Cicadas are known for their distinctive buzzing sound, a common feature of summer landscapes. This natural phenomenon, while sometimes overwhelming, represents a sophisticated form of communication. Understanding the science behind this sound reveals intricate biological mechanisms. This article will explore how cicadas generate their calls, the various reasons behind their buzzing, and the environmental factors that influence their acoustic displays.
How Cicadas Produce Sound
Male cicadas produce their sounds using specialized organs called tymbals, located on the sides of their abdomen. Unlike crickets, cicadas use these ribbed membranes to create sound. Muscles attached to the tymbals contract rapidly, causing the membranes to buckle inward and then spring back, generating a series of rapid clicks. Each tymbal can vibrate hundreds of times per second, creating a continuous buzzing or whirring sound.
The cicada’s body design further enhances this sound. The abdomen of male cicadas is largely hollow, functioning as a resonant chamber that greatly amplifies the sounds produced by the tymbals. Internal air sacs and hollow tracheal tubes within their bodies also contribute to this amplification, allowing the initial clicks to become loud, far-reaching calls. This system enables them to achieve volumes audible over significant distances.
The Purpose Behind the Buzz
Cicadas primarily buzz for communication, with the male’s loud calls serving as a key part of their reproductive strategy. The most common and loudest sounds are mating calls, designed to attract females of the same species. Each cicada species possesses a unique song pattern, which helps prevent interspecies breeding and ensures successful reproduction.
Cicadas also produce different types of calls for various situations. Males may switch to a quieter, more refined courtship song when a female is nearby, signaling their intent to mate. If disturbed or captured, a cicada might emit a loud, erratic distress call, which can startle or deter predators. Additionally, some males use territorial calls to ward off other males and establish their space within a chorusing group.
Factors Influencing Cicada Sound
The loudness of cicada sounds, which can range from 80 to 115 decibels, stems from a combination of anatomical features and behavioral patterns. The efficient amplification system involving their hollow abdomen allows a single cicada to produce a powerful sound. When millions of cicadas emerge and synchronize their calls, the collective volume becomes even more intense, creating a widespread chorus that can be heard over a mile away.
Different cicada species, such as periodical and annual cicadas, exhibit distinct calls and emergence patterns, contributing to the diversity of sounds heard throughout the summer. For instance, some species produce a high-pitched whine, while others create a pulsating buzz or rhythmic clicks. Environmental factors also significantly influence cicada sound production. Warmer temperatures generally lead to increased activity and louder buzzing, as cicadas are cold-blooded and rely on ambient heat for optimal function.
Cicada activity is also affected by the time of day, with many species being most vocal during the warmest parts of the day. As temperatures rise, their muscles become more efficient, enabling more rapid tymbal vibrations. This sensitivity to temperature means that fluctuations in weather can impact when and how loudly cicadas buzz, shaping the acoustic landscape of their habitats.