For cicadas and a researcher who studies them, it's all about sex

A cicada sits on a twig in a forest preserve June 11, 2007 in Willow Springs, Illinois. The cicada is one of millions in the area that emerged from the ground and took to the trees, part of a 17-year hatch cycle.
Scott Olson/Getty Images

It's one thing to find insect sex interesting. But to find sex among insects more interesting than sex among humans, as Marlene Zuk does, is something else altogether.

A Minnesota-based biologist, Zuk is traveling to New York City this week to participate in an event called "Cicada Serenades: Music, Mating and Meaning" at the World Science Festival. She joins Kerri Miller to discuss cicadas and other topics from the insect world.

Since 1996, a vast number of cicadas have been biding their time, feeding on tree roots and waiting 17 years to reemerge. Their arrival is part of the process that Zuk finds so much more interesting among bugs than among people.

People "always think I'm not going to be able to defend that, and I think I pretty much always have," she tells Kerri. "I have never lost. ...

"We can start even from the very beginning. Insect sperm is more interesting than human sperm. We all think there's a standard; it looks like a little tadpole, it swims around, it swims to the egg and then we're done. Well, not in insects. A lot of insects will have sperm that has very peculiar shapes, or they'll have multiple forms of sperm. And there's a kind of fruit fly that has sperm longer than its own body."

Zuk's studies center on crickets, though she can speak knowledgeably about cicadas and other species. At the moment, the public is interested in cicadas because of the brood emerging on the East Coast. They're hard to ignore because they make a racket — a loud, unremitting drone that can drown out other sounds, like human speech.

"Otherwise, we'd never pay any attention to them at all," Zuk said.

Why do they make that noise? Again, Zuk says the answer is: Sex. "Pretty much, noise in insects is all about sex," she said. "You can take that as a given," except for insects that make noise incidentally, as in flight. The rest are making noise to attract a mate.

"It's incredibly loud. People are saying that when the emergence comes out in the East, as it has just started now, depending on how close you're standing, it's like a jet engine taking off. It's really loud. And so they do this, and they're sitting on a branch, and at some point a female will fly over to the male that's making that sound, and she'll sit there, head to head with him, and he'll continue to make that sound. And sometimes they'll mate after an hour, and sometimes she'll just fly away after an hour. And sometimes nothing will happen for hours and hours. ...

"It is connected with finding a mate, but the steps don't seem as orchestrated [as in other species]. But that's from the perspective of a cricket person."


Cicada Serenades: Music, Mating, and Meaning
"After 17 years underground, cicadas throughout the Northeast are emerging in time for the 2013 World Science Festival to sing, mate and die. Amid a buzzing, whirring chorus, we examine the extraordinary mating rituals of these and other six-legged creatures to find out what their songs are saying, why they're saying it, and how this knowledge is impacting our understanding of communication, behavior, and the ecosystem." (World Science Festival)

17 Years to Hatch an Invasion
Now, at last, they are ready to produce the next generation. The adult males are snapping rigid plates on their abdomens to produce their courtship song. The females are clicking their wings to signal approval. They will mate and then die shortly afterward. Their time in the sun is short, but their 17-year life span makes them the longest-lived insects known. (The New York Times)

The Song of the Cicada
Once their breeding and egg-laying is done, the cicadas have nothing left to do but die, which they do more or less en masse. People who have lived through an emergence vividly remember the distinctive crunching sound a dead cicada makes when you inadvertently step on it." (The New Yorker)

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