Map of periodic cicada broods with Brood XIII shown in brownBrood XIII MagicicadaBrood XIII Magicicada molting from its old exoskeleton
Brood XIII (also known as Brood 13orNorthern Illinois Brood) is one of 15 separate broods of periodical cicadas that appear regularly throughout the midwestern United States. Every 17 years, Brood XIII tunnels en masse to the surface of the ground, mates, lays eggs in tree twigs, and then dies off over several weeks.
Entomologist Charles Lester Marlatt published an account in 1907 in which he postulated the existence of 30 broods. The number has since been consolidated, and only 15 broods of periodical cicadas are currently recognized. Of these, twelve (Broods I through X, XIII, and XIV) are 17-year broods and three (Broods XIX, XXII, and XXIII) are 13-year broods.[1] Brood XI is extinct and Brood XII is not currently recognized as a brood of 17-year cicadas.[2]
The 4 cm (1.6 in) long black bugs do not sting or bite. Once they emerge, they spend their two-week lives climbing trees, shedding their exoskeletons and reproducing. Brood XIII can number up to 1.5 million per acre (3.7 million per hectare). The brood is reputed to be the largest emergence of cicadas known anywhere.[3]
The brood's most recent major emergence occurred during the spring and early summer of 2024, throughout an area roughly enclosed by northern Illinois, eastern Iowa, southern Wisconsin, and a narrow strip of Indiana bordering Lake Michigan and Michigan.[3] A premature emergence occurred in 2020.[4] The brood will emerge again in late May 2041.[2][3][5]
In the northern Chicago suburb of Highland Park, there was a concern about whether the cicadas's sounds might drown out the music at the Ravinia Festival during May and June, the peak months of cicada activity in 2007. According to the Chicago Tribune, Ravinia adjusted the schedule so that Chicago Symphony Orchestra (CSO) concerts took place in July, after the emergence had ended. Apart from the CSO concerts, all other events took place as scheduled.[6]
After the 2007 Brood XIII emergence had ended, many people in Chicago's suburbs reported in early August the development of rashes, pustules, intense itching and other skin conditions on their upper torso, head, neck and arms. Rashes and itching peaked after several days, but lasted as long as two weeks. Anti-itch treatments, including calamine lotion and topical steroid creams, did not relieve the itching.[7]
Edmond Zaborski, a research scientist with the Illinois Natural History Survey, then discovered that the skin conditions had resulted from oak leaf gall mite ("itch mite") (Pyemotes herfsi) bites. Zaborski further found that the mites were ectoparasites whose numbers had increased while feeding on the brood's eggs.[7]
The mites usually feed on oak leaf gall midge (Polystepha pilulae) larvae and other insects, but, as Zaborski found, also parasitize periodical cicada eggs when those are available. In 2021, many people in the Washington, D.C. area experienced similar skin conditions after an emergence of Brood X had ended.[7]
Brood XIII of the 17-year cicada, which reputably has the largest emergence of cicadas by size known anywhere, and Brood XIX of the 13-year cicada, arguably the largest (by geographic extent) of all periodical cicada broods, are expected to emerge together in 2024 for the first time since 1803. However, the two broods are not expected to overlap except potentially in a thin area in central and eastern Illinois (Macon, Sangamon, Livingston, and Logan counties). Therefore, the density of cicadas in most areas will likely be the same as usual.[8] The next such dual emergence is expected to occur in 2245, 221 years after 2024.[9]
^Susan L. Post. "A Trill of a Lifetime". Illinois Natural History Survey. Champaign, IL: University of Illinois. Archived from the original on 2012-05-11. Retrieved 2024-01-25.
^ abDavid Marshall, John Cooley, Chris Simon (2024). "Magicicada broods and distributions". Ecology and Evolutionary Biology. Cicadas. Storrs, Connecticut: University of Connecticut. Retrieved 2024-01-25.{{cite web}}: CS1 maint: multiple names: authors list (link)
^ abcSchuster, James; Nixon, Philip. "Timed to perfection: Cicada's biological clock determines emergence". Insects: Cicadas. Urbana, Illinois: University of Illinois Urbana-Champaign College of Agricultural, Consumer and Environmental Sciences: Illinois Extension. Archived from the original on March 10, 2024. Retrieved March 12, 2024. The northern Illinois brood, which will emerge in late May 2024, has a reputation for the largest emergence of cicadas known anywhere. This is due to the size of the emergence and the research and subsequent reporting over the years by entomologists Monte Lloyd and Henry Dybas at the Field Museum in Chicago. During the 1956 emergence, they counted an average of 311 nymphal emergence holes per square yard of ground in a forested floodplain near Chicago. This translates to 1½ million cicadas per acre. In upland sites, they recorded 27 emergence holes per square yard, translating to about 133,000 per acre. This number is more typical of emergence numbers but is still a tremendous number of insects. .... 2020 | Northern Illinois Sub-Brood (part of Marlatt's XIII)
Broce, Alberto B.; Kalisch, James (October 2007). "Oak leaf itch mite"(PDF). Pests That Affect Human Health. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF-2806. Archived from the original(PDF) on July 16, 2011.
"2024 Cicada Forecast". Cicada Mania. February 10, 2024. Archived from the original on March 8, 2024. Retrieved March 13, 2024. Both Brood XIX and XIII exist in Macon, Sangamon, Livingston and Logan counties in Illinois. The easily accessible place they come closest to overlapping is Springfield, Illinois, which is in Sangamon County.
Schuster, James; Nixon, Philip. "Timed to perfection: Cicada's biological clock determines emergence". Insects: Cicadas. Urbana, Illinois: University of Illinois Urbana-Champaign College of Agricultural, Consumer and Environmental Sciences: Illinois Extension. Archived from the original on March 10, 2024. Retrieved March 12, 2024. The northern Illinois brood, which will emerge in late May 2024, has a reputation for the largest emergence of cicadas known anywhere. This is due to the size of the emergence and the research and subsequent reporting over the years by entomologists Monte Lloyd and Henry Dybas at the Field Museum in Chicago. During the 1956 emergence, they counted an average of 311 nymphal emergence holes per square yard of ground in a forested floodplain near Chicago. This translates to 1½ million cicadas per acre. In upland sites, they recorded 27 emergence holes per square yard, translating to about 133,000 per acre. This number is more typical of emergence numbers but is still a tremendous number of insects.
"The 2024 Periodical Cicada Emergence". Biodiversity Research Collections: Periodical Cicada Information Pages. Storrs, Connecticut: University of Connecticut. Archived from the original on March 12, 2024. Retrieved March 13, 2024. In 2024, 13-year Brood XIX, which is the largest of all periodical cicada broods, will co-emerge with 17-year Brood XIII; these two broods are adjacent (but not significantly overlapping) in north-central Illinois.
"Brood XIX: The Great Southern Brood". Biodiversity Research Collections: Periodical Cicada Information Pages. Storrs, Connecticut: University of Connecticut. Archived from the original on February 24, 2024. Retrieved March 13, 2024. Brood XIX is arguably the largest (by geographic extent) of all periodical cicada broods, with records along the east coast from Maryland to Georgia and in the Midwest from Iowa to Oklahoma.
Ortiz, Aimee (January 19, 2024). "The World Hasn't Seen Cicadas Like This Since 1803". The New York Times. Archived from the original on March 9, 2024. Retrieved March 13, 2024. Brood XIX and Brood XIII will both emerge this spring. The last time these bugs showed up at the same time in the United States, Thomas Jefferson was president. After this spring, it'll be another 221 years before the broods, which are geographically adjacent, appear together again.
