Sounds of Summer: Brood X

By Bre Myers

“I feel like I have cicadas in my head” is a regional description of tinnitus I have heard more than a few times in my career. Now, with the emergence of Brood X in the Northeast/Mid-Atlantic section of the United States, that drone is stimulating most everyone’s auditory cortex. Once quiet walks in the woods are exchanged for a cacophony of millions of simultaneous and overlapping clicks from male cicadas looking for mates.

The buzzing sound emanates from a drum-like structure on the abdomen called the tymbal structure. According to the National Institute on Deafness and other Communication Disorders (NIDCD, 2021) at the National Institutes of Health (NIH), the intensity of the rapidly moving tymbal can reach up to 90 dBA, making the cicadas one of the loudest insects on the planet. My own recording peaked at about 72 dBA, which is roughly equivalent to busy traffic.

The cicadas also have an acoustic reflex response of sorts. A tiny tendon contracts to stiffen their tympana, so that their hearing ability isn’t harmed during their buzzing. It may seem counterproductive for millions of cicadas to congregate in the same area to find a mate; talk about a cocktail party effect! However, there is strength in numbers, as the joint buzzing sounds are a turnoff to predators, like birds.

While my normal respite of quiet solitude while hiking has been hijacked by these creatures, the audiologist in me marvels at the communication strategies of these insects. In past years, cicada sounds could be heard in waves of varying intensities beginning midday and continuing through dusk. You may notice it at first but can soon habituate to it.

The current levels are much harder to ignore, and while there is some undulation in the signal, it is constant morning to dusk in my corner of southeastern Pennsylvania. The optimist in me hopes that the sound offers some natural masking to those with tinnitus. The pessimist in me complains that they must be violating noise ordinances!

Regardless of which mood I am in, it is a wonder to witness the phenomenon and have a clearer understanding of how their distinct mating call permeates the soundscape. Unlike tinnitus, this sound will only be with us for a few weeks, so perhaps try to enjoy it while you can?

Watch a video of cicadas.

Bre Myers, AuD, PhD, is an associate editor for www.audiology.org and Audiology Today magazine.

References

How Stuff Works. (2020) How cicadas work. (accessed on June 7, 2021).

National Institute on Deafness and other Communication Disorders. (2021) Cicadas can make as much noise as a motorcycle. (accessed June 7, 2021).