Why might prime-number cycles help them?

They rarely line up with predator cycles

What was special about 2024?

Two broods emerged together for the first time since 1803

What happens after adults mate?

Females lay eggs in twigs and adults die within weeks

Periodical Cicada Quiz: 13 and 17-Year Broods Underground

This periodical cicada quiz counts the years with North America's most patient insects. Play 10 interactive questions on 13-year and 17-year life cycles, nymphs feeding on root sap, prime numbers and predators, emerging when soil warms, broods numbered in Roman numerals, predator satiation, red eyes, the 2024 double emergence and what happens after mating.

Start Periodical Cicada Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Region
Where do periodical cicadas live?
Cycles
How long are their life cycles?
Under
What do nymphs feed on underground?
Prime
Why might prime-number cycles help them?
Trigger
What signals the nymphs to emerge?
Brood
How are periodical cicada groups named?
Numbers
How do huge numbers help them survive?
Eyes
What color are periodical cicada eyes?
2024
What was special about 2024?
After
What happens after adults mate?

Explanations: answer key for all 10 questions

Q1: Where do periodical cicadas live?
Answer: Eastern North America
They are unique to the region.
Q2: How long are their life cycles?
Answer: 13 or 17 years
Most of it is spent underground.
Q3: What do nymphs feed on underground?
Answer: Sap from tree roots
They suck it with mouthparts.
Q4: Why might prime-number cycles help them?
Answer: They rarely line up with predator cycles
It is a popular theory.
Q5: What signals the nymphs to emerge?
Answer: Soil warming to around 18 C
It happens in spring.
Q6: How are periodical cicada groups named?
Answer: Broods with Roman numerals
Brood X is famous.
Q7: How do huge numbers help them survive?
Answer: Predators cannot eat them all
This is predator satiation.
Q8: What color are periodical cicada eyes?
Answer: Red
They stand out against black bodies.
Q9: What was special about 2024?
Answer: Two broods emerged together for the first time since 1803
Broods XIII and XIX overlapped.
Q10: What happens after adults mate?
Answer: Females lay eggs in twigs and adults die within weeks
Nymphs drop to the soil.

Waiting 17 Years for Spring

Periodical cicadas of eastern North America spend most of their lives underground as nymphs, sucking sap from tree roots. Depending on the species, they emerge after 13 or 17 years. A popular theory says these prime-number cycles rarely line up with the shorter cycles of predators.

In spring of their final year, when the soil warms to around 18 C, nymphs dig out by the millions, climb trees and shed their skins. Adults have black bodies and red eyes. Their huge numbers overwhelm predators, which cannot eat them all, a strategy called predator satiation. Groups emerging in the same year are called broods, numbered in Roman numerals, such as Brood X.

Males sing in loud choruses, and after mating, females lay eggs in twigs. Adults die within weeks, and hatching nymphs drop to the soil to start the long wait again. In 2024, Broods XIII and XIX emerged together for the first time since 1803.

What This Quiz Teaches

Insect fans will enjoy these questions.

How long they wait
What nymphs eat
Why primes may matter
How broods work
What happened in 2024

Did You Know?

Emergence holes dot the ground.
Pets and birds feast on them.
Young trees can be damaged by egg laying.
Their shells pile up under trees.
Scientists use apps to map emergences.