Cicada DNA Helps Explain Strange Breeding Cycle
As cicadas prepare to re-emerge, researchers study the insect's curious DNA.
Periodical cicadas spend most of their lives underground while surviving on bacteria and tree roots. When the ground thaws to 65°F (18°C) in the 13th or 17th year (depending on their species), they leave their homes to search for a mate.
Different broods of cicadas have different population sizes and different breeding schedules, but Brood 2, the population that will appear this month, is expected to fill the skies with millions of cicadas.
Some researchers think that cicadas developed their cycles through millennia of evolution. The ones that emerged on regular one- or two-year timelines were killed by waiting predators. The 13- and 17-year life cycles make it hard for predators to predict their emergence from underground nests.