How to Identify Different Broods of 13-Year Periodical Cicadas

Periodical cicadas are among the most fascinating insects in North America, known for their extraordinary life cycles and synchronized emergences. Of particular interest are the 13-year periodical cicadas, which appear in large numbers every 13 years, captivating enthusiasts, scientists, and nature lovers alike. Identifying the different broods of these cicadas is an essential task for entomologists, researchers, and hobbyists who want to understand their distribution, behavior, and ecological impact. This article explores how to identify the different broods of 13-year periodical cicadas, detailing their characteristics, emergence patterns, geographic locations, and practical tips for observation.

Understanding 13-Year Periodical Cicadas

Before delving into brood identification, it’s crucial to understand what makes 13-year periodical cicadas unique. These cicadas belong primarily to the genus Magicicada, with three species groups known for their synchronized emergences:

Magicicada tredecim
Magicicada tredecula
Magicicada neotredecim

Unlike annual cicadas, which appear every year in various regions, periodical cicadas spend the vast majority of their lives underground as nymphs feeding on sap from tree roots. After either 13 or 17 years, they emerge simultaneously in enormous numbers to mate and lay eggs before dying shortly after.

What Are Broods?

A brood is a population of periodical cicadas that emerges simultaneously in a specific geographic area and year. Each brood has a designated Roman numeral (e.g., Brood XIX) and is either a 13-year or 17-year cycle group. For 13-year cicadas, there are fewer broods compared to the 17-year varieties. These broods are often geographically distinct but sometimes overlap.

The study and tracking of these broods help scientists better understand cicada ecology and evolution as well as predict future emergences.

Known 13-Year Broods

Currently, there are three confirmed major broods of 13-year periodical cicadas:

Brood XIX – Known as “Great Southern Brood”
Brood XXII
Brood XXIII

Each of these broods emerges once every 13 years but in different years and regions. Let’s examine each brood in detail.

Brood XIX (Great Southern Brood)

Geographic Range: This brood is widespread across parts of the southeastern United States including Louisiana, Mississippi, Alabama, Georgia, South Carolina, Tennessee, Arkansas, and parts of Florida.
Emergence Years: Most recently emerged in 2011 and then again in 2024.

Identification Features: Like other Magicicada species, the cicadas have distinctive black bodies with red eyes and orange wing veins.
Behavioral Traits: The males produce loud chorus songs to attract females; this brood is one of the most populous 13-year broods observed.

Brood XXII

Geographic Range: Found mainly in parts of Texas and Oklahoma.

Emergence Years: Emerged in 2009 and will next emerge in 2022.
Identification Features: Similar morphology to Brood XIX but localized genetically due to geographic isolation.
Behavioral Traits: Less studied than Brood XIX but displays similar mass emergence behavior.

Brood XXIII

Geographic Range: Primarily located in parts of Missouri and Illinois.
Emergence Years: Emerged most recently in 2015; next expected in 2028.
Identification Features: Comparable physical appearance but with distinct local adaptations.

How to Identify Different Broods: Key Strategies

1. Identify by Year of Emergence

The simplest way to identify a particular brood is by knowing which year it is expected to emerge. Since each brood follows a strict 13-year cycle:

Check regional records or scientific databases that track periodical cicada emergences.
Use the last known emergence year as a baseline and add multiples of thirteen.

For example:

| Brood | Last Emergence | Next Expected Emergence |
|———–|—————-|————————|
| Brood XIX | 2011 | 2024 |
| Brood XXII| 2009 | 2022 |
| Brood XXIII| 2015 | 2028 |

If you observe periodical cicadas emerging en masse during one of these years in their known geographic areas, you can reasonably deduce which brood they belong to.

2. Geographic Location Mapping

Mapping is essential for confirming brood identity:

Use detailed maps provided by entomological societies such as The Cicada Mania Project or university extensions.

Compare your observation location against known brood distributions.

If you live in or visit an area known for a specific brood’s emergence during its expected year (e.g., southeastern U.S. during a Brood XIX emergence), you can identify the brood accordingly.

3. Morphological Examination

While all Magicicada species share similar features — black bodies with bright red eyes — subtle differences exist among species within each brood:

Magicicada tredecim tends to have more orange coloration on the abdomen.

Magicicada neotredecim males can be distinguished by their unique calling songs (acoustic differences).

Using magnification tools or consulting taxonomic keys can help differentiate between species within broods if multiple are present.

4. Acoustic Analysis

Male periodical cicadas produce loud mating calls that differ between species:

Each species within a brood has a distinctive song frequency and rhythm.
Audio recording devices combined with software analysis can help identify which species — and thus which brood — are present.

For instance, researchers use spectrograms to analyze call frequencies ranging from about 1 kHz to several kHz.

5. Genetic Testing

For precise scientific identification, genetic sampling can distinguish between broods:

DNA barcoding can confirm species identity down to population-specific lineage.
This approach requires laboratory facilities but provides reliable results especially when broods overlap spatially.

Practical Tips for Cicada Enthusiasts

If you want to identify different broods of 13-year periodical cicadas yourself:

Timing Your Observations

Periodical cicadas only emerge for about four to six weeks during late spring to early summer (usually May through June). Plan your observations accordingly during predicted emergence years.

Document Location Carefully

Record GPS coordinates when observing cicadas so you can cross-reference your data with known brood maps.

Use Photography and Audio Recording

Capture high-resolution photographs showing key physical features like eye color and wing venation. Record male calls for acoustic analysis.

Connect with Citizen Science Projects

Participate in programs like Cicada Safari or local university projects that track periodical cicada emergences—your observations may contribute valuable data.

Learn About Local Tree Species

Periodical cicada nymphs feed on roots of certain hardwood trees such as oak, hickory, and maple. Understanding local flora can help anticipate emergence sites.

Conservation Considerations

Though periodical cicadas are generally abundant during emergences, habitat loss and climate change may affect future populations. Proper identification helps conservationists monitor population health over time.

Avoid disturbing natural habitats when observing these insects—periodical mass emergences are vital ecological events supporting many predators like birds and small mammals.

Conclusion

Identifying different broods of 13-year periodical cicadas involves understanding their unique life cycles, mapping their geographic ranges, noting emergence years, examining physical characteristics, analyzing acoustic signals, and sometimes conducting genetic testing. By combining these methods with careful observation during predicted emergence periods, both scientists and enthusiasts can accurately identify which brood they are witnessing.

This knowledge illuminates the complex biology of these mesmerizing insects while promoting awareness and appreciation for one of nature’s most extraordinary periodic phenomena. Whether you are a seasoned entomologist or a curious observer—knowing how to distinguish these broods enriches your experience with the remarkable world of periodical cicadas.