Whirligig beetles get their name from their erratic movements on the water surface. They are also called “apple bugs” because they release an alarm pheromone that to humans, smells like apples. Gyrinids are the only beetles that use the water surface for support. This surface tension can be lowered by the alarm pheromones, allowing the beetles to move faster through the water by surfing on the changing surface tension. Another interesting aspect to these beetles is their divided eyes. Essentially they have one set on top of the head and the other on their underside, allowing them to see above and below the water simultaneously. Adults feed on insects that fall onto the water; larvae are underwater predators.
Females lay their eggs on floating or submerged vegetation. They lay them in rows or masses and they can use the stems as well as the leaves.