**Mayfly Species Drunella walkeri (Large Blue-Winged Olive)**

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs)

» Genus Drunella (Blue-Winged Olives)

» Species walkeri (Large Blue-Winged Olive)

Common Names

Match	Common Name
	Large Blue-Winged Olive
	Blue-Winged Olive
	Olive Quill
	Olive Dun
	Leadwing Olive Dun
	Slate Drake

Ernest Schwiebert had this to say about the hatches of this chunky Eastern Drunella (Blue-Winged Olive) species:

An imitation is rarely required, but notes show that when it is needed it is needed badly.

See the Drunella and Drunella cornuta hatch pages for additional information.

Where & When

Regions: East, Midwest

Conflicting accounts of the emergence dates for this species abound in literature. In Matching the Hatch, Ernest Schwiebert says they emerge in late May and early June. He was probably speaking from his knowledge of Eastern rivers. The Leonards in Mayflies of Michigan Trout Streams give emergence dates of June 26-July 24 for Michigan. This species may vary between East and Midwest like other Drunella species.

Hatching Behavior

Time Of Day (?): Morning

Drunella walkeri emerges in the same manner as the rest of the Drunella genus.

Spinner Behavior

The spinner falls of this species are probably unimportant.

Nymph Biology

The nymphs are at home in fast riffles and slow backwaters alike. They are the closest in appearance to their large Western siblings the Western Green Drakes. Their stout bodies are easily distinguishable from other Eastern members of this genus.

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Jargon Defined:

Emergence: The transformation of a nymph or pupa into the adult winged stage of an insect. The term may refer to the emergence of an individual, or the daily or yearly event in which all individuals of a species emerge.

Nymphs: The juvenile, underwater stages of mayflies, stoneflies, dragonflies, and damselflies and other aquatic insects whose juvenile stages are covered by hard exoskeletons. The word can also refer to the fishing flies which imitate these creatures, in which case it is used as a blanket term for flies imitating any underwater stage of an invertebrate (except for crayfish and leeches).

Spinner: There are two winged stages of adult mayflies. They emerge from the water as duns, molt on land (usually) into their fully mature stage, spinners. As spinners, they mate, lay eggs, and die.

Useful References:

Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.

Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.

Leonard, Justin W. and Fannie A. Leonard. 1962. Mayflies of Michigan Trout Streams. Cranbrook Institute of Science.

Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.