Cicadas are large, distinctive insects famous for the loud, droning sound that fills the air during summer months. This unique acoustic presence often signals the arrival of the warmest part of the year. The question of how long this noise lasts has two very different answers, depending on whether one is asking about the daily cycle or the total seasonal duration of their adult life stage.
Why Cicadas Sing: The Purpose of the Noise
The sound is produced almost exclusively by the males of the species. This noise is a complex form of communication and serves as a species-specific mating call. Males generate the sound using a pair of specialized organs called tymbals, which are thin, ribbed membranes located on the sides of their abdomen.
The male rapidly contracts muscles attached to these tymbals, causing the membranes to buckle in and out hundreds of times per second. This vibration creates the loud, resonant sound, which is amplified by the cicada’s mostly hollow abdomen. Each species has a unique song, ensuring males attract only females of their own kind. The chorus also serves to establish territory and may act as a defense mechanism against predators like birds.
Daily Noise Limits and Environmental Factors
Cicadas are diurnal, meaning their singing is strongly tied to sunlight and warm temperatures. The insects are cold-blooded, relying on the environment to regulate their body temperature. Their sound-producing muscles only function when they are sufficiently warm.
Most species require the ambient temperature to reach or exceed a minimum threshold, often around 72°F (22°C), before they begin their chorus. The noise typically peaks during the hottest part of the day, when the insects are most active. As the sun begins to set and temperatures drop, the cicada chorus rapidly diminishes. The noise ceases entirely by sundown, offering a reprieve from the daytime buzz.
Seasonal Duration of an Adult Emergence
The total seasonal duration of the noise depends on the type of cicada present in a given region. There are two primary groups: annual cicadas and periodical cicadas.
Annual Cicadas
Annual cicadas, sometimes called Dog-day cicadas, are heard every summer because their life cycles are staggered. This means a small number of adults emerge each year. The underground nymph stage for these species lasts between two and five years. Their sound is typically heard throughout the summer months, beginning in July and continuing until September, providing a consistent summertime soundtrack. The emergence is not synchronized, resulting in a low but constant presence of singing adults.
Periodical Cicadas
Periodical cicadas are known for their spectacular, synchronized emergences that occur only every 13 or 17 years. The noise from these broods is far louder and more intense than the annual species due to the sheer number of insects emerging at once. However, the duration of this massive noise event is short-lived. The entire above-ground adult phase typically lasts only four to six weeks. The mass emergence usually begins in late April or May and concludes by late June or early July. This intense, loud period ends abruptly as the short adult lifespan concludes, leaving silence until the next synchronized emergence years later.
What Happens When the Noise Stops
The cessation of the cicada chorus marks the end of the adult reproductive stage and the beginning of the next generation’s subterranean life. The adult cicadas have a lifespan above ground of only a few weeks, just enough time to mate and lay eggs. Shortly after completing reproduction, all the adults die.
Female cicadas lay their eggs in small slits they cut into the bark of young tree branches. After six to ten weeks, the eggs hatch, and the tiny nymphs drop to the ground below. These nymphs immediately burrow into the soil, where they locate and feed on the sap from tree roots. This begins the long phase of the cicada life cycle, which lasts for years or over a decade, depending on the species. The insects live silently as nymphs until environmental signals trigger the next emergence and the return of their summer song.