Somatochlora
albicincta
(White-ringed Emerald)
Description:
Naiad-
This is a medium-sized naiad
with a length of 13/16 to 1 inch (20 to 23.5 mm). The abdomen is rounded, giving
it a short, stocky appearance known as the sprawler form. The color is uniform
brown, and the sides of the thorax are unmarked. There is a single, rear-facing
spine on each side of abdominal segments eight and nine.
Adult-
This is a medium-sized dragonfly with
a length of 1 3/4 to 2 1/16 inches (45 to 52 mm). It is a brilliant
metallic green, with each side of the thorax marked with several wavy yellowish
stripes or dashes. Each abdominal segment is ringed with yellowish
white where it joins with the following segment. The eyes are bright green.
Range:
This species is found from
Alaska east across Canada to Labrador, extending south to Washington and New
Hampshire. In Idaho, it has been documented to occur only at the Roman Nose
lakes in Boundary County, but it probably occurs in the mountains of the northern
and central portions of the state.
Habitat:
This dragonfly can be
found near mountain lakes.
Adult Flight Season:
Late June to
September
Diet:
Naiad-
Naiads feed on a wide variety of aquatic insects, such as mosquito larvae, other
aquatic fly larvae, mayfly larvae, and freshwater shrimp. They will also eat
small fish and tadpoles.
Adult-
The dragonfly will eat almost any soft-bodied flying insect including mosquitoes,
flies, butterflies, moths, mayflies, and flying ants or termites.
Ecology:
The naiads live in submerged
vegetation and woody debris on lake bottoms. They do not actively pursue prey
but wait for it to pass by, a strategy which affords them protection from other
predators. Naiads may require several years to mature, and typically emerge
as adults at night. Although records are sparse, adults are believed to fly
from late June to September.
Reproduction:
The males establish
and defend territories along the shores of mountain lakes, and actively patrol
them in search of receptive females. Males on patrol can be very aggressive
and will chase dragonfly species much larger than themselves. After males and
females mate, the female flies singly, without the male attached, to lay her
eggs by dipping the tip of her abdomen on the surface of the water while hovering
above it.
Conservation:
Populations
are widespread, abundant, and secure.
Status: | Unprotected nongame species |
Global Rank: | G5 |
State Rank: | S? |
References:
Corbet, P. S. 1999.
Dragonflies: Behavior and Ecology of Odonata. Cornell University Press, Ithaca,
New York, USA, 829pp.
Logan, E. R. 1967. The Odonata of Idaho. Unpublished M. S. thesis. University of Idaho, Moscow, Idaho, USA, 105 pp.
Needham, J. G. and M. J. Westfall. 1955. Dragonflies of North America. University of California Press, Berkely, California, USA, 615 pp.
Paulson, D. R. 1999. Dragonflies of Washington. Seattle Audubon Society, Seattle, Washington, USA, 32 pp.
Walker, E. M. and P. S. Corbet. 1975. The Odonata of Canada and Alaska, Vol. III. University of Toronto Press, Toronto, Ontario, Canada, 307 pp.