Giant Salmonfly vs Giant Stonefly

Side-by-side species comparison

Attribute Giant Salmonfly Giant Stonefly
Scientific Name Pteronarcys princeps Pteronarcys californica
Order Plecoptera Plecoptera
Family Pteronarcyidae Pteronarcyidae
Size 35-50 mm 30-50 mm body
Habitat Mountains Rivers & Streams
Diet Detritivores Herbivores
Regions North America North America
Conservation Least Concern Least Concern

Giant Salmonfly

A massive stonefly of western mountain rivers with a three-year nymphal life cycle. Nymphs feed on decomposing leaf material in cold streams.

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Did You Know?

Adults are among the largest flying insects in North America and can barely sustain flight due to their weight.

Giant Stonefly

Large aquatic insects whose nymphs require pristine, cold, oxygen-rich streams. Adults are poor fliers and stay near water. Important food source for trout.

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Did You Know?

Stonefly nymphs are so sensitive to water pollution that their presence is used by scientists as a living indicator of water quality — no stoneflies means polluted water.