Any day now, two of the seven named periodical cicada broods will emerge from the ground, molt, and take to the trees serenading. There may be trillions of cicadas in 17 states across the Southeast and Midwest. The birds will have quite a feast.
Most times when the 13- and 17-year cicadas co-emerge, every 5 or 6 years, the two broods have some distance between them, according to the University of Connecticut’s site dedicated to periodical cicadas. But these two broods are geographically adjacent, which happens about once a quarter-century.
The last time these two specific broods (XIX – 13 year and XIII 17-year) emerged together was in 1803. Thomas Jefferson was president, Ralph Waldo Emerson was born, and the U.S. had just acquired Louisiana.
Illinois is the only state where broods XIX and XIII might emerge simultaneously or overlap. Some areas of Indiana and Iowa will see either Brood XIX or Brood XIII, but there will be no overlap of broods in either state.
Cicadas typically appear in early to mid-April or May in the south and a bit later (May or June) in the colder parts of the country. The timing all comes down to soil temperature. Cicada nymphs begin to emerge when the temperature about 7 to 8 inches below the Earth’s surface warms up to around 64°F (about 18°C). It takes a few days for newly emerged nymphs to molt and reach full maturity so that the pre-mating song can begin as it has in some places already.
In Maryland, the 13-year Brood XIX Cicadas will begin emerging in southern St. Mary’s County this Spring.
If you see cicadas in your neighborhood, you can document your observations on the free apps iNaturalist and Cicada Safari. If you do record your observations on these apps, include the number of cicadas in the area, whether you see one or two cicadas—or the trees around you are covered in them. Happy Hunting.