Dragonflies are seriously cool - a flashback to prehistoric times, they zoom and hover, swerve and dart. They also live the first part of their lives underwater, in lakes, ponds, and rivers. The larvae are alien-looking predators, with a lower lip structure that flashed out in a nano-second to snatch unsuspecting prey back into the waiting jaws. When they are ready to molt into the winged adults that most people are familiar with, the larvae, their skins stuffed-to-bustin' with wings and other paraphernalia of their future selves, make their way to the water's surface to transition into a terrestrial (and aerial!) iteration. Anchoring to shoreline vegetation, soil, even bridge abutments, these awkward little larvae cling and begin to dry their outer skins.
As the skin hardens, and as the new body inside swells, the outer "husk" begins to split, allowing the adult dragonfly to begin to emerge. Even the insect's respiration system is completely transformed from breathing oxygen dissolved in the water to breathing air from the bright new airy world around them.
They fill their wings with a kind of blood, unfurling their long, new bodies as their wings harden. Then they fly off, leaving behind their old skins, intricate and empty shells of their former selves.
I spent Sunday morning with our 2 kids and our 2 dogs, kayaking up to the Paddock Road bridge, which spans the Black River about a quarter-mile above our house. I had the wonderful fortune to discover 15 empty skins ("exuviae") left behind from what turns out to be Fawn Darner (Boyera vinosa) dragonflies! They were all carefully hooked to the smooth concrete of the right bridge abutment. Interestingly, there were none on the left abutment. A little research turns up that most dragonflies emerge during the night to take advantage of the lack of bird predation - the right abutment faces the rising sun, so it likely affords the little larvae some extra drying time before take-off!