Northern Stonefly vs Mountain Dance Fly

Side-by-side species comparison

Attribute Northern Stonefly Mountain Dance Fly
Scientific Name Nemoura arctica Empis pennipes
Order Plecoptera Diptera
Family Nemouridae Empididae
Size 6-10 mm 5-8 mm body length
Habitat Rivers & Streams Rivers & Streams
Diet Herbivores Predators
Regions Arctic Scandinavia, Finland, northern Russia, Iceland, Arctic Canada Europe, Alps, Scandinavia
Conservation Least Concern Least Concern

Northern Stonefly

A small, dark brown stonefly with two long cerci at the tip of the abdomen. Adults hold their wings flat over the body. Nymphs develop in cold, well-oxygenated streams and are indicators of clean water.

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Did You Know?

Stonefly nymphs are so sensitive to pollution that their presence in a stream is used as an indicator of excellent water quality.

Mountain Dance Fly

A predatory fly with feathery leg fringes used in aerial mating displays. Males offer prey gifts wrapped in silk to females during courtship.

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Did You Know?

Males with the most elaborate feathered legs are preferred by females during mating swarms.