The Periodical Cicada and it's wonderfully long life cycle

Last summer, I had the privilege of witnessing one of nature’s greatest spectacles; the emergence of a brood of periodic cicadas. However, this particular event was special, once in a lifetime even; a double brood event, meaning that two cicada broods emerge simultaneously. For this, I made a special expedition to the wilds of Springfield, Illinois due to the fact that it was an area where the two cicada broods overlap.(1) Today, let’s explore what makes these insects so fascinating.

The term “periodical cicada” can actually refer to one of several species of cicada in the genus Magicicada. All native to eastern North America, these insects are well known for their distinctive reproductive cycle. In the beginning, a cicada hatches from an egg typically laid on branches and twigs. Upon hatching, the young cicada will proceed to make their way underground, where they will stay and feed on tree sap for over a decade.(3) For the species M. tredecim, M. neotredecim, M. tredecassini, & M. tredecula, This represents a period of 13 years; they are beat in this regard by M. septendecim, M. Cassini, & M. septendecula, which spend a whopping 17 years underground.(2) After this extensive period of digging tunnels and feeding on plant roots, the cicada will then become a nymph, which sees them digging to the surface and shedding their exoskeletons to develop into their adult form. It is in this adult form that we hear the distinctive calls of the cicada, produced by the males for the purpose of attracting a mate. After mating, the cicadas die off, in which the life cycle starts anew.(3) It should be noted that all species of cicada follow a similar outline for their life cycles, albeit within different time frames.

The method by which these critters create their signature sound is also quite fascinating. Insects, and by extension cicadas, do not posses many of the organs that many vertebrates, such as ourselves, use to produce sound; these include organs such as lungs, tracheas, voice boxes, and tounges. Instead, cicadas have developed the ability to produce noise through a combination of two methods. The first of these methods is through rubbing it’s wings together in a fashion not too dissimilar to the way that crickets rub their legs together to produce their distinct nighttime call. The other method that cicadas use to produce their sound is through the use of an organ known as a tymbal. The tymbal is a series of ribs that cicadas flex to produce sound. To borrow an analogy from Kyle Scheiber, who wrote on behalf of the Peggy Notebaert Nature Museum of the Chicago Academy of the Sciences, “The action is like how a bendy straw makes sound: pulling and pushing the ribs of the bendy straw together makes a series of clicks. If you could push, pull, and twist a bendy straw hundreds of times a second the sound of the clicks would be so close together that you’d only hear a buzzing sound: this is how fast the cicada is able to vibrate its tymbal.”(6)

From the perspective of a large mammal such as ourselves, this may not necessarily seem like an exhilarating subject, the effects can be earthshaking when felt from the emergence of billions of insects, as is what happens with the periodical cicada. When walking through the forest, it felt as though I was immersed in an alien landscape. At all hours of the day, the normal quiet background soundscape of the woods was replaced by the constant droning of billions upon billions of inch long insects, trying to make the most of their short 4-6 weeks on the surface to continue the species. In the branches and stems of the understory the diligent naturalist can find the small exoskeletons left behind by the nymphs when growing into adults, a physical echo of their subterranean life. Even the soil is changed, with any exposed patches becoming a trypophobic mosaic of holes left from the emerging cicadas.

While this special double emergence of overlapping periodical cicada brood was rare, specifically only happening once every 221 years, researchers have studied both it and past periodical cicada events and have found that these small creatures can have significant impacts on the ecosystems they call home. One paper that has been crafted from this research is “Activity responses of a mammal community to a 17-year cicada emergence event” by Alex S Proudman, Landon Jones, Morgan O Watkins, & Elizabeth Flaherty. Published in the Journal of Mammalogy, the researchers used trail cameras and audio recording devices to monitor various mammal species in Northwest Indiana. They found that raccoons significantly changed their behavior in response to the cicadas, indicating that they may have fed extensively on periodic cicadas, while white-tailed deer had a significant decrease in activity, likely due to the noise of the cicadas.(5) Another study conducted to research the effects of periodic cicada is “Influences of a periodical cicada emergence on eastern phoebe reproduction and behavior” by Allison M Klement. In this study, it was found that Sayornis phoebe, or the Eastern phoebe, more rapidly laid second egg clutches, had bigger second clutches, and overall had a more productive breeding season during a periodical cicada event in 2004 as compared to a more typical year in 2005.(4)
Experiencing this once in a lifetime event was one of the best experiences of my life. While much has, rightfully, been made about seeing the great migrations of the Serengeti or the migrations of the titanic baleen whales, the periodical cicada reminds us that the wonder of nature can also be found in the small creatures and places that are often overlooked. It’s a reminder to always be on the lookout for the treasures of the natural world because you never how it’s small things will surprise you in a big way.

Citations & Farther Reading
1.Borenstein, S. (2024, June 14). Illinois is hit with Cicada Chaos. this is what it’s like to see, hear and feel billions of bugs. AP News. https://apnews.com/article/cicada-invasion-buzz-alien-illinois-bugs-ab82f46e224ea56a44302a3b569e8074

2.Cooley, J. (2017, February 17). Species. Periodical Cicada Information Pages. https://cicadas.uconn.edu/species/
3.Jesse. (2024, May 29). The 3 stages of the cicada life cycle. Wildlife Informer. https://wildlifeinformer.com/cicada-life-cycle/
4.Klement, A. M. (n.d.). Influences of a periodical cicada emergence on eastern Phoebe reproduction and behavior. Purdue e-Pubs. https://docs.lib.purdue.edu/dissertations/AAI1490670/
5.Proudman, A. S., Jones, L. R., Watkins, M. O., & Flaherty, E. A. (2024). Activity responses of a mammal community to a 17-year cicada emergence event. Journal of Mammalogy, 105(5), 1190–1199. https://doi.org/10.1093/jmammal/gyae062
6.Schiber, K. (2017, August 25). How do cicadas make sound?. Nature Museum. https://naturemuseum.org/cas/blog/how-do-cicadas-make-sound