Cordulia
shurtleffi
(American Emerald)
Description:
Naiad-
This is a medium-sized
naiad, or immature dragonfly, with a length of 13/16 to 1 inch (20 to 23
mm). The abdomen is rounded, giving
it a short, stocky appearance known as the sprawler form. The color is uniform
brown, with each side of the thorax marked with stripes. There are short, knobby
projections along the back, and 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 inches (43
to 50 mm). It is metallic bronze-green
and lacks any additional markings.
Range:
This species is found from
Alaska east across Canada to Labrador, extending south to California, Ohio,
and Connecticut. In Idaho, it is found in the panhandle region.
Habitat:
This dragonfly can be
found near mountain lakes, bogs, and marshes.
Adult Flight Season:
Mid May to late
June
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 stoneflies.
Ecology:
The naiads live in submerged
vegetation and woody debris on the bottom of lakes or bogs, and seem to tolerate
very cold water. They do not actively pursue prey but wait for it 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. It is one
of the first dragonfly species to emerge in the spring.
Reproduction:
Males patrol along the
water's edge searching for receptive females. 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.
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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 Unpublished M. S. thesis.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.