What is unique about the life cycle of periodical cicadas?

What is unique about the life cycle of periodical cicadas?

• A. They spend 2-3 years underground as nymphs.
• B. They spend 13 to 17 years underground as nymphs before emerging to mate and die shortly after.
• C. They spend their entire life as adults.
• D. They spend 5-7 years underground as nymphs before emerging.

Answer: (B)

Periodical cicadas are defined by a long, synchronized juvenile stage followed by a brief adult phase. The key idea is that most of their life is spent underground as nymphs feeding on the roots of trees, and this underground period lasts a fixed, lengthy time—13 or 17 years depending on the brood. After this extended subterranean phase, they emerge all at once in spring as winged adults, mate, lay eggs, and then die within a few weeks. That combination of a very long underground life and a short, mass-emergence adult period is what makes their life cycle unique.