If you’ve ever been outside during summer and heard an incredibly loud buzzing sound coming from the trees, you’ve probably encountered cicadas. These fascinating insects are some of the loudest creatures on Earth, and understanding how cicadas make noise reveals one of nature’s most amazing sound systems.
What Makes Cicadas So Loud
Cicadas are among the loudest insects in the world, with some species reaching up to 120 decibels. That’s about as loud as a chainsaw or standing next to a jet engine! To put this in perspective, a normal conversation is around 60 decibels, while a lawnmower runs at about 90 decibels.
The loudest group of cicadas are the periodical ones that emerge every 13 years and those that appear every 17 years, probably because there are so many more of them than the annual ones. When millions of these insects sing together, the sound can be heard from over a mile away.
The Tymbal Organ Creates the Sound
So how exactly do cicadas make noise? The secret lies in special organs called tymbals. Cicadas produce their loud buzzing or clicking noises through specialized structures called tymbals, which are located on their abdomens. The tymbals are regions of the exoskeleton that are modified to form a complex membrane with thin, membranous portions and thickened “ribs”.
Think of these tymbals like tiny drums built right into the cicada’s body. Each male cicada has a pair of these circular ridged membranes on the back and side surface of the first abdominal segment.
How the Clicking Mechanism Works
The way cicadas make noise is pretty clever. When a cicada contracts these muscles, the tymbals buckle inward rapidly, creating a clicking sound. Picture pressing down on the center of a metal bottle cap until it pops inward.
Each rib undergoes a sudden deformation from a convex to a V-shaped profile when buckling occurs. The tymbal springs back when the muscle is relaxed, creating another click as it snaps back to its original shape. This buckling and snapping motion happens incredibly fast.
Rapid Fire Creates Continuous Sound
Here’s where things get really amazing. The cicada repeats the action 300 to 400 times per second, creating the characteristic crescendoing drone. The frequency of the contractions of the tymbal muscle range from 120 to 480 times a second, which is fast enough to make it sound continuous to the human ear.
During the sound-making process, the ribbed membranes are contracted and released at a high frequency (300-400 times per second). Many clicks produce a buzzing sound because our ears can’t pick up each individual click when they happen so quickly.
The Body Amplifies the Sound
The tymbal organs alone wouldn’t make cicadas nearly as loud as they are. The real volume comes from how their bodies work like natural amplifiers. The abdomen of male cicadas are almost completely hollow, functioning as a natural resonance chamber. It’s similar to how a guitar’s hollow body makes the strings sound much louder.
Cicadas also have air sacs that have resonant frequencies comparable to tymbal vibration frequencies, thus amplifying the sound. The abdomen of male cicadas forms a Helmholtz resonator, the components of which are the large air sac as the cavity and the tympana as the neck of the resonator. This setup allows the small clicks from the tymbals to become the booming sounds we hear.
Different Species Make Different Sounds
Not all cicadas sound the same. Different species have different characteristic calling songs. The call of decim periodical cicadas is said to resemble someone calling “weeeee-whoa” or “Pharaoh”, while the cassini and decula periodical cicadas have songs that intersperse buzzing and ticking sounds.
Different cicada species produce unique sounds, patterns, and frequencies. Some sound like high-pitched whines, others make rhythmic pulses, and some create sounds that almost seem musical. Understanding how cicadas make noise helps explain why each species has developed its own unique “song.”
Only Males Make the Famous Cicada Sound
Here’s an interesting fact: The sound is produced only by males, mostly for the reasons you might imagine. The loud buzzing or clicking cicada noise is produced by male cicadas as a form of courtship to attract females for mating. The males are basically singing love songs to attract girlfriends!
Females also make sounds to attract males, but they use their wings to make a clicking sound, rather than a high-pitched song like the males. So when you hear that loud summer buzzing, you’re listening to male cicadas trying to impress the ladies.
Temperature Controls When They Sing
Weather plays a huge role in when cicadas make noise. The songs of the cicada are affected by weather fluctuations. Generally speaking, cicadas like sunlight and warmth, but too much heat or too much coolness will quiet them down a bit. Cicadas only emerge when the soil is warm, typically a relatively toasty 64 degrees Fahrenheit.
The peak time for their vocal activities is typically during the hottest parts of the day, from late morning until the late afternoon. This is why you’ll notice cicadas get quiet during cool, rainy weather and become loudest on hot, sunny days.
Multiple Purposes for Cicada Calls
Cicadas make noise for several different reasons. There are congregational songs, in which males synchronize their calls. The choruses establish territory and attract females. In addition, there is a courting call that is usually produced prior to copulation.
Males of each species typically have three distinct sound responses: a congregational song, a courtship song, and a disturbance squawk produced by individuals captured, held, or disturbed into flight. So they have different “songs” for attracting mates, claiming territory, and warning others when they’re in danger.
Annual vs Periodical Cicada Differences
There are two main types of cicadas, and they have different patterns for when they make noise. The annual cicadas are species that emerge every year, though these cicadas’ life cycles can vary from 1 to 9 or more years as underground nymphs. These are the ones you probably hear every summer.
One exclusively North American genus, Magicicada (the periodical cicadas), emerge in predictable intervals of 13 or 17 years. Periodical cicadas are a little bigger than annual cicadas and are dark in color with bright red eyes and orange coloring on their legs and wing veins. When the periodical cicadas emerge, they create an absolutely incredible wall of sound that can be overwhelming.
Why Loud Sounds Help Survival
You might wonder why cicadas make noise so loudly when it seems like it would just attract predators. But there’s actually a smart survival strategy behind all that racket. One theory for why the songs are so loud is that the songs may deter predators. The sheer volume can actually be painful or startling to birds and other animals that might want to eat them.
The unusual duration and synchronization of their emergence may reduce the number of cicadas lost to predation, both by making them a less reliably available prey and by emerging in such huge numbers that they will satiate any remaining predators. The cicadas are hedging their bets by showing up in such huge numbers, hoping this will guarantee a sustainable number of new cicadas will successfully be born. It’s like safety in numbers, but with volume turned up to eleven.
Understanding how cicadas make noise shows us just how amazing these creatures really are. From their specialized drum-like organs to their built-in amplification systems, cicadas have evolved one of the most effective sound-producing mechanisms in the natural world. The next time you hear that familiar summer buzzing, you’ll know you’re listening to one of nature’s most impressive concerts.
