American Owlfly vs Japanese Alderfly

Side-by-side species comparison

Attribute American Owlfly Japanese Alderfly
Scientific Name Ululodes quadripunctatus Sialis japonica
Order Neuroptera Megaloptera
Family Ascalaphidae Sialidae
Size 20-30 mm body, 50-65 mm wingspan 15-25 mm wingspan
Habitat Meadows Rivers & Streams
Diet Predators Predators
Regions North America Japan, East Asia
Conservation Least Concern Least Concern

American Owlfly

A dragonfly-like neuropteran with split eyes and long knobbed antennae. It catches small insects on the wing during twilight flights.

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Did You Know?

Its eyes are divided into upper and lower halves, allowing it to see both above and below simultaneously.

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.