Why are they called periodical cicadas

          

Introduction:

Every 17 years, like clockwork, certain regions of North America become inundated with the deafening buzz of periodical cicadas. These remarkable insects, known for their synchronized emergence in massive numbers, have puzzled scientists and intrigued nature enthusiasts for centuries. What drives these cicadas to appear in such precise intervals, and what purpose does their unique life cycle serve? In this article, we delve into the fascinating world of periodical cicadas to uncover the secrets behind their enigmatic behavior.

 

1. The Phenomenon of Periodical Cicadas:

   Periodical cicadas belong to the genus Magicicada and are divided into several broods, each with its distinct emergence pattern. The most well-known broods include Brood X, which emerges every 17 years, and Brood XIII, which emerges every 13 years.

   These cicadas spend the majority of their lives underground as nymphs, feeding on sap from tree roots. After precisely 17 or 13 years, depending on the brood, they emerge from the ground in vast numbers to undergo metamorphosis into their adult form.

   The synchronized emergence of periodical cicadas is one of the most remarkable phenomena in the insect world, attracting attention from scientists, naturalists, and curious observers alike.

 

2. Evolutionary Adaptations:

   The extended life cycle of periodical cicadas is believed to be an evolutionary adaptation to avoid predators and minimize competition for resources. By emerging in large numbers at infrequent intervals, they overwhelm predators with their sheer numbers, ensuring that enough individuals survive to reproduce.

   The prime-numbered intervals of 17 and 13 years are thought to provide additional protection against predators, as these intervals are less likely to coincide with the life cycles of potential predators.

   Additionally, the long development period spent underground allows periodical cicadas to synchronize their emergence with specific environmental cues, such as soil temperature and moisture levels, ensuring optimal conditions for survival.

 

3. Mating Behavior and Reproduction:

   Once above ground, male cicadas produce their characteristic buzzing mating calls to attract females. The cacophonous chorus created by millions of male cicadas can reach deafening levels, signaling the peak of the cicada emergence phenomenon.

   After mating, females deposit their eggs in the branches of trees, where they hatch into tiny nymphs and drop to the ground below. These nymphs burrow into the soil, beginning the cycle anew and disappearing from sight for another 17 or 13 years.

 

4. Ecological Impact:

   The emergence of periodical cicadas has significant ecological implications, influencing nutrient cycling, forest dynamics, and food webs. As nymphs feed on tree roots, they contribute to soil aeration and nutrient redistribution.

   When adult cicadas emerge in massive numbers, they provide a plentiful food source for a wide range of predators, including birds, mammals, and insects. This influx of nutrients can have cascading effects throughout the ecosystem, influencing population dynamics and community structure.

   Additionally, the egg-laying behavior of female cicadas can cause damage to tree branches, particularly in orchards and ornamental landscapes, although this damage is typically temporary and does not pose a long-term threat to tree health.

 

Conclusion:

The mystery of why some cicadas appear only every 17 years continues to captivate scientists and nature enthusiasts alike. Through their remarkable life cycle, periodical cicadas have evolved to maximize their chances of survival and reproduction, while also exerting a profound influence on the ecosystems they inhabit. By studying these fascinating insects, researchers gain valuable insights into the intricate workings of nature and the complex interplay between species and their environment.