A few days ago a friend invited me to join him on a dragonfly odyssey high on a ridge in a canyon east of Smithfield, Utah. What we observed can only be described as a natural phenomenon.
At 6 am, the sun was just cresting the Bear River Range as we arrived at our destination. We dropped off the ridge to search small cliff bands of Lake Bonneville conglomerate for our quarry. We were not disappointed.
Hundreds of dragonflies were just beginning to launch from the cliff bands to being their daily hunt. As many were still plastered to the rock face awaiting the critical temperature to activate. I was mesmerized while sun-lit wings glowed gold and silver. Questions filled my head. Why so concentrated far above the canyon bottom in this strange rock? At what temperatures are they active? How many species occupy this small space? How can there be enough prey to support this high population? How far do they range from this rest in their daily forays? A good research thesis for a USU grad student!
An updated Utah faunal list contains 94 species dragonflies and damselflies, or Odonate, with 5000 recorded world wide.
Odonates are aquatic or semi-aquatic as juveniles existing up to 6 years in their aquatic state. Thus, adults are most often seen near bodies of water and are frequently described as aquatic insects. However, many species range far from water. They are carnivorous throughout their life, mostly feeding on smaller insects.
Odonates can act as bioindicators of water quality because they rely on high quality water for proper development in early life. Since their diet consists entirely of insects, odonate density is directly proportional to the population of prey, and their abundance indicates the abundance of prey in the ecosystem. Species richness of vascular plants has also been positively correlated with the species richness of dragonflies in a given habitat. If one finds a wide variety of odonates, then a similarly wide variety of plants should also be present.
In addition, odonates are very sensitive to changes to average temperature. Many species have moved to higher elevations and latitudes as global temperature rises and habitats dry out. Changes to the life cycle have been recorded with increased development of the instar stages and smaller adult body size as the average temperature increases. As the territory of many species starts to overlap, the rate hybridization of species that normally do not come in contact is increasing. If global climate change continues many members of Odonata will start to disappear. They are one of the first insects to develop
Trivia: With 300 M years of flight evolution, dragonflies are supreme – longest nonstop distance (11,000 miles across oceans), helicopter maneuvers, eat and have sex on the wing, and near 40 mph top speed. They are amazingly efficient hunters with 95% success. And sight- 30,000 lenses allow 360 degree range and can see in ultraviolet light.
There wingspan can range from less than an inch to 6 inches and lifespan from a few weeks to a year. In Indonesia they are eaten as delicious snacks and considered good luck if one lands on your head.
This is Jack Greene for BAS- and boy am I wild about Utah!!
Images: Courtesy Pixabay, Guenther Lig, Photographer, https://pixabay.com/photos/dragonfly-wings-insect-nature-3456317/
Text: Jack Greene, USU Sustainability Program Volunteer, Bridgerland Audubon Society
Strand, Holly, Dragonflies, Wild About Utah, July 21, 2011, https://wildaboututah.org/dragonflies/
Morse, Susan, Dragonfly Spotting on Wildlife Refuges, Nov 14, 2019, https://www.fws.gov/refuges/features/dragonfly-spotting-on-wildlife-refuges.html
Wild Utah, Dragonflies and Damselflies, https://www.wildutah.us/index_dragon.html
Eight-spotted Dragonflies, Wild Utah, https://www.wildutah.us/html/insects_other/h_d_skimmer_8_spotted.html
Dragonflies, Lee Metcalf National Wildlife Refuge, US Fish & Wildlife Service, https://www.fws.gov/refuge/lee_metcalf/wildlife_and_habitat/dragonflies.html
Order Odanate, Dragonflies and Damselflies, Bugguide.net, Department of Entomology, Iowa State University, https://bugguide.net/node/view/77
Report Dragonfly and Damselfly sightings, much like eBird to:
Odonata Central, https://www.odonatacentral.org/#/
Paulsen, Dragonflies and Damselflies of the West, Princeton Field Guides, Princeton University Press, https://www.amazon.com/Dragonflies-Damselflies-Princeton-Field-Guides/dp/0691122814/
Kavanagh, James (Author), Leung, Raymond (Illustrator), Dragonflies & Damselflies: A Folding Pocket Guide to Familiar, Widespread North American Species, Wildlife and Nature Identification Pamphlet, Waterford Press, April 9, 2018 https://www.amazon.com/Dragonflies-Damselflies-Familiar-Widespread-Naturalist/dp/1583554750