Periodical cicadas are among the most fascinating insects in the natural world, known for their unique life cycles and synchronized emergence. When people ask how long do periodical cicadas live, the answer may seem surprising because these insects spend most of their lives underground. Unlike many other insects that live only a few months or years, periodical cicadas have one of the longest life cycles in the insect world. Their lives are divided into two main stages a long underground phase and a short above-ground adult phase. Understanding how long periodical cicadas live helps us appreciate their role in ecosystems and the remarkable nature of their development.
What Are Periodical Cicadas?
Periodical cicadas are a group of insects known for emerging in large numbers after spending many years underground. They belong to the genus Magicicada and are mostly found in North America.
These cicadas are different from annual cicadas, which appear every year. Periodical cicadas follow a strict life cycle, emerging every 13 or 17 years depending on the species.
Main Characteristics
- Large groups emerging at the same time
- Red eyes and black bodies
- Transparent wings
- Distinctive loud mating calls
Their synchronized emergence makes them one of the most noticeable insect events in nature.
How Long Do Periodical Cicadas Live?
The total lifespan of periodical cicadas can range from 13 to 17 years, depending on the species. This long lifespan is what makes them unique among insects.
However, it is important to understand that most of this time is spent underground in the nymph stage. The adult stage, when they are visible above ground, lasts only a few weeks.
Life Cycle Breakdown
- Underground nymph stage 13-17 years
- Above-ground adult stage 4-6 weeks
This means that while periodical cicadas live for many years, most of their life is hidden from view.
The Underground Life Stage
The majority of a periodical cicada’s life is spent underground as a nymph. During this stage, the insect feeds on the sap from tree roots and slowly grows and develops.
This stage is essential for their survival and development, even though it is not visible to humans.
Key Activities Underground
- Feeding on plant roots
- Growing and molting
- Staying protected from predators
- Developing into adults
The long underground phase helps protect cicadas from environmental dangers and allows them to emerge in large numbers later.
The Emergence Phase
After spending 13 or 17 years underground, periodical cicadas emerge from the soil in massive groups. This event is often called a brood emergence.
The timing of this emergence is highly synchronized, meaning millions of cicadas appear at the same time in a specific region.
What Happens During Emergence
- Cicadas climb out of the ground
- They shed their exoskeletons (molting)
- Wings expand and harden
- Adults begin their short above-ground life
This stage marks the beginning of their reproductive period.
The Adult Life Stage
The adult stage of periodical cicadas is very short compared to their total lifespan. Once they emerge, adult cicadas live for only about 4 to 6 weeks.
During this time, their main goal is to reproduce and continue the species.
Adult Cicada Activities
- Finding mates
- Laying eggs in tree branches
- Producing loud mating calls
- Completing their life cycle
After laying eggs, the adult cicadas die, and the next generation begins its underground journey.
Why Do They Live So Long?
One of the most interesting questions about periodical cicadas is why they live for such a long time. Scientists believe there are several reasons for their extended lifespan.
Possible Reasons
- Predator avoidance through synchronized emergence
- Survival strategy based on prime-number life cycles (13 and 17 years)
- Reduced competition for resources
- Environmental adaptation
Living underground for many years helps them avoid predators and increases their chances of survival as a species.
Life Cycle Strategy
The life cycle of periodical cicadas is a survival strategy that benefits them in several ways. By emerging all at once, they overwhelm predators, ensuring that enough individuals survive to reproduce.
This strategy is known as predator satiation.
Advantages of This Strategy
- Reduces the impact of predators
- Increases chances of reproduction
- Ensures species survival
- Creates a natural balance in ecosystems
This unique strategy helps explain how long periodical cicadas live and why their life cycle is so unusual.
Broods and Geographic Distribution
Periodical cicadas are grouped into broods, which are populations that emerge in specific years and locations. Each brood has its own cycle, either 13 or 17 years.
These broods are identified by numbers and are spread across different regions.
Brood Characteristics
- Each brood emerges in a specific cycle
- Some broods are 13-year cicadas
- Others are 17-year cicadas
- Found in different geographic areas
This system helps scientists study and track cicada populations.
Environmental Role of Cicadas
Periodical cicadas play an important role in the environment. Even though they live underground for most of their lives, their emergence has a significant impact on ecosystems.
Environmental Contributions
- Provide food for birds and animals
- Help aerate the soil
- Contribute nutrients when they die
- Support tree and plant growth
Their life cycle helps maintain balance in nature.
Difference from Annual Cicadas
Not all cicadas are periodical. Annual cicadas have shorter life cycles and appear every year. Understanding the difference helps clarify how long periodical cicadas live.
Comparison
- Periodical cicadas 13 or 17 years
- Annual cicadas 2 to 5 years
- Emergence Synchronized vs. continuous
- Life cycle Long underground phase vs. shorter cycles
This difference highlights the uniqueness of periodical cicadas.
Human Interaction with Cicadas
Periodical cicadas are generally harmless to humans. They do not bite or sting and are not considered pests, although their large numbers can be overwhelming.
However, they can sometimes cause minor damage to trees when laying eggs.
Common Observations
- Loud buzzing sounds during mating season
- Cicadas covering trees and surfaces
- Temporary impact on landscaping
- Interesting natural event for observers
Many people find their emergence fascinating and unique.
So, how long do periodical cicadas live? The answer is that they live for 13 or 17 years, depending on the species, but most of that time is spent underground. Their brief life above ground lasts only a few weeks, during which they reproduce and complete their life cycle.
Their long lifespan, unique survival strategy, and synchronized emergence make periodical cicadas one of the most remarkable insects in nature. By understanding their life cycle, we can better appreciate their role in ecosystems and the complexity of the natural world.