Stream Bluet Damselfly Habitats: Greenish Body, V- or W-Marked Abdomen

Summary: North American stream bluet damselfly habitats from Canada to Mexico get greenish heads and thoraxes, pale eyespots and bars and V- or W-marked abdomens.

stream bluet damselfly (Enallagma exsulans); Patuxent National Wildlife Refuge, near Laurel, Anne Arundel County, southern Maryland; June 10, 2012: Judy Gallagher (judygva), CC BY 2.0, via Flickr

North American stream bluet damselfly habitats assuage arborists, master gardeners, master naturalists and tree stewards with water-filled distribution ranges from Nova Scotia through Mexico, Ontario, Canada, the Great Plains and everything in-between.

Stream bluets bear their common name for stream habitats and from blue colors and the scientific name Enallagma exsulans (together [in ovipositing] damselfly [that is] exiled. Common names crystallize the consensus of scientific committees convened by the Dragonfly Society of the Americas, whose quarterly journal Argia contains advice, events, research and reviews. Descriptions in 1861 by Hermann August Hagen (May 30, 1817-Nov. 9, 1893), nephew-in-law of astronomer Friedrich Wilhelm Bessel (July 22, 1784-March 17, 1846), drive scientific designations.

Stream bluet damselfly life cycles expect clean or degraded, moderate- or slow-flowing, large- or medium-sized lakes, rivers and streams with dense waterside vegetation, especially of water-willow.

April through October function as maximum, most southerly flight seasons even though June through August furnish wildlife mapping opportunities in all North American stream bluet niches.

Male stream bluets go later in the afternoon to foraging and pre-mating perches on low-lying shoot tips that give lake, upriver and upstream access and views. They hover a foot (30.48 centimeters) over lake, pool, river and stream surfaces for hours before, and subsequent to, hunkering on emergent or waterside herbaceous stems. Black-spurred, black-striped pale legs and projectable, retractable lower lips immobilize low-flying, low-lying, flushed or opportunistic prey since stream bluets imitate gleaner pond damsels, not sallying dancers.

Ants, biting midges, ducks, falcons, fish, flycatchers, frogs, grebes, lizards, robber flies, spiders, turtles and water beetles and mites jeopardize North American stream bluet damselfly habitats.

Immature stream bluets keep dull, pale colors whereas adults know black and blue colors as males and blue or green with black and brown as females.

Incomplete metamorphosis links rod-shaped eggs laid above-water on emergent, or below-water on submergent, vegetation, multi-molting, nonflying larvae, naiads or nymphs and molted, shiny-winged, soft-bodied, weak-flying tenerals. Tenerals as emerged adults from the immature stage's last molt manage permanent colors and sexual maturation before 55- to 119-minute matings and 15- to 31-minute ovipositing. Bluet members of the Coenagrionidae pond damsel family need aphids, beetles, borers, caddisflies, copepods, crane flies, dobsonflies, gnats, leafhoppers, mosquitoes, rotifers, scuds, water fleas and worms.

North American stream bluet damselfly habitats offer season-coldest temperatures, northward to southward, from minus 45 to 20 degrees Fahrenheit (minus 42.77 to minus 6.66 degrees Celsius).

Beech, bellflower, birch, bladderwort, cattail, daisy, grass, greenbrier, heath, laurel, madder, maple, nettle, olive, pepperbush, pine, pondweed, rush, sedge, water-lily and willow families promote stream bluets.

Black-capped blue eyes, pale blue- or green-, single-striped dark heads, black-brown-striped thoraxes and pale-tipped black abdomens with one W-patterned pale terminal segment quicken adult female identifications. Males reveal black-capped turquoise eyes, blue-, narrow-striped black heads, blue-green thoraxes with black-, wide-striped shoulders and upper-sides and blue-green-sided, blue-green-tipped abdomens with one V-patterned terminal segment. Adults show off 1.22- to 1.46-inch (31- to 37-millimeter) head-body lengths, 0.95- to 1.18-inch (24- to 30-millimeter) abdomens and 0.67- to 0.83-inch (17- to 21-millimeter) hindwings.

Green-tinged blue colors, pale eyespots near pale bars and V- or W-patterned abdomens tell stream bluets from other damselflies in North American stream bluet damselfly habitats.

female stream bluet damselfly (left) and male stream blue damselfly (right); Rock Creek Park, Washington DC; June 4, 2016: Katja Schulz, CC BY 2.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

stream bluet damselfly (Enallagma exsulans); Patuxent National Wildlife Refuge, near Laurel, Anne Arundel County, southern Maryland; June 10, 2012: Judy Gallagher (judygva), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/52450054@N04/7359885782/

female stream bluet damselfly (left) and male stream blue damselfly (right); Rock Creek Park, Washington DC; June 4, 2016: Katja Schulz, CC BY 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Stream_Bluets_Mating_-_Flickr_-_treegrow_(1).jpg

For further information:

Abbott, John C. Dragonflies and Damselflies of Texas and the South-Central United States: Texas, Louisiana, Arkansas, Oklahoma and New Mexico. Princeton NJ; Oxford UK: Princeton University Press, 2005.

Beaton, Giff. Dragonflies & Damselflies of Georgia and the Southeast. Athens GA; London UK: University of Georgia Press, 2007.

Berger, Cynthia. Dragonflies. Mechanicsburg PA: Stackpole Books: Wild Guide, 2004.

Bright, Ethan. "Enallagma exsulans (Hagen, 1861: 82 -- as Agrion) -- Stream Bluet." Aquatic Insects of Michigan > Odonata (Dragon- and Damselflies) of Michigan > Zygoptera, Selys, 1854 > Coenagrionidae, Kirby, 1890 (Pond Damselflies) > Enallagma Selys, 1875 (Bluets).
Available @ http://www.aquaticinsects.org/sp/Odonata/sp_oom.html

"Enallagma exsulans." James Cook University-Medusa: The Odonata - Dragonflies and Damselflies > Zygoptera > Coenagrionidae > Enallagma.
Available via James Cook University-Medusa @ https://medusa.jcu.edu.au/Dragonflies/openset/displaySpecies.php?spid=3668

Hagen, Hermann. "16. A. exsulans! Agrion exsulans Hagen!" Synopsis of the Neuroptera of North America. With a List of the South American Species: 82-83. Smithsonian Miscellaneous Collections, vol. IV, art. I. Translated from Latin to English by Philip Reese Uhler. Washington DC: Smithsonian Institution, July 1861.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/18918185
Available via HathiTrust @ https://hdl.handle.net/2027/aeu.ark:/13960/t32241f34?urlappend=%3Bseq=117

Paulson, Dennis. Dragonflies and Damselflies of the East. Princeton NJ: Princeton University Press, Princeton Field Guides, 2011.

"The 2012 USDA Plant Hardiness Zone Map." The National Gardening Association > Gardening Tools > Learning Library USDA Hardiness Zone > USDA Plant Hardiness Zone Map.
Available @ https://garden.org/nga/zipzone/2012/