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Montana Field Guide

Montana Field Guides

Sedge Darner - Aeshna juncea

Potential Species of Concern

Global Rank: G5
State Rank: S3S5
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:


 

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State Rank Reason (see State Rank above)
The Sedge Darner is currently ranked S3S5 as a "potential species of concern" in Montana because it is potentially at risk of extirpation in the state, due to limited and/or declining numbers, range and/or habitat, even though it may be abundant in some areas.
 
General Description
The Sedge Darner is a a fairly uncommonly occurring member of the family Aeshnidae in Montana, and a potential species of concern. Darners are among the largest and fastest-flying North American dragonflies. This is a pale species, bluish areas being ampler than in most other Aeschnas. Face greenish blue, more or less overspread with brownish except on sides of the frons and facial lobes of postclypeus. Black crossbands on fronto-clypeal suture and on both front and rear margins of labrum. Black T spot above has an ill-defined front margin; its stalk is widened to its confluence with black of vertex. Top of vertical tubercle broadly yellow, occiput obscurely so. All pale stripes of thorax broad and all carinae narrowly black. Two stripes on front broadly widened laterally under crest. Between the two on each side, a short intervening half stripe terminates wide at top and tapers to a point halfway down toward spiracle. Legs brown, paler basally. Wings dull hyaline, with tawny costa and stigma. Cells in fork of radial sector and on both radial and median planates rather more numerous and irregular than is usual in Aeschna. Abdomen brown, broadly marked with blue; black on all carinae and on joinings of middle segments. Two swollen basal segments have a middorsal yellow line; sides of 2 streaked with brown and yellow, and all yellow below auricle in male. Each auricle armed with four minute teeth. Segment 3 moderately constricted. Darkening segments beyond 3 have usual spots larger than in other species, postero-dorsal one increasing markedly to rearward, covering most of depressed dorsum of 10. Mid-dorsal tubercle of 10 low and erect. The nymphs of Aeschna are among the most graceful of odonate nymphs, streamlined of body and neatly patterned in markings of green and brown that tend to run in longitudinal bands when among the green stems of water plants, in camouflage. The head is a little flattened. The legs are slender and pale, usually ornamented with rings of brown or of lighter and darker greens. The abdomen is widest in the middle and tapers gracefully to its slender tip (Needham and Westfall, 1955).

Species Range
Montana Range

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Range Comments
Sedge Darners are widespread across Alaska; Labrador; Canada: Alberta, British Columbia, Manitoba, Newfoundland, North West Territories, Ontario, Quebec, Yukon; United States: Colorado, New Hampshire, Wyoming south to Colorade and New Mexico; also from boreo-alpine regions of Europe and Asia (Needham and Westfall, 1955). Sedge Darners are usually encountered at higher latitudes or at higher elevations at lower latitudes. They are often the most commonly encountered darner species in the extreme north. Sedge Darners are circumboreal in their distribution, occurring in Europe, Eurasia, and Japan (Dunkle 2000, Paulson 2009). In Montana, found in the western Middle Rockies forested region of the state.

Summary of Observations Submitted for Montana
Number of Observations: 105

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Sedge Darners occupy ponds, lakes, pools, bays, and marshes with extensive sedge vegetation, as well as mossy fens, semipermanent ponds, ditches with emergent vegetation, and quiet stream portions in forested areas (Dunkle 2000, Paulson 2009). This species is known to hunt on and around tree trunks late into evening (Dunkle 2000).

Ecological Systems Associated with this Species
  • Details on Creation and Suggested Uses and Limitations
    How Associations Were Made
    We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
    1. Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
    4. Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
    Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.  In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.  However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if point observations were associated with that system.  Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.  The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.  If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.

    Suggested Uses and Limitations
    Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.  These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: http://mtnhp.org/requests/default.asp) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.  Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.  Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.  Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).  Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.

    Literature Cited
    • Adams, R.A.  2003.  Bats of the Rocky Mountain West; natural history, ecology, and conservation.  Boulder, CO: University Press of Colorado.  289 p.
    • Dobkin, D. S.  1992.  Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34.  Missoula, MT.
    • Foresman, K.R.  2012.  Mammals of Montana.  Second edition.  Mountain Press Publishing, Missoula, Montana.  429 pp.
    • Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998.  Montana atlas of terrestrial vertebrates.  Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT.  1302 p.
    • Hutto, R.L. and J.S. Young.  1999.  Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32.  72 p.
    • Maxell, B.A.  2000.  Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species.  Report to U.S. Forest Service Region 1.  Missoula, MT: Wildlife Biology Program, University of Montana.  161 p.
    • Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath.  2004.  Amphibians and reptiles of Montana.  Missoula, MT: Mountain Press Publishing Company. 262 p.

Food Habits
Larvae 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 very small fish and tadpoles.
Adult- The dragonfly will eat almost any soft-bodied flying insect including mosquitoes, flies, small moths, mayflies, and flying ants or termites.

Reproductive Characteristics
Male Sedge Darners are territorial and patrol, with extensive hovering, a small area of sedge along the shorelines of breeding sites. Females tend to oviposit either at the waterline or just beneath the waterline into emergent sedges and grasses, matted roots or moss (Dunkle 2000, Paulson 2009).

References
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Citation for data on this website:
Sedge Darner — Aeshna juncea.  Montana Field Guide.  .  Retrieved on , from