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Dragonflies and Damselflies - Ancient Insects, Surviving in our Modern World
by John and Jane Balaban, North Branch Restoration Project
August 11, 2012
Dragonflies and Damselflies belong to the order Odonata ("toothed ones"), referring to their serrate mandibles. These are ancient insects with fossil records from 250 million years ago, when dinosaurs walked the earth. Odonata is a small order compared to other insect orders. There are around 5000 species of Odonata world-wide (beetles have 250,000; butterflies 125,000), with 430 species in North America.
John began his fascinating presentation by explaining the difference between dragonflies and damselflies. He showed photographs of the different species in their natural habitat and pointed out identifying characters such as size, body type, coloration, flight pattern, wing positions at rest, and mating rituals.
Widow Skimmer female, Libellula luctuosa
The order Odonata has two suborders. Dragonflies are in the suborder Anisoptera (unequal wings) which includes Darners, Clubtails, Emeralds and Skimmers. They hold their wings spread horizontally when they perch. The hind wings are broader than the forewings, thus are "unequal". They have large compound eyes and have excellent vision.
Some dragonflies can be as large as 3 to 3 3/4 inches long. Others are only 3/4 to 1 1/2 inches long. They are strong flyers, agile and able to fly long distances. They are carnivorous, preying on other insects (including other odonates!) caught in mid-flight. Their agility and excellent vision make them voracious hunters.
Damselflies are in the Zygoptera (twin wings) which includes Broad-winged Damsels, Spreadwings and Pond Damsels. Damselflies are smaller more delicate animals than dragonflies and generally hold their wings over back when they perch.
John explained that Dragonflies and Damselflies undergo three stages of development, from egg to larva to adult. They spend most of their lives underwater as larvae, living at the bottom of ponds or stream beds and undergoing 9-15 molts as they mature. The time to adult stage can vary from 3 months to 8 years, depending on the species. When the timing is right, the larva crawls out of the water onto a rock or twig, where it swallows air to increase its internal pressure, causing the exoskeleton to split and allow the fully formed adult to emerge and expand. The newly emerged animal is soft ("teneral") and vulnerable to predators. As soon as it can fly, it moves to a protected place where its body can harden. Early on, it has little of the color that will be a characteristic of the fully developed adult.
The adult stage is the shortest part of the life cycle, lasting a matter of months; the purpose now is to mate and reproduce. After mating has occurred, the female will deposit her fertilized eggs in water or nearby vegetation, beginning the next generation's cycle of life.
The Hines Emerald Dragonfly is the only federally endangered odonate. Because its existence is threatened, its habitat is being protected in the Lemont area as well as other locations where it is known to occur, such as Cedarburg Bog in Wisconsin. The Hines is dependent upon wetland habitats suited for egg laying and larval development. The adult requires natural plant communities near the breeding habitat; these communities include fen, marsh, and sedge meadows with bordering fringes of shrubs..
Following John and Jane's slide presentation, the group took a nature hike to the edge of the pond on the 1 Aloha Lane property in search of Odonates. It was a beautiful sunny afternoon and wildlife greeted us all around. There were ducks swimming on the pond, turtles sunning themselves on logs and a few bull frogs surfacing here and there with a splash. Dragonflies cruised back and forth over the pond. Jane demonstrated the proper way to hold the animals without harming them, affording the class a close look at some of these lovely creatures. The following species were seen at the pond: Pond Hawk, Blue Dasher, Widow Skimmer, Green Darner and Eastern Forktail. It was a wonderful and magical afternoon surrounded by the diversity and energy of nature.
The Pond Hawk Female, Erythemis simplicollis
Each of the 430 North American Dragonflies and Damselflies species are spectacular and unique. These fascinating creatures inspire us to want to know more about them. Scientists, experts and citizen enthusiasts have devoted their lives to searching for and learning about them over years and decades. As a result, volumes of information with descriptions and beautiful photographs are available as resources today. For more information, check out the links below.
Illinois Odonate Survey engages citizen scientists gathering information about our local odonate populations. Contact Gareth Blakely (email@example.com) for more information or visit the new website and FaceBook page. www.illinoisodes.org http://www.facebook.com/pages/Illinois-Odonate-Survey/199366633463614?ref=hl
The Field Museum has developed a number of RapidGuides to flora and fauna of our region: http://fm2.fieldmuseum.org/plantguides/rcg_intro.asp?zone=temperate Two of the guides listed there are for odonates: Common Dragonflies and Damselflies of the Chicago Region and Damselflies of Chicagoland. All the guides are downloadable at no charge.
Bugguide is an excellent online reference with many photographic images organized into an electronic field guide. The link to the Info page for Odonata has a long list of books and other references: http://bugguide.net/node/view/77 The Info pages for the suborders (click on Taxonomy to see the suborder links) have more specific information about characteristics and life history of the two.
ANISOPTERA - Dragonflies and ZYGOPTERA - Damselflies Species List
by Jane and John Balaban
Photos by Tom Lovestrand
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