AB Fish Report
Insect Encyclopedia

Green Drake

Drunella grandis

Ephemerellidae

MayflyHook #10-1212-18 mm body

Peak activity

JanFebMarAprMayJunJulAugSepOctNovDec
Green Drake — Nymph

Nymph

Large olive-brown nymph; lives in cobble riffles.

Green Drake — Adult

Adult

Large olive body, mottled gray wings.

Habitat & hatch

Found in rivers, tailwaters, and spring creeks, most commonly in riffles and runs. Bottom-dwelling nymph; emerger mid-column; adult on surface film. Often associated with gravel and cobble. Short intense hatches; duns on surface mid-morning in June–July.

Timing

Individual emergence windows typically last 3 to 14 days. Strongest surface activity occurs around midday, and the afternoon.

Sources

  • AB Fish Report synthesis from peer-reviewed Alberta and western North America literature.