Whirligig Beetle
(
Family Gyrinidae)

These small (about half an inch) aquatic beetles swim rapidly in a circular pattern on the water surface. They feed on small invertebrates on the water surface. It is thought that the "echo" of waves generated by their swimming is detected by the antennae and used to locate prey and obstacles (like sonar). Some species have a distasteful defensive secretion for protection.

Whirligig beetles have eyes that are divided into two parts, allowing them to see above and below water when they are floating on the surface. The adult beetle breathes air and takes a bubble with it when submerging.

The larva looks rather like a small hellgrammite (Dobson fly larva) and uses dissolved oxygen in the water for respiration.

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