these insects.
BY LARS CHRISTIAN BENTSEN
Spending most of their lives underwater as nymphs burrowing in the sediment, they live this way for up to two years before progressing to the next stage. Nymphs are rarely exposed to fish, but when it’s time to hatch, they leave the bottom, becoming a sought-after prey due to their size—they can grow up to 25 mm long. Therefore, it’s wise to include nymph imitations in your arsenal, as fish often focus on the rising nymphs even when adult mayflies are visible on the surface.
“A key to success during these hatches is using imitations that are large enough. Flies that are too small are often ignored”.
At the surface, the nymph hangs suspended while the adult mayfly emerges by breaking through its exoskeleton. Depending on the weather and temperature, this process can be short if it’s sunny and warm, or longer if it’s cooler and more humid. Once their wings are dry, the adult mayflies fly to land and undergo another transformation, shedding their initial exoskeleton and becoming spinners. In this stage, they swarm to find a mate. After mating, the males die, while the females return to the water to lay eggs, after which they also perish. The spent females provide an easy meal for hungry fish.
Timing the hatching of these large mayflies is a dream for many anglers. Their size tempts even large fish to rise and feast on emerging or dying mayflies, often creating loud splashes. However, during mass hatches, fish can ignore imitations amidst the abundance of real insects, leaving anglers empty-handed despite waters teeming with rising fish.
Ephemera Danica vs. Ephemera Vulgata
Ephemera danica, also known as the Green Drake, is the larger of the two species. It thrives in running waters with sandy bottoms crucial for the nymph’s survival. These mayflies hatch from May through July or August, depending on location. In northern Sweden, hatching may not occur until mid to late summer.
The smaller Ephemera vulgata, or the Lake Mayfly, prefers still or very slow-moving waters. Both species can coexist in the same rivers, with danica favoring flowing stretches and vulgata inhabiting backwaters or slower sections. Besides their size difference, the two species can be distinguished by their coloration: danica is lighter, with yellow and olive hues, while vulgata is darker, with shades of brown and gray.
Fly Tying and Presentation Tips
A key to success during these hatches is using imitations that are large enough. Flies that are too small are often ignored. A challenge with such large dry flies is that their size can twist a fine tippet. It’s essential to use materials that float well but are not too bulky, minimizing tippet twisting.
Renowned fly fisher and fly tyer Lars Christian Bendsen has designed a simple yet effective imitation, the LCB Danica. This pattern is easy to cast without tangling the tippet and can be adapted in color and size to mimic both species.
LCB Danica
Hook: Ahrex FW538/539, size 8
Thread: Olive UNI 8/0
Tail: 3 strands Faux Bucktail (or Moose Mane), black
Body: Fly Rite Poly Seal, Tan
Ribbing: Black tying thread
Thorax: Fly Rite #32 Rusty Olive
Hackle: Whiting Coq de Leon hen, dyed yellow
Head: Fly Rite #32 Rusty Olive
Wing: White and olive blended polygarn
LCB Vulgata
To tie an Ephemera vulgata imitation, use the same pattern with slight modifications:
Hook: Ahrex FW538/539, size 10
Thread: Olive UNI 8/0
Tail: 3 strands Faux Bucktail (or Moose Mane), black
Body: Fly Rite #34 Quill Gordon/Brown Drake Yellow
Ribbing: Black tying thread
Thorax: Fly Rite #39 Medium Dun Brown
Hackle: Whiting Coq de Leon hen, dyed brown
Head: Fly Rite #39 Medium Dun Brown
Wing: Brown, gray, and olive poly yarn
This adaptable and straightforward pattern ensures anglers are prepared to imitate these iconic mayflies successfully.
