Pale Evening Dun vs Trico Mayfly

Side-by-side species comparison

Attribute Pale Evening Dun Trico Mayfly
Scientific Name Heptagenia adaequata Tricorythodes stygiatus
Order Ephemeroptera Ephemeroptera
Family Heptageniidae Leptohyphidae
Size 8-12 mm 3-6 mm
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Detritivores
Regions Europe North America
Conservation Least Concern Least Concern

Pale Evening Dun

A flat-bodied mayfly whose nymphs press tightly against rocks in swift currents. Adults emerge at dusk during summer months.

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Did You Know?

Its extremely flattened body allows it to resist currents that would sweep away most other insects.

Trico Mayfly

A tiny mayfly that forms enormous morning spinner falls over calm streams and rivers. Males have distinctive white bodies with black thoraxes.

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Did You Know?

Trico spinner falls create such dense blankets of spent mayflies on the water surface that trout gorge themselves to satiation.