Japanese Dobsonfly vs Cottonwood Stag Beetle

Side-by-side species comparison

Attribute Japanese Dobsonfly Cottonwood Stag Beetle
Scientific Name Protohermes grandis Lucanus mazama
Order Megaloptera Coleoptera
Family Corydalidae Lucanidae
Size 40-60 mm body length 22-35 mm
Habitat Rivers & Streams Rivers & Streams
Diet Predators Wood Feeders
Regions East Asia, Japan Central and Southern United States
Conservation Least Concern Least Concern

Japanese Dobsonfly

A large aquatic insect known as 'hebi-tonbo' (snake dragonfly) in Japanese. The adult males have elongated, curved mandibles. Larvae called 'magotaro-mushi' are used as fishing bait.

💡

Did You Know?

Dobsonfly larvae are prized as live fishing bait in Japan and are collected from stream rocks by anglers targeting ayu (sweetfish).

Cottonwood Stag Beetle

A medium-sized North American stag beetle found near river bottoms. Males have moderately large mandibles.

💡

Did You Know?

They are most commonly found near cottonwood and willow trees along river corridors.