Why do cicadas emerge every 13 to 17 years?

Cicadas emerge every 13 to 17 years as part of their life cycle strategy, known as "periodical cicadas." This phenomenon is exhibited by certain species of cicadas in North America. The extended life cycle is believed to be an adaptation that helps them avoid predators and synchronize their emergence.

The long period of development underground, either 13 or 17 years, is thought to be a strategy to minimize the overlap with the life cycles of their predators. This way, they can overwhelm predators by emerging in large numbers simultaneously, making it difficult for predators to consume all of them.

The synchronized emergence also increases the chances of successful mating. By emerging in massive numbers, cicadas can improve the likelihood of finding mates for reproduction. This strategy is said to be an example of evolutionary adaptation that enhances the survival and reproductive success of the species.