Ah, summer. That wonderful season when the sun shines brightly, and nature is in full swing. It’s also the time when you might find yourself asking: “Why do cicadas make so much noise?” The buzzing of cicadas can be incredibly loud, sometimes making it difficult to hear anything else. But there’s a fascinating reason behind this summer soundtrack.
In North America, the most common noisy cicadas are often called dog-day cicadas. These, along with other cicada species around the globe, create their distinctive sounds for very specific reasons, all primarily driven by the males. Just like birds sing or frogs croak, male cicadas produce their loud calls to attract females and establish their territory. They even have ‘congregational songs’ where groups of males synchronize their calls, creating an even louder chorus. Think of it as a summer concert, but for attracting a mate! There’s also a softer ‘courting call’ that males use when they’re closer to a female, ready for mating. Interestingly, the weather can influence their singing – cicadas generally love sunlight and warmth, but extreme heat or cold will quiet them down. Different cicada species also have their preferred times of day to sing, and each of the thousands of species has its own unique song.
One theory suggests that the sheer volume of their songs might actually help protect them from predators. The loudest cicadas of all are the periodical cicadas, famous for emerging in massive numbers every 13 or 17 years. Their overwhelming numbers and deafening chorus are thought to confuse or deter potential predators.
But how do these insects create such a powerful sound? Cicadas possess a special organ called a tymbal, almost unique in the insect world. Male cicadas each have a pair of these tymbals, which are circular, ridged membranes located on their abdomen.
The magic happens when a tymbal muscle, attached to this membrane, contracts. This contraction causes the tymbal to buckle inwards, producing a click sound. When the muscle relaxes, the tymbal springs back, creating another click. This muscle contracts and relaxes incredibly rapidly, between 120 to 480 times per second! This rapid clicking is so fast that it sounds like a continuous buzz to our human ears. To amplify the sound even further, cicadas have air sacs in their bodies that resonate at frequencies similar to the tymbal vibrations. These air sacs act like natural amplifiers, boosting the sound to create that characteristic, loud, high-pitched buzzing that we associate with late summer.
So, the next time you hear the loud buzzing of cicadas, remember it’s more than just noise. It’s a complex form of communication, a summer serenade played out across nature’s stage, all thanks to a remarkable organ and a very important mission: to find a mate and continue the cycle of life.
