Cicadas leave their old skin behind

Can a creature spend seventeen years in total darkness only to die five weeks after seeing the sun? Periodical cicadas live most of their lives as pale, wingless nymphs, tunneling through the soil and sucking fluid from tree roots in a decade-long subterranean trance.

They aren't hibernating. They are counting the years by tracking the ebb and flow of fluid inside the roots they feed on, waiting for a thermal signal from the soil above. When the ground temperature at a depth of 8 inches reaches approximately 64 degrees Fahrenheit (18 degrees Celsius), billions of them crawl out in a synchronized emergence that overwhelms every predator in the forest.

Their transformation is a violent structural renovation. Once they claw their way onto a tree trunk, their golden-brown exoskeleton splits down the middle. A soft, white adult pushes itself out of its own back, unfurling wings that look like stained glass. Within hours, their new skin hardens into a black armor, and their eyes turn a vivid, blood-red.

The noise that follows is louder than a lawnmower. Male cicadas possess specialized organs called tymbals-ribbed membranes on their abdomens that they buckle and snap back like the lid of a tin can. They do this hundreds of times per second, turning their hollow bellies into resonance chambers to create a mechanical scream designed to attract a mate.

This frantic, deafening party is their final act. After nearly two decades of patient waiting, the adults spend their final weeks feeding on plant fluids and focusing purely on reproduction. Once the eggs are laid in the slits of tree branches, the adults drop to the forest floor and rot, their bodies providing a massive, sudden injection of nitrogen into the soil.

The tiny hatchlings that emerge from those branches don't fly; they simply let go, falling like dust to the ground and digging immediately into the dirt to begin a silence that will last until the year 2041.