Quick Facts About 13-Year Periodical Cicada Behavior

Periodical cicadas are among the most fascinating and enigmatic insects in the natural world. Known for their striking emergence patterns and unique life cycles, these insects draw attention every time they surface. Among the different types of periodical cicadas, the 13-year variety is especially intriguing due to its relatively rare emergence and distinctive behaviors. This article explores quick facts about the 13-year periodical cicada behavior, shedding light on their life cycle, emergence, mating habits, and ecological impact.

What Are 13-Year Periodical Cicadas?

Periodical cicadas belong to the genus Magicicada. They are characterized by their long nymphal development stages underground, lasting either 13 or 17 years. The 13-year cicadas are one of the two major groups distinguished by their synchronized emergence every 13 years.

These cicadas spend most of their lives underground as nymphs, feeding on sap from tree roots. When it is time to emerge, they do so in large numbers simultaneously, a phenomenon known as “periodic mass emergence.”

Life Cycle of 13-Year Periodical Cicadas

The life cycle of a 13-year periodical cicada can be divided into several distinct stages:

1. Egg Stage

Adult female cicadas lay their eggs in slits cut into small branches or twigs of trees and shrubs. Each female can lay hundreds of eggs during her lifetime.

2. Nymph Stage

Once the eggs hatch, tiny nymphs drop to the ground and burrow underground. They attach themselves to the roots of trees and plants and begin feeding on xylem fluid. This subterranean stage lasts precisely 13 years.

3. Emergence

After completing their development, the nymphs tunnel to the surface simultaneously in massive numbers. This synchronous emergence typically occurs in late spring or early summer when soil temperatures reach around 64°F (18°C).

4. Molting and Adult Stage

Upon surfacing, nymphs climb nearby vegetation and molt one final time, emerging as winged adults. Their characteristic red eyes and orange-veined wings become visible once their exoskeleton hardens.

5. Mating and Death

Adults live only about four to six weeks above ground. During this time, males attract females with loud choruses of mating calls. After mating, females lay eggs for the next generation before dying off.

Behavior During Emergence

Synchronous Mass Emergence

One of the most remarkable aspects of 13-year periodical cicadas is their synchronized mass emergence that occurs in vast numbers over a short period—usually within a few weeks. This overwhelming population size is an evolutionary survival strategy known as predator satiation. By emerging en masse, they reduce individual predation risk since predators cannot consume all cicadas at once.

Nocturnal and Diurnal Activity

While many insects are strictly nocturnal or diurnal, periodical cicadas exhibit activity during both day and night but tend to be more vocally active during daylight hours. Males use species-specific calls to stake out territories and attract mates.

Calling Behavior

Male cicadas produce loud mating calls using specialized structures called tymbals located on the sides of their abdomens. These calls can reach up to 100 decibels—comparable to a motorcycle engine—and vary among different broods and species.

The collective chorus creates a unique soundscape that signals readiness for reproduction and helps females locate suitable mates across dense forest canopies.

Social Interactions

Unlike many solitary insects, periodical cicadas display interesting social behaviors during their brief adult phase:

• Aggregation: Adults cluster on tree trunks and branches in large groups.
• Territoriality: Males exhibit territorial behavior by defending calling sites from rivals.
• Mate Selection: Females choose mates based on call characteristics like frequency and duration, which indicate male fitness.

Ecological Impact

Periodical cicadas have profound effects on ecosystems during their emergence years:

Nutrient Cycling

When millions of cicadas die after reproduction, their decomposing bodies provide a significant nutrient boost to soil ecosystems. This pulse of nitrogen and other nutrients supports plant growth and benefits microorganisms.

Predator Food Source

The sudden abundance of cicadas provides a feast for birds, mammals, reptiles, amphibians, and other arthropod predators. This temporary food bonanza can lead to population increases in some predator species.

Tree Pruning

Egg-laying females cut small slits into twigs to deposit eggs; while this can cause minor damage called “flagging,” it generally does not seriously harm healthy trees but may prune weaker branches.

Geographic Distribution

The 13-year periodical cicada broods are primarily found in parts of the eastern United States including states such as:

• Illinois
• Indiana
• Kentucky
• Tennessee
• Missouri
• Arkansas
• Mississippi
• Alabama

Different broods emerge in varying years within these regions according to established cycles.

Identifying Features

Some quick identifying features of 13-year periodical cicadas include:

• Red Eyes: One of their most recognizable traits.
• Black Bodies: With orange wing veins.
• Size: Adults measure about 1 to 1.5 inches in length.
• Sound: Loud buzzing chorus distinctive from other cicada species.

Why Do They Have a 13-Year Cycle?

Scientists theorize that having prime-numbered life cycles (like 13 or 17 years) reduces chances of synchronizing with predators that have shorter reproductive cycles. This prime number strategy minimizes overlap with predator population peaks and enhances survival odds through predator satiation tactics.

Threats to Periodical Cicadas

While they appear resilient due to mass emergences, several factors can threaten local populations:

• Habitat Loss: Urbanization reduces suitable tree habitats.
• Climate Change: Altered temperature patterns may disrupt emergence timing.
• Pollution: Pesticides and pollutants impact survival rates.
• Predation: Despite predator satiation, localized predation pressure can affect smaller broods.

Conservation efforts focus on preserving natural habitats and minimizing pesticide use during emergence periods.

Interesting Scientific Studies

Recent studies have explored topics such as:

• Genetic differences between broods.
• Variations in calling songs linked to geographic distribution.
• Effects of climate change on emergence timing shifts.
• Role of microbial symbionts in underground nymph development.

These ongoing research efforts help deepen understanding of periodical cicadas’ ecology and evolution.

Conclusion

The behavior of 13-year periodical cicadas is a captivating example of nature’s complexity—from their precise life cycle timing to their social calling behaviors above ground. Their ability to synchronize mass emergences after spending over a decade underground exemplifies an extraordinary survival strategy rooted in evolutionary history.

This insect’s role within ecosystems as nutrient recyclers and prey further emphasizes how interconnected life systems depend on even the most unlikely creatures. Whether you encounter a brood during its fleeting appearance or read about them fascinated by their biology, periodical cicadas remind us just how remarkable insect behavior can be.

Understanding these facts provides not only appreciation but also encourages efforts toward conserving these natural wonders for future generations to witness every thirteen years anew.