Water Penny Beetles

Psephenidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Byrrhoidea
Family: Psephenidae

Pronunciation

How to pronounce Psephenidae: //sɛˈfɛnɪˌdaɪ//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Summary

Psephenidae, known as water penny beetles, comprise 272 aquatic beetle species found worldwide except Antarctica. Their larvae, resembling tiny pennies, live in clean, fast-flowing waters and feed on algae, making them indicators of water quality. Adults are short-lived and terrestrial, with limited feeding behavior.

Physical Characteristics

Flattened bodies, usually dark; larvae have an oval-shaped to almost circular shell, commonly copper colored, and use membrane and feathery gills for oxygen exchange.

Identification Tips

Adults and larvae can be found clinging to rocks and submerged wood in fast-flowing water, with larvae resembling tiny pennies.

Habitat

Moderate to fast current streams, clinging to rocks or the underside of logs; occasionally found in lakes.

Distribution

Worldwide, most diverse in East Asia; found in North America (Northeast and occasional in Southwest) and other continents except Antarctica.

Diet

Larvae graze on algae and are detritivorous; adults eat little to nothing and are mostly short-lived.

Life Cycle

Adults are short-lived and semivoltine; larvae overwinter and pupate under riparian substrates or in water.

Ecosystem Role

Indicate water quality; their presence signifies good-quality water; sensitive to pollution.

Misconceptions

Despite their aquatic life cycle, adults become terrestrial and do not have a significant feeding role as adults.