Adult members of the family Gyrinidae are unique in that their compound eyes are divided into separate dorsal and ventral portions, giving them a "four-eyed" appearance. This allows them to see both above and below the water at the same time. Their nickname, “whirligig beetles” was given to the adult beetles due to their behavior of zipping around in swirling motions along the surface of the water, although they are also good divers. Both the larvae and adults of this family are aquatic, typically found in quiet water of lentic or lotic habitats. The pupae are terrestrial. Both adults and larvae are engulfing predators of small invertebrates, but the adults may also be surface film scavengers. Larvae live and feed on the bottom or climb on rooted plants.
Mid-Atlantic: 4 and higher
Midwest: 3.6 - 3.7
Southeast: 5.55 - 6.3
0 = least tolerant, 10 = most tolerant
Engulfer / Predator
Lateral Gills USUALLY Absent
USUALLY 4-5-Segmented Legs
4 Posterior Hooks
5-Segmented Legs + Claws
+ Expanded Character List
Order:Larvae: Usually without lateral abdominal gills. If gills present, then 4 hooks clustered on segment 10. Thoracic legs each usually with 4 or 5 segments and with 1 or 2 claws; if without legs, head distinctly sclerotized and posterior body (thorax and abdomen) simple, without gills, hair brushes, suckers, or breathing tube. Eye spots usually present, but compound eyes absent.
Family:Legs 5-segmented plus 2 tarsal claws. Abdominal segments 1–9 with lateral gills. Abdominal segment 10 (posterior-most segment) with 4 stout hooks.
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