The range in length from 3 to 15 mm and are usually found on the surface of ponds, lakes, ad quiet streams throughout the late summer and fall. Whirligig beetles are able to skate on the water surface because of their oar-liked hind legs. They are able to beat their hind legs 60 times per second, which propels them over the surface. Their forelegs are long and slender, and enable them to gather their prey. The antennae of the Whirligig beetle have two scoop-like segments and six thick club-like segments. These unique antennae allow beetles to detect tiny waves on the water surface which forewarns of danger and lets them know where their prey are located. Their eyes are also divided into two parts which allows them to see both above and below the surface of the water.
The Whirligig beetles can also dive below the water's surface. Oxygen trapped in bubbles under their abdomen allows them to stay underwater for a long time. The bubbles serve as an underwater lung for the beetle.
There are two types of Whirligig beetles, the Large Whirligig Beetle and the Small Whirligig Beetle. The Large Whirligig Beetle is 9 to 15 mm long and often has a bronzy shine on it's black body. The adults live through the winter on plants or in the mud and then reemerge during the spring. The Small Whirligig Beetle is 3 to 7 mm long. They are yellowish brown on their sides and bottom and shiny black on top. These adults live through the winter in leaf liter near ponds and streams.
Miles Graves, Jeremy Hutcheson, Eddie Wilkerson
ENT 301, Fall 2001
