Aeshna sitchensis
(Zigzag Darner)

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

   Naiad- This is a medium-sized naiad with a length of 1 1/4 to 1 1/2 inches (30 to 37 mm). It is long and slender like other Darner naiads. It is mottled green and brown and has a single, rear-facing spine on each side of abdominal segments seven through nine.
   Adult- This is a medium-sized dragonfly with a length of 2 1/8 to 2 1/2 inches (54 to 64 mm). The base color is olive brown to brownish black. The top of the thorax is unmarked, while each side of the thorax is marked with a pair of zig-zag stripes of yellow or light blue. The abdomen is marked with numerous blue patches.

This species is found from Alaska east to Hudson Bay south to Washington and New Hampshire. In the northern states, it is found only at high elevations. In Idaho, it occurs in the mountains of the northern and central portions of the state with the southern-most extent of its range being Alturas Lake in the Stanley Basin of central Idaho.

This dragonfly can be found at high elevation sedge marshes near lakes and streams.

Adult Flight Season:
Late June - September

   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.

Like other Darners, 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 they emerge, or change into adult dragonflies, they do so at night. This behavior probably evolved to avoid being eaten be daytime predators. Although records are sparse, adults are thought to fly from the end of June to September, and do all of their hunting while on the wing. Zig-zag Darners are able to regulate their body temperature which enables them to fly in temperatures too cold for most dragonflies.

After males and females mate, females fly singly, without the male attached, to lay their eggs in the stems and leaves of aquatic plants.

Populations are widespread, abundant, and secure.
Status: Unprotected nongame species
Global Rank: G5
State Rank: S?

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.