The quintessential sound of summer in many parts of the world is the distinct, reverberating hum of cicadas. These remarkable insects, known for their exceptionally loud “singing,” have intricate life cycles and a significant cultural presence. They are more than just noisy bugs; they are a symbol of the season itself. This exploration delves into the fascinating biology, surprising history, and practical considerations associated with these iconic creatures.

What Are Cicadas?

Cicadas belong to the superfamily Cicadidae, which includes over 3,000 known species around the globe. These notably loud insects have been a fixture in North America for millions of years.

The Fascinating Life Cycle of Cicadas

The life of a cicada begins underground. As nymphs, they spend a prolonged period—anywhere from one to 17 years—feeding on sap from tree roots. Once they mature, the nymphs emerge from the soil, climb a nearby tree, and shed their old exoskeletons one last time. This transforms them into winged adults. The discarded skins you often see clinging to tree trunks are tangible evidence of this incredible transition. The adult phase is remarkably brief, lasting only a few weeks to a single season. During this time, their primary goal is to mate and lay eggs.

Periodical vs. Annual Cicadas

We can broadly categorize cicadas into two main groups based on their emergence patterns.

  • Periodical Cicadas (Magicicada): These species emerge in massive, synchronized swarms every 13 or 17 years. Brood X is a famous example.
  • Annual Cicadas (Dog-Day Cicadas): As their name suggests, these species emerge every year. However, their individual nymphs still spend multiple years developing underground.

The Unmistakable Sound of Cicadas: How They “Sing”

The characteristic “singing” of cicadas is a unique biological feat.

The Sound-Producing Mechanism

The sound does not come from vocal cords. Instead, male cicadas have specialized organs called tymbals on their abdomens. A thick set of muscles rapidly contracts, pulling these ribbed membranes inward at an astonishing rate of 300 to 400 times per second. Each contraction creates a distinct click. The cicada’s hollow abdomen acts as a resonance chamber, amplifying these clicks into the loud, sustained buzz we recognize.

The Purpose and Incredible Volume of Cicada Songs

The primary purpose of the male cicada’s song is to attract female mates. This serenade can reach remarkable volumes, often registering between 90 and 100 decibels—as loud as a lawnmower. To protect their own hearing from such intense sound, male cicadas can temporarily crease their eardrums, effectively deafening themselves while they sing.

The Diverse Sounds of Different Cicada Species

While we often describe their song as a drone or buzz, cicadas produce a variety of sounds. Females respond to males by clicking their wings, a much more subtle sound. In addition, cicadas emit a distinctive “squawk” when handled or disturbed. Each species has a unique song pattern, which prevents inter-species mating.

The Science Behind the Swarm

The synchronized emergence of periodical cicadas is a crucial survival strategy. This mass appearance, known as predator satiation, overwhelms local predators. There are simply too many cicadas for them to eat, which ensures enough survive to reproduce.

Are Cicadas a Nuisance or a Natural Wonder?

Harmless to Humans and Pets

Despite their sometimes alarming appearance and overwhelming numbers, cicadas are generally harmless to humans and pets. They do not bite or sting and are largely defenseless.

Their Important Environmental Contributions

Cicadas provide several ecological benefits.

  • Soil Aeration: Their tunneling as nymphs helps aerate the ground.
  • Food Source: Emerging in vast quantities, they become an abundant food source for a wide array of predators, including birds, bats, reptiles, and mammals.
  • Nutrient Cycling: When they die, their decomposing bodies return valuable nutrients to the soil.

The “No Natural Predators” Myth Clarified

The idea that cicadas have no natural predators is a common misconception. While their long and unpredictable emergence cycles prevent the evolution of specialist predators (animals that rely solely on them for food), they are indeed eaten by many generalist predators.

Cicadas in Culture and History: A Timeless Hum

For millennia, human societies have recognized the cicada’s song as an iconic sound of summer.

  • In Ancient Greece, they were revered as symbols of immortality.
  • Ancient China held them in high esteem, considering them noble and humble. Jade cicadas were even placed in the mouths of the dead to symbolize resurrection.
  • In Japan, their sound is frequently used in films and anime to instantly signal the arrival of summer.

Experiencing the Emergence of Cicadas

During a mass emergence, you should expect an overwhelming presence of cicadas. They will be everywhere, and their discarded exoskeletons can accumulate to depths of several inches. While the noise can be considerable, it is a temporary and fascinating natural event.

For those interested in recording the sounds, it is best to wait until July when temperatures are consistently hot. This is when cicadas are most active and less inhibited.

Conclusion: Appreciating Nature’s Grand Chorus

Cicadas, with their distinctive sounds and complex life cycles, represent a truly remarkable natural phenomenon. Their synchronized emergences and deafening choruses are not just summer background noise; they are a testament to intricate evolutionary strategies. By understanding the science behind their symphony and their multifaceted impact, we can cultivate a deeper appreciation for these fascinating insects and the fleeting yet powerful grandeur of nature.