Late July is usually when I start to notice the beautiful golden-hued Wandering Gliders showing up around town. I’ve seen a few around the ponds lately, and spent some time stalking one near the footbridge earlier today. It would follow a predictable path up and down the paved bike path, dropping lower and lower each time. Every time it dropped to about ankle height I thought it would land, but then it would see something and zip off in another direction up to 15 feet above the ground. After a while I gave up, but then when I reached the southern-most pond I found another one. This one landed right in front of me!
Wandering Gliders are called “gliders” for a reason – they spend most of their time in flight. First described by Johan Christian Fabricius in 1798, the Wandering Glider (also called the Globe Skimmer) is thought to be the most widespread dragonfly species in the world, found in good numbers on every continent, except Antarctica, and even at sea! Wandering Gliders are migratory, and one individual can fly about 7,000 – 8,000 km. A study published in 2016 showed that there is very little genetic difference between gliders caught in different parts of the world, suggesting that this species forms one large, interbreeding global population rather than several distinct, discrete populations which do not interact.
The Wandering Glider is part of a group known as the “rainpool gliders”. They need fresh water to breed, such as ponds and temporary pools, which is what they are searching for on these long journeys – they follow shifting weather and rainfall patterns so that they are able to reproduce year-round. This strategy differs from most members of the skimmer family, which emerge as adults in May or June and reproduce until the adult population dies out two or three months later. For example, the study noted that once the dry season begins in India, individuals migrate to Africa just as the rainy seasons is starting there.
Although the Wandering Glider is one of the larger members of the skimmer family, at about 2 inches it is still a tiny insect with wings smaller than that of the Monarch butterfly, whose famous 4,000 km winter journey is much better known and understood. This made me wonder where the two individuals I saw came from, and whether they planned to stay and breed at the ponds for the rest of their adult lives, or if they were just stopping by on their way to somewhere else.
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