Whirligig beetles[]
Arthropods (Arthropoda)----Insects (Insecta)----Beetles (Coleoptera)----Adephaga----Whirligig beetles (Gyrinidae)
On days in Spring and Summer you may see small metallic silver-black beetles swimming in quick circles on the surface of small ponds and lakes. These "Whirligig beetles" are quite hard to catch if you miss
them which makes them rapidly speed up or dive under the water. The two basic genera Gyrinus and Dineutus are fairly easy to tell apart with the Gyrinus beetles being smaller, about 5-7mm and Dineutus being around 9-13mm to the more experienced eye there is many more differences and I have learned to tell them apart just by simply looking at them. Another genus, Gyretes has beetles in the range of 3mm.
Gyrinid beetles are quite a pleasing attraction to garden ponds and are unique in the fact they have divided eyes; the top half for searching above water and the bottom half for seeing under the surface. Sometimes they huddle in groups (sometimes up to 200 beetles!) if they sense a predator nearby and these groups may consist of more than one species.
Whirligig beetle | Whirligig beetle | ||
Gyrinus sp. | Gyrinus sp. 2 | ||