Brood XXIII (also known as the Mississippi Valley Brood) is a brood of 13-year

periodical cicadas The term periodical cicada is commonly used to refer to any of the seven species of the genus ''Magicicada'' of eastern North America, the 13- and 17-year cicadas. They are called periodical because nearly all individuals in a local population ...

that last emerged in 2015 around the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

in the states of

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...

, and

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

. The brood was also seen in Southwestern Indiana and Western Kentucky around the

Ohio River The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...

, and as far north as

Weldon Springs State Park Weldon Springs State Park is a state park located near Clinton, Illinois. It centers on Salt Creek and the impoundment of a tributary, Weldon Springs, to form Weldon Spring Lake, a reservoir. It is supervised by the Illinois Department of Nat ...

DeWitt County, Illinois DeWitt County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 16,561. Its county seat is Clinton. The county was formed on March 1, 1839, from Macon and McLean counties. The county was named in ho ...

. Brood XXIII is one of three extant periodical cicada broods with a 13-year life cycle, and thus is expected to be seen again in 2028.

Lifecycle and history

Every 13 years Brood XXIII cicadas tunnel ''en masse'' to the surface of the ground in late-April to early-June of emergence years to molt,

mate Mate may refer to: Science * Mate, one of a pair of animals involved in: ** Mate choice, intersexual selection ** Mating * Multi-antimicrobial extrusion protein, or MATE, an efflux transporter family of proteins Person or title * Friendship ...

, lay eggs, and subsequently die off over the course of a few weeks. After the eggs hatch, the nymphs burrow back underground to further develop and grow for the next 13 years before emerging again, completing the cycle. The extreme number of emerging cicadas is often given as an example of

predator satiation Predator satiation (less commonly called predator saturation) is an anti-predator adaptation in which prey briefly occur at high population densities, reducing the probability of an individual organism being eaten. When predators are flooded with ...

. Brood XXIII was first specifically described in 1845 by Dr. D.L. Pharas of

Woodville, Mississippi Woodville is a town in and the county seat of Wilkinson County, Mississippi, United States. Its population as of 2020 was 928. History This historic town, one of the oldest in Mississippi, is set among the rolling hills and pastures of Wilkins ...

in a local newspaper, the ''

Woodville Republican The ''Woodville Republican'' is a weekly newspaper published in Woodville, Wilkinson County, Mississippi. It is the oldest newspaper, as well as the oldest business, in continuous incorporated operation in Mississippi Mississippi () is ...

''. Brood XXIII is only one of three still living 13-year cicada broods; the other two are

Brood XIX Brood XIX (also known as The Great Southern Brood) is the largest (most widely distributed) brood of 13-year periodical cicadas, last seen in 2011 across a wide stretch of the southeastern United States. Periodical cicadas (''Magicicada spp.'') ...

(the "Great Southern Brood") and

Brood XXII Brood XXII (also known as The Baton Rouge Brood) is a brood of 13-year periodical cicadas, last seen in 2014 in a geographic region centered on Baton Rouge, Louisiana, as well as other locations in southeast Louisiana and southwest Mississippi. Pe ...

(the "Baton Rouge Brood"). Brood XXI (the "Floridian Brood") was a fourth 13-year brood that was last seen in 1870 in the

Florida Panhandle The Florida Panhandle (also West Florida and Northwest Florida) is the northwestern part of the U.S. state of Florida; it is a Salient (geography), salient roughly long and wide, lying between Alabama on the north and the west, Georgia (U. ...

and along the Alabama–Mississippi border. It is presumed

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

Species present

Brood XXIII includes all four 13-year cicada species: *'' Magicicada tredecim'' (Walsh & Riley, 1868) *'' Magicicada neotredecim'' (Marshall & Cooley, 2000) *'' Magicicada tredecula'' (Alexander & Moore, 1962) *'' Magicicada tredecassini'' (Alexander & Moore, 1962)

References

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