Definition for Whirligig Beetle
From Biology Forums Dictionary
Whirligig Beetle, common name for a type of water beetle that swims in irregular, but graceful curves on the surface of the water when it is disturbed. Found in temperate and tropical regions throughout the world, the whirligig beetle inhabits sheltered places along the edges of ponds and sluggish streams. Adults overwinter in leaf litter or mud, emerging in the spring to mate and to lay eggs on submerged plants. The aquatic larvae prey on other aquatic insects and mites.
The oval, somewhat flattened body of the adult whirligig beetle is usually bluish black with a metallic luster. The whirligig beetle is unique in that its compound eyes are divided into upper and lower halves. When the beetle swims on the surface of the water, the upper portion of the eye is in air and the lower portion is in water, enabling it to see both above and below the water surface. Cavities under its elytra (wing covers) trap air and allow the beetle to dive to considerable depths. The approximately 40 species of whirligig beetles found in North America are divided into two groups on the basis of their size.
Scientific Classification
Whirligig beetles are members of the family Gyrinidae, order Coleoptera. The large whirligig beetles are classified in the genus Dineutus, and the small whirligig beetles are classified in the genus Gyrinus.