LUNCH IN THE LAB -- June 18, 2013 at 11:13 AM ET
How to Woo a Cicada
A periodical cicada basks in the sun at a cemetery in Lorton, Virginia. Photo by Jenny Marder.
On a hot spring day in late May, I went hunting for periodical cicadas with John Cooley, a veteran expert of the behavior, distribution and unusual courtship rituals of these insects. The trip was for a tape piece we've been preparing on cicadas, which is slated to air on Wednesday's NewsHour broadcast.
As our van pulled into Deep Run Park, just outside Richmond, Va., a noise rose up from the din, first a soft buzzing, like a bike engine from a distance, but rising increasingly in volume and pitch as we drove along a row of tall pine trees lining the road.
"This is a fairly pure chorus of Magicicada septendecim," Cooley said, referring to the specific species of periodical cicada. "I can see one flying right over there."
Sure enough, a cicada was flitting along the treetops. And then another. And another. Cicadas in cicada territory are like stars. The longer your eyes search for them, the more the bugs come into focus, and the more you see.
The cicadas that emerged this spring from Georgia to Connecticut belong to a 17-year brood, known as Brood II.
The car pulled to a stop in the parking lot, and Cooley climbed out, strode over to the trees and plucked two male cicadas from their branches.
"Now you're mine," he told them, not unkindly.
And they were his. Cooley, we learned, is a cicada whisperer. Nearly 20 years ago, the University of Connecticut researcher and his partner had made a discovery. It's long been known that the males are the singers of the species -- they're the ones creating the 100-decibel racket, "the big boy band in the trees," Michael Raupp, an entomologist from the University of Maryland has called it.
The males bellow out for weeks to attract a mate, producing a frenzied, raucous cacophony of wooing. Not unlike what you see on an episode of "The Bachelorette." Or any movie that features multiple men competing to bed Cameron Diaz.
But what Cooley and Dave Marshall had discovered was that females signal too, with a soft click of their wings.
In the case of this species, the male song is comprised of a long tone followed by a quick downstroke, which Cooley can whistle so precisely, it's hard to tell if the sound is coming from him or from the red-eyed, black-bodied, veiny winged creatures, now crawling across his tee shirt and onto the microphone receiver we've attached to the waistband of his trousers.
Biologist and researcher John Cooley uses a junk light switch to attract and capture the attention of a male cicada. From video by Charlie Voth.
Then the female, if she likes the look of him, will click her wings in approval. And only then will the male be encouraged to pursue her.
"When a female makes that little click signal, that's a sound of mating acceptance," Cooley said. "So you get these duets with all this courtship involved and eventually that culminates in a mating."
As the bugs crawled across his chest, arms and wrist, he demonstrated the noise by clicking his thumb and pointer fingernails together, until that proved unsatisfactory, at which point he stuck the bugs in his mouth to free up his hands. Their little legs hung out from his pursed lips, waving frantically, as he pulled his bag from the car trunk and rifled through his laundry, finally producing from the bottom what he was searching for: an old light switch "from the junk box."
He placed the bugs back on his wrist and clicked the light switch again and again, mimicking, he explained, a female. The male cicadas crawled toward the sound, fixated.
in 2001, Cooley and David Marshall published a paper showing that male cicadas produce not just one sound, but several. As the female begins the wing click, their call changes, becoming faster and more constant. And then it changes again just before the act of mating occurs.
From Cooley's Magicicada.org website:
"Under some circumstances, males engaged in duets acoustically obscure the downslurs of potential competitors, reducing the likelihood of a female response and increasing the likelihood that competing males will continue chorusing, depart and search elsewhere."
It is a complicated and sophisticated duet that is unique to this insect and that varies slightly according to the cicada species. And its hold on the male is remarkably strong.
"You see, he's my friend for life now," Cooley said of the cicada still moving across his wrist. "He'll stick around forever. There's very little I can do to him that will make him go away at this stage."
He waved his hand up and down and indeed, the cicada clung to it, going nowhere.
"Look at that," he said. "It's not flying away... All the normal things that an insect would do, like try to get away and all that, all that's gone by the wayside here, because it is as if there is a receptive female somewhere around here."
He shook his head. "There isn't. All we have is this," he points to the light switch. "It's just because we've learned to crack the code that these insects use."
Miles O'Brien had this report for Science Nation last week on the sensory systems of boas, pythons and pit vipers.
Space.com has a look at NASA's eight new astronaut recruits.
And The New York Times has this profile of Bill Nye the Science Guy - who's taking on more than just teaching science to children these days.
NOT SAFE FOR LUNCH
"The last thing most people would want in their bodies is mucus laden with viruses," Science News reports. "But a new study suggests that viruses called bacteriophages, or phages, grab onto mucus and then infect and kill invasive bacteria."