The 17 year Cicada Miracle

adult 17 year cicada

The visit with our daughter, Alli, who lives in North Carolina, coincided with the emergence of the 17 year cicadas. It was magical experiencing a small part of a cicada’s life. 17 year cicadas have the longest known insect life cycle.

Amazingly, after 17 years the entire population (up to 1.5 million/acre) emerges all at once.

Holes where cicada’s emerged

The nymphs hatch from eggs in the trees after six weeks. The young crawl to the ground and dig up to 2 feet below the surface. During the 17 years, the nymphs molt five times and sustain themselves by feeding on the roots of trees.

When the nymphs emerge from the ground, they molt for the last time, and wait up to six days for their wings to harden.

The nymph emerges from the ground. Photo by Alli Platter.

The adult emerging from its nymph stage.
Photo by Alli Platter

Adult cicadas live only four to six more weeks—just long enough to mate, and lay eggs. One female will lay as many as 600 eggs dispersed in clutches of 20 throughout the forest.

Mating Cicadas

Why do Cicadas remain underground 17 years?

One theory is, they can protect their population by emerging in large numbers. Predators, like birds and raccoons will be able to stuff themselves, but there will still be a large number of cicadas that survive. Also, the 17 year cicadas appear so infrequently, that there aren’t any predators that can specialize on eating them.

Exoskeletons in the trees photo by Alli Platter

The males cluster in ‘chorus centers’ and call to attract females. Within six weeks of emerging from the ground the life cycle is complete and the adults die.