Japanese Diving Beetle vs Petroleum Fly

Side-by-side species comparison

Attribute Japanese Diving Beetle Petroleum Fly
Scientific Name Cybister japonicus Helaeomyia petrolei
Order Coleoptera Diptera
Family Dytiscidae Ephydridae
Size 30-38 mm 5 mm
Habitat Ponds & Lakes Underground
Diet Omnivores Omnivores
Regions Japan, Korean Peninsula North America
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.

Petroleum Fly

The only insect whose larvae develop in crude petroleum. Found in natural oil seeps in California, including the La Brea Tar Pits. Larvae eat insects trapped in the oil.

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Did You Know?

This is the only animal on Earth that develops in crude oil — a substance toxic to virtually all other life. Its larvae swim through petroleum and breathe through snorkel-like tubes.