Why Do Scientists Think It Is Helpful to the Periodical Cicadas to Emerge Every 13 to 17 Years?

Nature is full of mysteries, and one of the most fascinating ones is the life cycle of periodical cicadas. These insects spend most of their lives underground, only to emerge once every 13 or 17 years. But why do scientists think it is helpful to the periodical cicadas to emerge every 13 to 17 years? This unique survival strategy has puzzled researchers for years. Scientists believe that this unusual timing helps cicadas avoid predators, maximize reproduction, and take advantage of environmental conditions.

In this blog, we will explore the reasons why this rare and incredible phenomenon happens and why it is so beneficial for cicadas.

Also read: What Is the Driving Force Behind Lifelong Learning and Adaptability?

The Survival Strategy Behind the 13- and 17-Year Cycle

One of the biggest reasons cicadas emerge in long cycles is to avoid predators. If cicadas came out every year, birds, spiders, and other predators would learn to rely on them as a food source. However, since cicadas only emerge after more than a decade, no predator can build a consistent population based on eating them. This means that when cicadas finally appear, they do so in massive numbers, overwhelming any predators that might try to eat them. Scientists call this "predator satiation." Essentially, there are so many cicadas at once that predators can only eat a small fraction of them, leaving the rest to reproduce and continue the cycle.

Prime Numbers and Predator Confusion

Another fascinating reason cicadas emerge every 13 or 17 years is that these numbers are prime numbers. A prime number is a number that cannot be divided evenly by anything other than 1 and itself. Scientists believe this is important because it prevents cicadas from syncing up with the life cycles of potential predators. For example, if cicadas emerged every 12 years, a predator with a life cycle of 2, 3, 4, or 6 years could eventually match up with them. But because 13 and 17 are prime numbers, it is much harder for predators to align their life cycles with the cicadas, giving the insects a better chance of survival.

Avoiding Competition for Resources

Cicadas depend on tree roots for food while they are underground. If they emerged too often, they might harm the trees they rely on. By staying underground for long periods, cicadas allow trees to recover and regrow, ensuring that future generations of cicadas will have enough nutrients to survive. This long development time also means that when cicadas finally come out, the environment has had enough time to replenish, giving them the best possible chance to thrive.

Climate and Temperature Play a Role

Scientists also believe that cicadas time their emergence based on temperature changes. Periodical cicadas only come out when the soil reaches a certain temperature, usually around 64°F (18°C). This means they are more likely to appear during warm seasons when food is abundant, and the chances of successful reproduction are high. By using temperature as a cue, cicadas can ensure they emerge at the right time for survival.

The Mass Emergence Advantage

When cicadas finally come out, they do so in massive numbers. This is another way to increase their survival chances. This strategy, known as "predator satiation," means that even if predators eat a lot of cicadas, there will still be enough left to mate and lay eggs. Because cicadas emerge in the millions, predators quickly become full and stop eating, allowing most of the cicadas to survive and reproduce.

How Cicadas Benefit the Environment

While cicadas might seem like a nuisance when they appear in huge swarms, they actually play an important role in the ecosystem. When cicadas die, their bodies provide nutrients for the soil, helping trees and plants grow. Their emergence also helps aerate the soil, improving its health. Additionally, their feeding on tree roots while underground stimulates tree growth over the long term. So, while their presence might seem overwhelming, they are actually helping the environment in many ways.

Conclusion

So, why do scientists think it is helpful to the periodical cicadas to emerge every 13 to 17 years? The answer lies in survival, reproduction, and nature’s balance. By using prime-numbered life cycles, cicadas avoid predators and competition, ensuring their species continues to thrive. Their unique timing allows them to emerge when conditions are perfect, and their massive numbers protect them from being wiped out by predators. Cicadas may be one of nature’s strangest insects, but their strategy is a remarkable example of how life finds a way to persist and succeed. The next time you see or hear a swarm of cicadas, remember that they have waited over a decade for their moment in the sun, and their emergence is one of nature’s most brilliant survival tricks.