Bzzzz…. Who’s That?

By Lizbeth He

Since 2021, an all too familiar sound has been missing from the normal summertime ambiance: the inescapable buzzing of cicadas. These insects are relatively large and can range anywhere from 1 to 2 inches long. They have sturdy bodies, protruding eyes, membranous wings, and needle-like mouthparts. The loud buzzing sound they produce stems from the adult males attempting to attract potential female mates. The pitch, tone, frequency, and volume of the buzzing is all unique to the different cicada species (Dunham). Another key feature of cicadas is that they shed their exoskeletons. Because their exoskeleton is very hard and restricting, cicadas need to go through the process of ecdysis, also called molting, to shed and continue growing (Miller). This accounts for another noteworthy characteristic of cicadas that many often find repulsive.

However, it is not every year that all cicada species emerge. Around the world, there are more than 3,400 species of cicada. Only nine of these species periodically emerge, and among those, seven species reside in North America. Cicadas from these seven broods emerge from the ground either every 13 or 17 years to mate and lay eggs. These staggering cycles is also why cicadas have not appeared since 2021. Generally, about three to four weeks after they emerge, the cicadas will die after reproducing. The new generation of insects then returns underground until the cycle repeats (Bartels). There, they feed on xylem, or plant juices, from the roots of different trees and shrubs (Dunham). Their habits of emerging and returning underground is something unique to these broods of cicadas. 

Evidently, the chances of these staggering emergence cycles lining up is very low. That is why 2024 is a special year, as the 13-year Great Southern Brood (Brood XIX) and the 17-year Northern Illinois Brood (Brood XIII) will co-emerge in a so-called ‘double brood.’ Although a 13-year and 17-year brood generally appear at the same time every 5-6 years, this time the two broods are also adjacent to each other. This adds to their rarity as adjacent broods typically only emerge together every 25 years. Consequently, this is the first time since 1998 that adjacent 13-year and 17-year broods have emerged in the same year. Furthermore, any two specific broods with different life cycles only co-emerge every 221 years. For these two specific broods (XIX and XIII), the last time that they co-emerged was in 1803 (“The 2024 Periodical Cicada Emergence”). 2024 is a very special year for these periodical cicadas.

So, while spending time outdoors this summer, although the cicadas and their buzzing may seem like double the headache, remember that this is a rare and significant occurrence. After all, the next time these two specific breeds will co-emerge again is in 2245, more than two centuries from now.

Works Cited

"The 2024 Periodical Cicada Emergence." University of Conneticut, 16 Feb. 2017, cicadas.uconn.edu/.

Bartels, Meghan. "A ‘Double Brood’ of Periodical Cicadas Will Emerge in 2024." Scientific American, 11 Mar. 2024, www.scientificamerican.com/article/a-double-brood-of-periodical-cicadas-will-emerge-in-2024/.

"Broods." University of Conneticut, 27 Feb. 2017, cicadas.uconn.edu/broods/.

Dunham, Will. "When and where double brood of cicadas will emerge - and what to expect." Reuters.com, 13 Mar. 2024, www.reuters.com/world/us/when-double-brood-cicadas-will-come-out-what-expect-2024-02-19/.

"General Periodical Cicada Information." University of Connecticut, 16 Feb. 2017, cicadas.uconn.edu/general_information/.

Miller, Korin. "Why Do Cicadas Molt? Experts Say You’ll See Gross Skins Everywhere This Summer." Yahoo Sports, 19 May 2021, sports.yahoo.com/why-cicadas-molt-experts-ll-151800121.html?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8&guce_referrer_sig=AQAAABZBK5vyat-XJhVSh9Zszb0b9kcCj7YexNDRxnwG2VXnaLvf4r8FrgyHIXBee6E23wWS0dR_9B8BQxYZZYCbor4oMMVcBkHpKFrVeAL8FUJ0DaJAO-DgLOc6JK41pgsBgmmucMZSBXeeAAv7b0yZAuoUmqWvl2ovaMQYzzzWF9HO#:~:text=%E2%80%9CBecause%20the%20exoskeleton%20is%20hard,and%20shed%20their%20nymph%20skin.