Aeshna umbrosa
(Shadow Darner)


Order: Odonata
Suborder: Anisoptera
Order Description:
Dragonflies
Family: Aeshnidae
Family Description: Darners

Description:
   Naiad- This is a large immature dragonfly, or naiad, with a length of 1 1/2 to 1 3/4 inches (38 to 43 mm). It is long and slender, the typical shape of immature Darners. It is mottled green and brown.
   Adult- This is a large dragonfly with a length of 2 5/8 to 3 1/8 inches (68 to 78 mm). The base color is brownish black. The top of the thorax is marked with two pairs of greenish crescent-shaped spots. Each side of the thorax is marked with two yellowish to yellowish green diagonal stripes. The abdomen is marked with bluish green spots. The male has paddle-shaped anal appendages.

Range:
This species is found from the Yukon Territories east to Hudson Bay, extending south to California, Nevada, Oklahoma, and Alabama. In Idaho, it is found throughout the state.

Habitat:
This dragonfly can be found near ditches, slow streams and ponds.

Adult Flight Season:
Late April - November

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 are active predators, and are able to swim by jet propulsion - squirting water out from the ends of their abdomens. They generally take several years to mature, and when the immature forms emerge, or change into a dragonfly, they do so at night. This behavior probably evolved to avoid being eaten be daytime predators. Adults generally fly from late April to November, and do all of their hunting while on the wing. Adult Shadow Darners are able to regulate their body temperature which enables them to fly in temperatures too cold for most dragonflies. This species in particular seems to be extremely cold tolerant. It flies at dusk and in shaded areas, and it flies later into the fall than any species other than the Yellow-legged Meadowhawk (Sympetrum vicinum).

Reproduction:
Males establish and defend territories along the shores of slow streams and ponds. After males and females mate, females fly singly, without the male attached, to lay their eggs in the stems and leaves of aquatic plants.

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.


Written by Mark Lung and Stefan Sommer, 2001
Photos by Dennis Paulson, 2001
Design/HTML by Ean Harker, 2001.