Black Mayfly vs Western Ameletid Mayfly

Side-by-side species comparison

Attribute Black Mayfly Western Ameletid Mayfly
Scientific Name Ephemera danica var. nigra Ameletus cooki
Order Ephemeroptera Ephemeroptera
Family Ephemeridae Ameletidae
Size 15-25 mm body 8-12 mm
Habitat Rivers & Streams Mountains
Diet Omnivores Omnivores
Regions Europe North America
Conservation Least Concern Least Concern

Black Mayfly

A dark color variant of the common Green Drake mayfly found in some European populations. The dark form is more prevalent in upland, acidic waters. Important for trout feeding.

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Did You Know?

The dark form predominates in acidic upland streams while the typical yellow form prefers alkaline lowland rivers.

Western Ameletid Mayfly

A streamlined mayfly found in cold mountain streams of the Pacific Northwest. Nymphs are agile swimmers that dart between cobbles in riffles.

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Did You Know?

Nymphs are strong enough swimmers to move upstream against moderate currents.