Anax junius
(Common Green Darner)


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

Description:
   Naiad- This is a very large naiad with a length of 1 3/4 to 1 7/8 inches (43 to 47 mm). It is long and slender like other Darner naiads. It is mottled green and brown.
   Adult- This is a very large dragonfly with a length of 2 3/4 to 3 1/8 inches (68 to 80 mm). The thorax of the male is brownish green to yellowish green and unmarked. The abdomen is bright blue, changing to green towards the rear, and marked with black. The female is primarily yellowish green and marked with brownish black on the abdomen.

Range:
This species occurs in Canada from southern British Columbia east to Nova Scotia, and throughout the entire U.S. extending south into Mexico and Central America. In Idaho, it is found throughout the state.

Habitat:
This dragonfly can be found near weedy ponds and lakes at low elevations.

Adult Flight Season:
June - 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 stoneflies.

Ecology:
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 can be very aggressive hunters, and because of their aggressiveness they are often exposed and fall prey to predatory fish. They generally take several years to mature, and typically emerge as adults at night. This behavior probably evolved to avoid being eaten be daytime predators. Adults generally fly from June through September, and do all of their hunting while on the wing. This species is perhaps the best known of the North American migrant dragonflies. The adults that appear in Idaho in June are fully mature, having emerged earlier in the spring from ponds and lakes far to the south. They lay eggs here, and the resulting generation of naiads emerges as adults in August and migrates to the south. Here, they eventually produce a generation that will fly north in the spring.
There was an incident on the East Coast during one fall migration, where a Ruby-throated hummingbird was taken down by a dragonfly, but the dragonfly was frightened off by a group of bird watchers who saw the incident. According to the description given by the birders, the dragonfly involved was probably this species..

Reproduction:
Males establish and continually defend territories along the shores of lakes and ponds. After males and females mate, females then fly singly, without the male attached, or in tandem with the male, 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.