Pale Morning Dun vs Black Mayfly

Side-by-side species comparison

Attribute Pale Morning Dun Black Mayfly
Scientific Name Ephemerella excrucians Ephemera danica var. nigra
Order Ephemeroptera Ephemeroptera
Family Ephemerellidae Ephemeridae
Size 7-10 mm 15-25 mm body
Habitat Rivers & Streams Rivers & Streams
Diet Detritivores Omnivores
Regions North America Europe
Conservation Least Concern Least Concern

Pale Morning Dun

A small pale yellowish mayfly that hatches in large numbers on western North American streams during late spring. It is a crucial food source for trout.

💡

Did You Know?

Pale morning duns often hatch in such dense swarms that trout become highly selective, ignoring all but perfect imitations.

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.

💡

Did You Know?

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