**Mayfly Species Litobrancha recurvata (Dark Green Drake)**

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Ephemeridae (Hexes and Big Drakes)

» Genus Litobrancha

» Species recurvata (Dark Green Drake)

Common Names

Match	Common Name
	Dark Green Drake
	Great Brown Spinner
	Great Dark Green Drake
	Lake Fly
	Drakefly
	Brown Bivisible
	American March Brown
	Brown Drake

This is the largest species of mayfly in North America. Sometimes it appears together with the Hexagenia limbata hatch or the Ephemera guttulata hatch, but in other places it creates excellent action on its own.

Where & When

Regions: East, Midwest
Time Of Year (?): Late May to July
Preferred Waters: Both lakes and streams

Litobrancha recurvata is abundant in fewer places than other important Ephemeridae like Hexagenia limbata or Ephemera simulans, but where it does exist it has dense populations which produce good hatches.

Emergence begins in late May in Pennsylvania. Michigan and Wisconsin follow a week or so later and peak in June. The hatch may continue through July and even into August to the north. It only lasts from three to five days on a given stretch of stream.

Hatching Behavior

Time Of Day (?): Dusk

These flies take a long time to escape their shucks (

View Full Size

Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.) in the surface film, and they are unusually prone to being stillborn (

View Full Size

This stillborn Ephemerella subvaria dun is trapped in its shuck.

Stillborn: In fly fishing, a stillborn insect is one which got stuck in its nymphal or pupal shuck during emergence and floats helplessly on the surface instead of flying away. It is a specific class of cripple, although it is sometimes used interchangeably with that term.) or crippled. Emerger and cripple (Cripple: In fly fishing, a cripple is any insect which has been injured or deformed so that it cannot escape the water. This may include stillborn emergers or fully emerged adults which have been damaged, often by wind or waves, so that they can no longer fly. Trout often favor eating crippled insects.) patterns are recommended.

Spinner Behavior

Time Of Day: Dusk

These mayflies return as spinners one to three days after hatching. Typically the duns from more than one day will return as spinners together, creating concentrated and exciting hatches. The females fall to the surface to lay their eggs.

Nymph Biology

Current Speed: Slow
Substrate: Firm silt
Environmental Tolerance: Intolerant of warm water or pollution

Caucci and Nastasi in Hatches II describe their experiments rearing these nymphs. They found that the grown nymphs, like other large burrowers, are extremely hardy, but the early nymphal stages are very sensitive to pollution or warm temperatures.

They take two to three years to mature before hatching.

Recent Discussions of Litobrancha recurvata

I agree with the nymph and emergence coments above

Posted by Beardius on Aug 1, 2008

Caucci and Nastasi's comments and other comments above are correct. They are really hardy and impressive nymphs when they near maturity. Litobrancha nymphs prefer fine silty, mucky habitats in streams. They can be abundant in mucky side channels to the main stream. Their emergence occurs over a 5-day span, with the large majority emerging within a 3-day period. Therefore, large emergences are rarely encountered. When they do occur, they can be very impressive.

From my experience collecting and rearing these critters, they have a 2-year life cycle in PA and MD. They increase tremendously in size in their second year. Emergence occurred in late May into early June about a week before that of green drakes (Ephemera guttulata).

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Jargon Defined:

Cripple: In fly fishing, a cripple is any insect which has been injured or deformed so that it cannot escape the water. This may include stillborn emergers or fully emerged adults which have been damaged, often by wind or waves, so that they can no longer fly. Trout often favor eating crippled insects.

Duns: Mayflies have two adult stages. They first emerge from the water as duns (scientifically known as the subimago stage). They then molt into the spinner (imago) stage, in which they mate and die. Sometimes the word "dun" is confusingly used to refer to a brownish gray color in fly tying materials.

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).

View Full Size

Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shucks: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.

View Full Size

This stillborn Ephemerella subvaria dun is trapped in its shuck.

Useful References:

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

Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.

Fauceglia, Ted. 2005. Mayflies . Stackpole 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.