Japanese Diving Beetle vs Cabbage Stem Weevil

Side-by-side species comparison

Attribute Japanese Diving Beetle Cabbage Stem Weevil
Scientific Name Cybister japonicus Ceutorhynchus pallidactylus
Order Coleoptera Coleoptera
Family Dytiscidae Curculionidae
Size 30-38 mm 2.5-3.5 mm
Habitat Ponds & Lakes Farmland
Diet Omnivores Herbivores
Regions Japan, Korean Peninsula Europe
Conservation Vulnerable Least Concern

Japanese Diving Beetle

A large diving beetle native to Japan, once common but now increasingly rare. It has suffered severe declines due to habitat loss and invasive species.

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Did You Know?

The American bullfrog, introduced to Japan, is a major predator of this beetle and a key driver of its decline.

Cabbage Stem Weevil

A grey weevil that mines inside brassica stems. Larvae tunnel through stems causing weakening. One of several Ceutorhynchus species affecting oilseed rape.

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Did You Know?

Larval tunneling weakens plant stems to the point where they may snap in windy conditions.