Crawling Water Beetles

Haliplidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Adephaga
Family: Haliplidae

Pronunciation

How to pronounce Haliplidae: /həˈlɪplɪdiː/

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Images

Summary

Haliplidae, or crawling water beetles, are small aquatic beetles known for their clumsy swimming style, distinctive morphology, and role in freshwater ecosystems, feeding on algae and small aquatic organisms.

Physical Characteristics

Adults are oval in shape, 1.5–5.0 mm long, yellowish to light brown with light and dark patterns and punctures on the elytra; distinctive large coxal plates on hindlegs and protruding compound eyes.

Identification Tips

Key to species available; look for oval shape, size, and coloration; presence of large hindleg coxal plates.

Habitat

Aquatic vegetation around edges of small ponds, lakes, and quiet streams; prefer standing water with abundant algae.

Distribution

Primarily Holarctic, with approximately 60 species in our area and ~240 species worldwide.

Diet

Adults are omnivorous, feeding on oligochaete worms, small crustaceans, hydrozoans, the eggs of midges, and algae; larvae exclusively feed on algae.

Life Cycle

Three instars; pupation occurs on land in a chamber constructed by the larva.

Reproduction

Eggs are deposited on the surface of aquatic plants or cavities chewed into plants by Haliplus.

Conservation Status

Hungerford's crawling water beetle (Brychius hungerfordi) is an endangered species found in Michigan and Ontario.

Ecosystem Role

As omnivores, they play a role in regulating algae and controlling populations of small aquatic animals.

Evolution

Haliplidae is believed to have evolved from terrestrial beetles; their relationship with Dytiscidae is still under examination.

Similar Taxa

Misconceptions

May be confused with predaceous diving beetles due to their aquatic habitat, but differ in swimming methods and morphology.