Giant Stonefly vs Springfly

Side-by-side species comparison

Attribute Giant Stonefly Springfly
Scientific Name Pteronarcys californica Isoperla signata
Order Plecoptera Plecoptera
Family Pteronarcyidae Perlodidae
Size 30-50 mm body 9-13 mm
Habitat Rivers & Streams Rivers & Streams
Diet Herbivores Predators
Regions North America Europe
Conservation Least Concern Least Concern

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.

Springfly

A spring-emerging stonefly of fast-flowing European streams. Nymphs are active hunters that pursue prey among streambed gravels.

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Did You Know?

Males locate females by producing species-specific vibrations that travel through the substrate.