Cicadas are insects known for their distinctive, loud sounds they produce during periodic emergence. They spend most of their lives underground as nymphs, sometimes for many years, before emerging as adults to fill the summer air with their songs. Their seasonal presence prompts curiosity about their sound’s nature and volume.
Measuring the Cicada’s Volume
Cicada sounds vary in decibel levels based on species and proximity. At a distance, a chorus can register 70 to 80 decibels (dB), comparable to a vacuum cleaner. Closer to a tree teeming with cicadas, the volume escalates dramatically, reaching 90 to 100 decibels. This is comparable to a lawnmower, blender, or motorcycle.
The African Brevisana brevis is the world’s loudest insect, recorded at 107 decibels from 20 inches away, similar to a chainsaw. In North America, certain species can reach 100 decibels or more. For perspective, 100 decibels is like a jackhammer or subway train. Though substantial, perceived loudness fluctuates as choruses ebb and flow.
The Biology Behind the Buzz
Male cicadas produce loud sounds using specialized tymbals. These are ribbed, drum-like membranes on the insect’s abdomen. Powerful internal muscles rapidly contract and relax, causing the tymbal membranes to buckle inward and then snap back, generating a series of rapid clicks.
This rapid vibration, up to 400 times per second, creates the continuous buzzing sound. The cicada’s hollow abdomen acts as a resonating chamber, amplifying the sound. This design, like a Helmholtz resonator, projects sound over distances. Its primary purpose is to attract female mates, but it also serves as a defense mechanism.
Living with the Loudness
Cicada noise impacts both insects and humans. For cicadas, loud songs are essential for species recognition and reproduction, as males congregate to attract females. The sheer volume helps their calls cut through environmental noise and reach potential mates.
For humans, the seasonal cicada chorus is a unique experience. While generally not harmful at typical listening distances, prolonged close exposure to sound levels above 85 decibels, like those from cicadas, can affect hearing. Some individuals find the constant noise annoying. Others, particularly those with tinnitus, may experience a temporary masking of their condition or an exacerbation of symptoms. To manage the sound, individuals can use earplugs or noise-canceling headphones, or limit time spent in heavily populated areas.