By One of the most peculiar of North America’s natural wonders — the synchronized mass mating frenzies of big, obsessed insects called periodical cicadas — is playing out across the southeastern and midwestern United States.
The year 2024 offers a particularly good display. The biggest, in geographic extent, of all the in-sync groups (called broods) is emerging from soil into daylight this spring. Known as Brood XIX, it spans roughly from Georgia into Illinois. And unlike 2021’s extravaganza (SN: 12/14/21), this time a second multispecies brood in the Midwest (called Brood XIII) means all seven of North America’s named species will be showing off somewhere.
Love ‘em or hate ‘em, periodical cicadas offer nature watching at its friendliest. No binoculars needed. Neither young cicadas nor adults have body parts that can sting or bite. Plus, these cicadas are so easy to catch for a close-up — just reach out and pick one up.
Here are answers to some cicada-watcher questions.
What is a cicada?
The seven cicada species causing the fuss in North America this spring live a rare lifestyle but still belong among the 3,000-plus members of the Cicadidae family. The special seven get called locusts — but they’re not.
Among their cicada family traits are glassy wings and piercing soda-straw mouths. The bugs drive the tiny straws into a plant’s water-plumbing system. There’s a lot more water than nutrition to deal with, and several kinds of cicadas have surprised researchers by peeing in skinny little jets instead of drop-by-drop, which was supposedly the disposal method for such small animals.
Out of these several thousand cicada species, only nine so far are known to live in lockstep groups in what’s called a periodical life style. Seven of these, in North America, have earned the genus name Magicicada. And their apparent vanishings are nature’s now-you-see-it/now-you-don’t magic trick.
Why do cicadas disappear?
Periodical cicadas live a rare lifestyle of super-synchrony. They survive for 13 or 17 years, and all the periodical species in a particular swath of landscape go through their phases of life together.
Imagine visiting Chicago and seeing no one. The city’s entire population has in unison hidden underground. And there are no grown-ups in the city or any variety in age, just a single age-class of insect toddler-equivalents or tweens or teens. To a human, the scene could have an eerie-movie vibe: One kindergarten class has escaped Armageddon.
Young and hungry, they burrow here and there in soil, sucking nutrients out of plant roots for 17 years. (Yes, they really do live that long, which is extraordinary for an insect.) After a life of sucking underground plant juices, everyone develops an interest in sex for the first time. The youngsters dig upward into sunlight and metamorphose into a body form with adult parts. Suddenly it’s a crazy, crowded place with young adults loudly flirting and making the most of the mere 1 percent of their lifetime allotted for copulation.
This is dense and diverse city living, by the way. Even the aboveground mating frenzy can contain a mix of three species, all on the same schedule. In the end, they sort out mating with the right species. Even to human ears, various male seduction sounds differ, especially the kind with the old-movie spaceship whine.
That’s what’s happening — bug-wise — in Chicago right now.
Then they go back underground?
Sort of. After several loud and lively weeks, Chicago has millions of cicada eggs hidden in gashes in tree twigs, cut by mothers wielding a tough, sharp, egg-delivery structure.
Then all the parents drop dead.
Within a few months, the next generation hatches into this citywide cicada deathscape, plummets from the cozy tree bark hatching spots and digs itself underground. For another 17 years, the offspring will pirate watery nutrition from plant roots. Chicago aboveground again looks empty of all its big, loud Magicicada — until that seventeenth springtime.
How do they count?
Good question. Some researchers think the insects pick up seasonal clues from the plant roots they suck on. Three species have 17-year cycles, and four species live in 13-year boom-and-busts. Cicadas don’t always count right, though. Emerging early or late, however, means a much greater risk of getting eaten by birds or other predators.
Why the odd numbers?
For years, some scientists wrote papers about possible advantages of odd numbers, such as becoming harder for predators to predict. Though the discussion gets especially complicated when considering that two periodical cicada species, living outside the United States, have even-numbered cycles.
The four-year cycling one (Chremistica ribhoi), in India, is nicknamed the World Cup cicada because the phenomena coincide. In Fiji, a mustard-colored cicada species (Raiateana knowlesi) mates on an eight-year cycle and has been featured on a Fijian $100 bill.
Why are cicadas so loud?
Ah yes, the earworm of cicada season: that incessant buzzing.
In daytime and dusk, that’s probably the sound of male cicadas. Plenty of nonperiodical cicadas create a summertime buzz too, and periodical or not, they use some version of cicada macho-abs. An abdominal segment has ridged plates called timbals that make a racket when a big muscle inside the abdomen repeatedly flexes, making the timbals shift and then pop back into shape.
The din might be twice as loud if females too made noise as part of courtship. But they respond with a wing flick gesture if interested in a particular male. The idea that Magicicada females participate actively went unnoticed for several decades. In 2001, entomologists John Cooley, now at the University of Connecticut in Storrs and David Marshall, at the University of Michigan in Ann Arbor, described how important female wing flicks are in responding to male ab-snaps. Even an electric light switch, when clicked seductively, can inspire a male to try mating with it.
What’s the “flying saltshaker of death” stuff in some cicada headlines and tweets?
It’s the catchy descriptor for a cicada with a particular kind of fungal sexually transmitted disease.
An eager adult Magicicada digging up to the surface to mate can pick up spores of Massospora. Eventually the infected cicada’s rear will break off, revealing a pale plug of fungus that has flourished inside it. The plug “crumbles easily when pressed between your fingers,” says Matt Kasson of the University of West Virginia in Morgantown. Yet having a butt fall off doesn’t stop the mating frenzy, and Kasson and his colleagues have figured out how the STD manages.
The fungus doses its Magicicada victim with an amphetamine called cathinone, the researchers have found. The stuff may sound familiar as the chemistry that powers the long traditions of chewing qat plants in the Middle East and parts of Africa. In Magicicada, an infected male cicada will wing flick like females, attracting other males that don’t notice or don’t care that the partner is only half there at best.
