• 166 species in North America

Identification Tips:

• Body length 4-18 mm
• Head is relatively large, capsule-like, and distinct from body
• Brushes of long hairs extend forward from sides of mouth
• Segment behind head (thorax) is rounded, swollen and much wider than abdomen
• Most have short breathing tube extending from tip of abdomen
Active, swimming with by bending and unbending entire body
Usually at surface, but dive if disturbed

Life History:

• Found in almost all stillwater habitats including, lakes, ponds, steam pools, wetlands, salt marshes, temporary puddles and tree cavities
• Most species are filter bacteria, algae plankton, and organic detritus from the water column
• Use brushes on mouth parts to create current directing food
• Most breathe air through siphon at tip of abdomen
• Most lay eggs on water surface but, eggs of some species are laid above water and may remain dormant in soil for years until flooded (one such species lays in Fraser River floodplain)
• Life cycle typically completed in 7 to 10 days; many generations per year
• Adult females of many species consume blood of humans or other vertebrates

Very SensitiveSomewhat SensitiveFacultativeSomewhat TolerantVery Tolerant

Primary Information Source:
Voshell, J. Reese. 2002. A Guide to Common Freshwater Invertebrates of North America. McDonald and Woodward Publishing Company. Blacksburg, Virginia.