In a fascinating natural event not witnessed since 1803, billions, if not trillions, of cicadas are expected to emerge from the underground in 17 U.S. states come April. These noisy flying insects, known for their distinctive appearance and behavior, will engage in a frenzied mating ritual that will last for several weeks before they eventually perish near trees. However, before their demise, they will lay eggs on forest floors, thus initiating a new cycle of life.
This upcoming emergence is particularly unique as it marks the first time in 221 years that two different types of cicadas, namely brood XIX and XIII, will rise from the ground simultaneously. This rare occurrence, last observed during Thomas Jefferson's presidency, is not anticipated to happen again until 2244.
Cicadas, measuring between one to two inches in length, boast sturdy bodies, bulging red compound eyes, and membranous wings with a wingspan of up to three inches. Despite their intimidating appearance, these insects pose no threat to humans, pets, gardens, or crops, as confirmed by the Environmental Protection Agency. In fact, they serve as a valuable food source for various bird and mammal species.
Furthermore, cicadas play a crucial role in ecosystem health. They help aerate lawns, enhance water filtration, and contribute nutrients to the soil through decomposition. While most cicada species emerge annually, the United States is home to two periodical broods that remain underground for either 13 or 17 years.
The simultaneous emergence of broods with different cycles is a rare occurrence due to the unique prime number intervals of 13 and 17 years. This convergence only happens once every 221 years, as explained by cicada experts.
Brood XIII cicadas follow a 17-year cycle and are primarily found in northern Illinois, eastern Iowa, southern Wisconsin, and select counties in extreme northwestern Indiana. On the other hand, Brood XIX emerges on a slightly shorter 13-year cycle and is distributed across 15 states, including Alabama, Arkansas, Georgia, and others.
These two broods overlap in central Illinois and occasionally in Indiana, potentially leading to interbreeding between the groups. Female cicadas lay eggs in tree branches, with each slit typically containing 20 to 30 eggs. A single female can lay between 400 to 600 eggs in her lifetime, with the eggs hatching in late July to early August.
While the cicadas' presence may be overwhelming due to their sheer numbers and loud calls, they do not pose a threat to humans. However, young trees may be at risk as the insects lay their eggs in small branches, potentially harming the tree. The EPA recommends protecting young trees by covering them with mesh or netting to prevent cicada damage.
