Dragonflies abound! Dashers, darners, skimmers and gliders, to name just a few, have been darting around the island all summer. But it is the preponderance of wandering gliders that has captured the wonderings of many of us, since the blurry eye of Tropical Storm Henri passed over us this past Sunday afternoon.
Wandering gliders are the world’s most wide-spread species. They are found on every continent except Antarctica (and alas, the way things are going, they may be there before long). More locally, they are found throughout the U.S. and as far north as Newfoundland. Wandering gliders are a migratory species and are known for their long-duration migrations, over both land and ocean. You may have noticed: they are fast and zippy and rarely stop moving. When they do rest, you will find them low to the ground hanging vertically. Their flight pattern is marked by long periods of gliding, alternating with several fast wing beats, thus the glider part of their name.
Wandering gliders are in the genus Pantala – rainpool gliders. Their numbers increase when there is a wet summer with more rain, and more temporary pools of rainwater. Sound familiar?
Dragonflies in general, lay eggs in water; the eggs pupate into a larvae known as nymphs, which also live in water; and, when the time comes the larvae crawl out of the water and emerge as dragonflies. This description is simplified of course, there is a lot of amazing biology involved, and... perhaps a little magic. The key point is that when the conditions are right, large numbers of eggs are laid at the same time, which, when conditions are right, results in large numbers of that species also emerging in large hatch numbers.
Dragonflies (and their near relatives the damselflies) abound on Block Island throughout the extended summer. Each species reproduces on its own specialized schedule. But mid-August through early October is the time to see and observe regular periods of hatching, swarming dragonflies. They are beautiful, fascinating and carnivorous! Among other things, they eat millions of mosquitos, gnats and no-see-ums.
Exactly why so many are here on Block Island now is likely a combination of factors; including a hearty breeding year and the weather pattern of Henri pushing the little sprites around. Does it really matter why here, why now? Enjoy the moment, they are amazing.
Extra note: other dragonflies also seen this week included common green darners, 12-spotted skimmers, and blue dashers. Keep your eyes open, you never know what you’ll see. And, if you are so inclined, check out one of the many community science sites to learn more and report your sightings. The world needs all the amateur naturalists that it can get.
www.fs.usda.gov/working-with-us/citizen-science/pond-watch-migratory-dra... and, The Dragonfly Swarm Project at www.thedragonflywoman.com/dsp/.
Many thanks to those who contributed bits and pieces to this article: David Gregg, Nigel Grindley, Ginger Brown, Austin Morin and “Dragonflies through Binoculars” by Sidney Dunkle.