• 56 species in North America
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Gyrinidae

Identification Tips:

• Elongated , narrow, white or cream coloured body
• 10 pair of stout projections from abdomen
• 4 hooks at tip of abdomen
• 3 pair of segmented legs, each ending in two claws
• 6-30 mm

Life History:

• Common near shore in streams, ponds and lakes

• Adults typically swim quickly in erratic patterns on surface, often in groups
• Dive and swim underwater when disturbed; breathe from air bubble trapped under wings
• Each eye is divided with half focused above water and half below
• Consume organic material or small invertebrates on water surface
• Not eaten by fish due to foul tasting chemical secretion

• Larvae typically climb and swim among aquatic plants
• Prey on worms, midge larvae, and other small invertebrates
• Pupate in small domes constructed of leaves or debris on ground, rocks, or on vegetation above water line

Very Sensitive Somewhat Sensitive Facultative Somewhat Tolerant Very Tolerant

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