Brood XXII (also known as The Baton Rouge 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 ...

, last seen in 2014 in a geographic region centered on

Baton Rouge, Louisiana Baton Rouge ( ; ) is a city in and the capital of the U.S. state of Louisiana. Located the eastern bank of the Mississippi River, it is the parish seat of East Baton Rouge Parish, Louisiana's most populous parish—the equivalent of counties i ...

, as well as other locations in southeast

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 ...

and southwest

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 ...

. Periodical cicadas (''Magicicada spp.'') are often referred to as "17-year locusts" because most of the known distinct broods have a 17-year life cycle. Brood XXII is one of only three surviving broods with a 13-year cycle. The next emergence of The Baton Rouge Brood is expected in 2027.

Position among other broods of cicadas

Every 13 years, Brood XXII tunnels ''en masse'' to the surface of the ground, mates, lays

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s, and then dies off in several weeks. In 1907, the entomologist C. L. Marlatt postulated the existence of 30 different broods of periodical cicadas: 17 distinct broods with a 17-year life cycle, to which he assigned Roman numerals I through XVII (with emerging years 1893 through 1909); plus 13 broods with a 13-year cycle, to which he assigned Roman numerals XVIII through XXX (1893 through 1905). Many of these hypothetical broods, however, have not been observed. Today, only 15 are recognized. Brood XXII is one of three extant broods of 13-year cicadas. The other two are Broods XIX and XXIII, expected to re-emerge in 2024 and 2028 respectively. A fourth 13-year brood, Brood XXI (The Floridian Brood) was last recorded 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. ...

, but is believed to be now extinct.

Species present

Brood XXII includes three of the four different species of 13-year cicadas: '' Magicicada tredecim'' (Walsh and Riley, 1868), '' Magicicada tredecassini'' (Alexander and Moore, 1962), and '' Magicicada tredecula'' (Alexander and Moore, 1962).

References

External links

Magicicada.org: Brood XXII
{{DEFAULTSORT:Brood 22 Cicadas