Magicicadas mate and lay hundreds of their eggs on tree trunks during their several weeks' lifespan. They spend 13 or 17 years underground as juveniles, and after emerging, they mate in giant groups, luring each other with loud calls. Females mostly lay their eggs on concavities of tree trunks, and when they hatch, the young cicadas drop to the ground and instinctively burrow themselves underground for another 13 or 17 years as juveniles. Show more