Pretty … and pretty deadly! Although elegant in flight, and when perched, the beauty of their coloration is undeniable, the Common Green Darner is also an efficient and effective air-borne predator, which accounts for this species being one of the most prolific, abundant, and far spread of all dragonflies throughout North America.
All dragonfly species originated as part of a more ancient order called Odonate (translated as toothed ones), alongside damselflies. Two branches emerged from this original order: Anisoptera (dragonflies) and Zygoptera (damselflies). Both are plentiful within the Cataraqui Region and on first blush can be confused for one another.
In almost every dragonfly species, including the Common Green Darner, its eyes are quite close together in the middle of its head. For damselflies, the eyes are more widely separated. Another significant difference is that when at rest or perched, dragonflies’ wings are in a horizontal position, while damselflies fold them over onto their backs.
While both species are quite agile and effective fliers (due to each wing moving independently), dragonflies seem to have more strength while in the air, and are able to sustain their path more directly, even in a breeze. Damselflies are described as relatively “weak and fluttery” in flight.
According to the Nature Conservancy of Canada, the Green Darner earned its unique moniker for its resemblance to a darning needle thanks to its long, slender abdomen. It’s also remarkable for its vibrant colouring.
“The Green Darner has a yellowish-green face, large dark eyes and a dark spot on the top of its head. Males have a dark green thorax and light-blue abdomen, while females and immature dragonflies have a paler green, reddish and brown abdomen. A dark line runs down the upper side of the abdomen in both sexes.”
For almost all Odonates, including dragonflies, like the Green Darner, eyesight is their most noteworthy trait, contributing to their elusiveness as prey and also their documented 98 per cent success rate in capturing the prey they have set their nearly 360-degree vision upon. Those prey generally include other flying insects such as flies, moths, butterflies, mayflies, mosquitoes, their distant cousin damselflies and even small fish/tadpoles who get too close to the water’s surface.
The spread of this species is impressive, as it inhabits almost all of the continental United States, southern Canada and parts of northern Mexico.
One of the most fascinating features of the Green Darner is its lengthy annual migration which takes millions of them down to Central America. They have also been observed in Hawaii, the Caribbean, China and the far east of Russia.
A first generation of Darner emerges from its larval state in February and March in the southern U.S., Mexico and the Caribbean. These travel north to New England, the upper U.S. Midwest and southern parts of Canada. Upon arrival they lay eggs … and die.
When the second generation emerges, many will overwinter as nymphs, but most will mature and head back south again from late July to early October (which is when we in the Cataraqui Region see them most prominently). The southern-heading Green Darners return to where the first generation came from, laying their eggs before expiring. This third generation stays put, mating and laying the eggs that emerge in January/February to start the cycle all over again.
An article in the Smithsonian Magazine from 2019 talked about the importance of studying these migratory habits and how they’re being impacted by the effects of human-made climate change.
“With climate change we could see dragonflies migrating north earlier and staying later in the fall, which could alter their entire biology and life history,” the article said, adding that this phenomena could also apply to other migratory insects such as butterflies.
Have you seen Common Green Darners flitting about your home or out on a walk through one of our conservation areas? If so, take a photo and tag us in it. We will share it on our social media channels.
- Sources: Smithsonian Magazine, Wikipedia, University of Minnesota Department of Entomology, Nature Conservancy Canada, Kingston Field Naturalists, Trail and Landscape Magazine (Ottawa).