Brood XIII

Ravinia

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.

2020 Sub-Brood

Some of the Northern Illinois Sub-Brood (part of Marlatt's XIII) cicadas emerge 4 years early, as they did in the Chicago area during 2020.

2024 emergence

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, were expected to emerge together in 2024 for the first time since 1803. However, the two broods were 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 would likely have been the same as usual.Multiple sources:

• The next such dual emergence is expected to occur in 2245, 221 years after 2024.Multiple sources:

Pests and parasites

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.Multiple sources:

• First report of Pyemotes herfsi parasitism on periodical cicada eggs.
• Contains 1:38 minute video showing images and descriptions of Pyemotes herfsi bites.

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.

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. Similar events occurred in Cincinnati after a Brood XIV emergence ended in 2008,Multiple sources:

in Cleveland and elsewhere in northern and eastern Ohio after a Brood V emergence ended in 2016,Multiple sources:

• in the Washington, D.C., area after a Brood X emergence ended in 2021,Multiple sources
• Contains a 1:38 minute video showing images and descriptions of Pyemotes herfsi bites.
• and again in the Chicago area after the next Brood XIII emergence ended in 2024.Multiple sources:

Gallery

File:Cicadas climbing.jpg|Brood XIII Magicicada in various stages of molting. File:Premolt Brood XIII.JPG|Brood XIII instar File:Newly molted Brood XIII.JPG|Newly molted Brood XIII File:Cicada bush0001.JPG|A group of Brood XIII Magicicada on a bush File:Cicada BroodXIII 1200x800.jpg|Brood XIII in Westchester, Illinois, on June 21, 2007 File:BroodXIIIBrookfield.jpg|Brood XIII Magicicada at Brookfield Zoo in May 2024 File:Brood XIII 2024 - Itasca.jpg|Brood XIII at Springbrook Nature Center, Itasca in June 2024

References

References

1. Susan L. Post. "A Trill of a Lifetime". University of Illinois.
2. David Marshall, John Cooley, Chris Simon. (2024). "Magicicada broods and distributions". University of Connecticut.
3. "Timed to perfection: Cicada's biological clock determines emergence". [[University of Illinois College of Agriculture, Consumer, and Environmental Sciences.
4. (12 July 2020). "Chicago Area Periodical Cicada Emergences in 2020".
5. "Genus ''Magicidada'': periodical cicadas". [[University of Florida]].
6. (2007-03-14). "Cicadas' Return Worries Festival Organizer". [[NPR]].