Japanese Alderfly vs Common Alderfly

Side-by-side species comparison

Attribute Japanese Alderfly Common Alderfly
Scientific Name Sialis japonica Sialis lutaria
Order Megaloptera Megaloptera
Family Sialidae Sialidae
Size 15-25 mm wingspan 12-16 mm
Habitat Rivers & Streams Ponds & Lakes
Diet Predators Predators
Regions Japan, East Asia Europe, Asia
Conservation Least Concern Least Concern

Japanese Alderfly

A medium-sized alderfly found in ponds and slow streams across Japan. It is one of the most common megalopterans in East Asian lowland waters.

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Did You Know?

It is one of the few megalopterans adapted to living in rice paddy fields.

Common Alderfly

A dark smoky-winged insect commonly found near still or slow-moving waters across Europe. Its aquatic larvae are predators in lake and pond sediments.

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Did You Know?

Alderfly females lay hundreds of eggs in neat rows on vegetation overhanging water, and the larvae drop into the water upon hatching.