Whirligig beetle
The whirligig beetles are a family (Gyrinidae) of water beetles that swim on the surface of fresh water.
| Whirligig beetle | |
|---|---|
| |
| Gyrinus natator, 1909 illustration | |
Scientific classification 
| |
| Unrecognized taxon (fix): | Gyrinidae |
| Genera | |
|
Anagyrinus (fossil) | |
They usually swim on the surface of the water if undisturbed, though they go underwater when threatened. They swim rapidly in circles when alarmed. They have divided eyes which may allow them to see above and below water at the same time.[1]
The family includes some 700 living species worldwide, in 15 genera, plus a few fossil species. Most species are very similar in appearance, though they vary in size from 3 mm to 18 mm in length.[2] They tend to be flattened and rounded. Their shape is a good approximation to an ellipsoid, with legs and other appendages fitting closely into a streamlined surface.
Both larvae and adults are active predators. The adults carry an air bubble under their elytra, and can submerge for long periods if they want to. Mostly they move around on the surface in groups.
Whirligig Beetle Media
Illustration of Gyrinus convexiusculus, with arrows pointing to the two pairs of eyes
Whirligig beetles swarming
Black and white drawing of larval and adult stages of the whirligig beetle.
Gyrinus Head, lateral aspect showing placement of antenna and divided compound eye
Leg of Gyrinus beetle (Whirligig)
Antennae of Gyrinus beetle (Whirligig)
References
- ↑ Richards O.W.; Davies R.G. (1977). Imms' General Textbook of Entomology: Volume 1: Structure, physiology and development Volume 2: Classification and biology. Berlin: Springer. ISBN 0-412-61390-5.
- ↑ Alan Weaving; Mike Picker; Griffiths, Charles Llewellyn (2003). Field Guide to Insects of South Africa. New Holland Publishers, Ltd. ISBN 1-86872-713-0.