In a curious phenomenon that occurs every 13 years, Middle Tennessee is bracing itself for an invasion of millions of cicadas. Reports indicate that a few of these noisy insects have already been spotted emerging from the ground in Murfreesboro, with more expected to follow suit in the coming weeks.

The cicadas, known for their distinct buzzing sound, go through a lifecycle that involves an underground phase, followed by an adult emergence stage. Jason Oliver, a Research Professor of Entomology at TSU, explains that the cicadas will crawl out of the ground, find a secure place to shed their nymphal exoskeleton, and then begin the process of hardening their wings. Once their wings are fully developed, they take flight and head towards the tree canopies.

It is during this stage that the male cicadas congregate in the tree canopies and produce their characteristic loud noises to attract the females. Interestingly, there are two different broods emerging this year - the 13-year and the 17-year broods. Middle Tennessee will primarily experience the millions from the 13-year brood, while Central Illinois will be exposed to an overlapping species.

Female cicadas lay their eggs by cutting slits in tree branches, depositing up to 60 eggs per notch. The eggs will hatch within 15 days to a month, and the tiny nymphs will resemble ants. These nymphs will then make their way back into the ground, searching for a tree root to attach themselves to and begin their own cycle of development.

Dr. Oliver notes that the loudness of the cicadas will be most intense when the majority of them have reached the adult stage. This stage typically lasts around six weeks, extending into June and potentially declining by mid-July. However, just as these cicadas make their exit, another species known as the Annular Dog Day cicadas will make their appearance in July and August. These cicadas have a shorter lifecycle and are relatively quieter due to their smaller numbers.

What fascinates scientists is how cicadas are able to emerge precisely after 13 or 17 years. Dr. Oliver suggests that the sap flow cycles within trees play a significant role in signaling the passage of time to the cicadas. Additionally, the 17-year brood has a unique ability to delay its development during the second nymphal stage, effectively adding an extra four years to their life cycle.

As Middle Tennessee prepares for this extraordinary event, it is important to remember that the cicadas will not only provide a noisy month for residents but also serve as a vital food source for birds, contributing to the ecosystem's natural balance.

The emergence of millions of cicadas is a remarkable phenomenon that reminds us of the wonders of nature and the diverse cycles that play out beneath our feet.