The early evening light, immediately before sunset, makes the dragonflies and damselflies hovering on the banks of Ash Creek (Lassen County CA) seem to glow. One damselfly, the river jewelwing (Calopteryx aequabilis ), needs no assistance from the long rays of the sun. This medium-sized damselfly with a metallic green/blue thorax and abdomen lives up to its name throughout the day.
A member of the pond damsel family, the river jewelwing can also be identified by its clear, veined wings, the outer third of which are black. The band of black is wider on the hindwing than on the forewing. Females are duller than the males and have white stigmas (rectangular thickened areas on the front edge near the tip) on the wings.
A native damselfly that inhabits the fast waters of wooded streams and rivers and also some lakeshores, the river jewelwing can be found throughout the northern tier of states as well as most of Canada, except at the highest latitudes. Hawaii, Puerto Rico and parts of South America also are home to river jewelwings.
River jewelwings mate shortly after they emerge in the spring. The male only remains in a reproductive state for five days on average. An unaccompanied female lays her eggs below the surface of the water on aquatic vegetation. She can stay submerged for up to a half hour while ovipositing. The nymphs, which take two to three years to develop, eat aquatic invertebrates while the adults eat small invertebrates from the foliage near the stream.