The cicadas are coming! The 2024 double emergence of Brood XII and XIX will bring billions of cicadas to northern Illinois. According to the Field Museum, the emergence of the Great Southern brood and the Northern brood simultaneously only happens every 221 years.  The periodical cicadas emerging this year are among the longest lived insects on the planet. Their life cycle spans 17 years, with 99% of that life spent underground.    When they emerge as adults, both females and males only live about a month above ground before dying.  Cicadas are notoriously loud insects. The buzzing song they make can reach up to 90 decibels, about the sound of a loud lawn mower or a motorcycle.    That may not sound too bad, but, here in northern Illinois, when broods emerge they can pack anywhere from 100,000 to 1 million insects into a single acre, depending on tree and soil coverage. A million cicadas buzzing away at 90 decibels is enough to give anyone a headache. But not all cicadas sing a song; only the males buzz away. They do so to attract female cicadas and find a mate. And each species of cicada has a unique song.

Female cicadas lay their eggs in tree branches that are usually 1 inch in diameter or less. They use their egg-laying organ to cut the branch and then lay their eggs in the cut. They typically lay 10 to 20 eggs per cut, and in total lay up to 600 eggs each in their reproduction cycle.   While this reproductive cycle won’t damage mature trees, new trees can be damaged by the females’ cuts and egg-laying process.   The eggs then stay in the trees for six to 10 weeks before cicada nymphs emerge. These nymphs then drop from their branches and start burrowing into the ground. They dig 8 to 12 inches into the ground and then feed on the tree roots for the next 17 years, growing and maturing, waiting their turn to emerge as adults and start the life cycle over again.