Enallagma anna
(River Bluet)


Order: Odonata
Suborder: Zygoptera
Order Description:
Damselflies
Family: Coenagrionidae
Family Description: Bluet

Description:
   Naiad-This is a small naiad ¾ to one inch (19 to 23 mm) long. It has the typical slender shape of immature damselflies. They range in color from green to light brown.
   Adult-This is a small damselfly 1 ¼ to 1 ½ inches (31 to 37 mm) long. The males are predominately blue on the sides of the thorax, and the upper side of the abdomen is predominantly blue, with black stripes or dots on the upper surface of most segments. Females are pale blue or tan, patterned very similarly to the males.

Range:
This species is found from Wisconsin west to southern Idaho and Montana, and south to New Mexico and southern California. In Idaho it occurs in the southern half of the state.

Habitat:
This damselfly occurs at nutrient rich streams or rivers with slow to moderate flows.

Adult Flight Season:
June 18 to August 12

Diet:
   Naiad-Naiads eat a wide variety of aquatic insects, including mosquito larvae, mayfly larvae, and other aquatic fly larvae.
   Adult-Adults eat a wide variety of small soft-bodied flying insects, such as mosquitoes, mayflies, flies and small moths. They will also pick small insects such as aphids from plants.

Ecology:
The River Bluet is usually found in nutrient-rich streams in the sagebrush deserts of the western United States.

Reproduction:
The males set up territories at choice breeding sites. After males and females mate, the male remains attached to the female (called "in tandem") as she oviposits in vegetation in streams and rivers.

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 Unpublished M. S. thesis.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 by Ean Harker, 2001.

HTML by Marty Peck, 2001.