Monday, June 15, 2015

Plathemis lydia: Chalky Blue White of Male Common Whitetail Dragonfly


Summary: Plathemis lydia is a New World dragonfly native to Canada, the U.S., and Mexico. The males display startling coloring, with chalky blue-white abdomen.


female Common Whitetail, Town of Skaneateles, Onondaga County, upstate New York: R. A. Nonenmacher, CC BY SA 3.0, via Wikimedia Commons

Plathemis lydia is a New World dragonfly native to North America from southern Canada southward across the United States and into Mexico.
In Canada, Plathemis lydia enjoys a coast-to-coast range across southern Canada’s ten provinces.
In the United States, Plathemis lydia claims homelands throughout the continental, or Lower 48, United States.
Plathemis lydia, which has a scientific synonym of Libellula lydia, is known commonly in English as Common Whitetail.
Common Whitetail dragonflies favor the moist environment of slow-moving or standing water bodies, such as creeks, lakes, marshes, ponds, and streams. They accept other still water ecosystems such as ditches and wetland meadows.
As members of the world’s largest dragonfly family, the skimmers or perchers (Libellulidae), Common Whitetail dragonflies hover over water and perch in nearby, open habitats. Their favorite ground sites are on logs and rocks, as well as at muddy locales. Branches are favored for aboveground sites.

Robber fly (Trioria interrupta) preys upon hapless Common Whitetail (Plathemis lydia): Thomas Shahan, CC BY 2.0, via Wikimedia Commons

Membership in the carnivorous order of insects, the Odonata (Ancient Greek: οδόντoς, odontos, “tooth”) signals the diet of Common Whitetails as insectivores (Latin: insectum, “animal with divided or notched body” + vorare, “devour, swallow”).
As adults, Common Whitetails adeptly tackle their prey, such flying insects as gnats and mosquitoes, in mid-air offensives.
The threat of predation is not restricted to Common Whitetail young'uns, known as naiads or nymphs. Young'uns are favored by birds, fish and frogs, as well as by aquatic insects, including other dragonflies.
A particularly fearsome predator of adult Common Whitetails is the robber fly (Trioria interrupta). The aggressive insectivore specializes in fatal and swift aerial ambushes.
Through their differing appearances and sizes, smaller females and larger males exhibit sexual dimorphism (Ancient Greek: δίς, dís, “twice” + μορφή, morphḗ, “form, shape” + -ισμός, -ismós, suffix forming abstract nouns).
The short, stout abdomen in males presents a chalky blue-white coloring.
In females, brown predominates across the short, stout abdomen. Creamy white diagonal spots create a sawtooth pattern along the side.
Immature males resemble females in abdominal coloring and pattern.
Wing patterns distinguish females and males.
Males have two sets of brown-black bands on each translucent-tipped wing. A swath of white triangulates beneath the smaller, inner bands on either side of the abdomen.
Immature males resemble adult males in their wing pattern.
Females have three sets of dark bands on each wing. All wingtips are darkened with the third band.

On a walk this year (2015) on Sunday, June 14, along a nature trail about 4 miles (6.4 kilometers) south of my home, I was gently buzzed by a male Common Whitetail as he flew from a muddy patch in the gravel parking lot to his perch in a stand of deciduous trees generously lining the trail’s stream.
The chalky blue whiteness of his abdomen was startlingly unusual and set off his dark-banded, translucent wings with aesthetic perfection.

male Common Whitetail: Bruce Marlin, CC BY SA 2.5, 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:
Robber fly (Trioria interrupta) preys upon hapless Common Whitetail (Plathemis lydia): Thomas Shahan, CC BY 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Robber_Fly_(Triorla_interrupta)_with_Dragonfly_(Plathemis_lydia).jpg
female Common Whitetail, Town of Skaneateles, Onondaga County, upstate New York: R. A. Nonenmacher, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Dragonfly_ran-579_Whitetail_f.jpg
honoring both parents, with wing pattern like papa's and abdominal pattern like mama's ~ immature male Common Whitetail, Québec, eastern Canada: Alexandre Dion, CC BY 2.5, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:CommonWhitetail_juvenile_male.jpg
male Common Whitetail: Bruce Marlin, CC BY SA 2.5, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Common_whitetail.jpg

For further information:
“Common whitetail (Plathemis lydia).” Arkive > Species > Invertebrates – terrestrial and freshwater. Last updated 8/13/2014.
Available @ http://www.arkive.org/common-whitetail/plathemis-lydia/
“Common Whitetail Skimmer – (Libellula lydia).” InsectIdentification.org > Dragonflies & Damselflies.
Available @ http://www.insectidentification.org/insect-description.asp?identification=Common-Whitetail-Skimmer
“Plathemis lydia – Common Whitetail.” BugGuide > Guide > Arthropods (Arthropoda) > Hexapods (Hexapoda) > Insects (Insecta) > Dragonflies and Damselflies (Odonata) > Dragonflies (Anisoptera) > Skimmers (Libellulidae) > Whitetails (Plathemis).
Available @ http://bugguide.net/node/view/603
Van Dokkum, Pieter. Dragonflies: Magnificent Creatures of Water, Air, and Land. New Haven CT and London UK: Yale University Press, 2015.



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