Section 2: Lakefly Invertebrate Identification
Estimated Time For Lesson: 4 minutes
ID Notes
Whirligig beetles can be found as adults or larvae.
Whirligig beetle adults are small, shiny beetles, with orange legs, often seen spinning in circles on the surface, making them fun to watch and easy to spot!
They have 3 pairs of visible legs on both adults and larvae
Adults swim on the surface of the water, often in rapid circles when disturbed
Adult’s forewings are hardened to form two equal wing cases, which creates a straight line down their backs
Larvae are pale in colour, have white lateral gills and four very small hooks at the end of their body.
Larvae have pincer-like jaws (called mandibles) for catching prey
They can be confused with alderfly larvae and caseless caddisfly larvae.
Whirligig beetle, larvae
Photo credit: Dr Cyril Bennet MBE
Whirligig beetles are found underwater, as larvae, among aquatic plants, leaf litter, or sediment. The adults can be found on the surface, but may dive to escape predators.
They are predators feeding on other aquatic invertebrates. Adults have split eyes - one pair looks above the water, the other below, helping them see both prey and predators.
Whirligig beetle, adult