The ebony jewelwing (Calopteryx maculata) is a species of broad-winged damselfly. It is one of about 170 species of Odonata found in New England, the Mid-Atlantic states, and southeastern Canada. Other common names include black-winged damselfly.

Identification

The head is iridescent blue-green. The thorax is black with strong iridescent blue-green coloration dorsally and on the sides. Males lack a pterostigma. Older, mature males have solid black wings, while wings in teneral individuals are lighter and brown in color. Wings of females are usually paler, becoming progressively darker apically with a conspicuous white pterost igma (enclosing numerous cells ) that is distinctively widened at middle. Length of wings is about three times their greatest width. The abdomen is iridescent blue-green dorsally, black ventrally, except for a white (males ) or brown (females ) area on the posterior of sterna 8 and segments 9 and 10.

Total length: 37-57 mm; abdomen: 30-47 mm; hindwing: 25-37 mm.

Similar Species

Smoky Rubyspot (Hetaerina titia ) is the only other damselfly that may have completely dark wings. It lacks the blue-green iridescence on the body and the wings are only about a fifth as wide as long. In Sparkling Jewelwing (C. dimidiata ) only the apical fourth of the wings are black.

Habitat

Small, slow moving, canopy covered streams and occasionally exposed streams and rivulets.

Prey of this species includes the tiger mosquito, giant willow aphid, fungus gnats, crane flies, large diving beetles, eastern dobsonfly, water fleas, green darner, aquatic oligochaetes, caddisflies, rotifers, copepods, amphipods, dogwood borer, six-spotted tiger beetle, freshwater triclads, and green hydra.

Predators of this damselfly include birds such as the great crested flycatcher, American robin, mallard, red-winged blackbird, and blue jay, reptiles and amphibians such as the eastern painted turtle, common snapping turtle, and southern leopard frog, fish such as the bluegill, largemouth bass, yellow perch, creek chub, channel catfish, common carp, and northern hogsucker, mammals such as the big brown bat, and insects such as the green darner, large diving beetles, eastern dobsonfly, and common water strider.

The damselfly shelters among various plants and algaes in its habitat, including green algae, yellow water lily, hydrilla, lizard's tail, pickerelweed, common cattail, upright sedge, common bladderwort, common duckweed, black willow, orange jewelweed, spotted Joe-pye weed, poison ivy, wild grape, sassafras, common greenbrier, and buttonbush.

This species ranks among the most studied of damselflies in North America. Nymphs are local in occurrence and restricted to slow creeks and quiet areas of running streams. The primary factors affecting their distribution within streams are rate of flow, depth of water and type of vegetation present while, adults occur along a wide variety of stream-riverine conditions and often disperse well away from water. Males will vigorously compete among themselves for territories with submergent vegetation, the prime egg-laying habitat for females. Males attract females with a "cross display," where the male faces the female with his hindwings deflected downward at right angles to his body, and the forewings and abdomen are raised, revealing the ventral pale area of the abdomen. The major ity of mating and egg laying occurs in the early afternoon and a single male may guard multiple females, resulting in sometimes large congregations. Females will lay their eggs in submergent vegetation for 10 to 120 minutes and usually don't submerge themselves. The displays and behaviors of northern and southern populations may differ. For a summary of these behaviors the reader is directed to Dunkle (1990). Female Ebony Jewelwing has been reported to use her ovipositor to steady herself on a leaf while feeding on a mayfly.