By Michael Stroh
May 26, 2004
Oh, they're loud, you say.
Well, don't bother telling Marian Farabee, who probably can't hear you anyway. Her backyard cicadas are so intense, she jams earplugs into her ears before venturing outside to garden.
"It's like Harleys," says the Columbia resident. "A few start up, then all of a sudden, they all start up and kind of roar."
Or Kevin Dietz, who unsuccessfully tried to drown out the sound of the little devils in his Rodgers Forge apartment by cranking up his television.
"It's the only thing you can hear. It sounds like I'm living in the Amazon," says Dietz.
Yes, ears are ringing all over Baltimore as male 17-year cicadas from Brood X break their silence -- and, incidentally, a few public noise regulations -- in an earsplitting effort to land a mate.
These high-decibel pleas pack enough sonic punch to overpower lawn mowers, truck traffic and the crackle of walkie-talkies. They're forcing some softball players to holler for pop flies and homeowners to miss phone calls.
One of the long-standing scientific mysteries surrounding cicadas is how a shrimp-sized insect manages to belt out such songs. It has only been in the past decade that a small group of biologists has begun to piece together the puzzle.
Cicada songs begin inside a pair of drumlike organs -- tymbals -- on either side of the male insect's abdomen. When the cicada wants to sing, it tenses a muscle attached to each tymbal, distorting the structure much the way a soda can dents when poked with a finger.
This buckling produces a pulse of sound, which travels into an large air sac in the insect's abdomen. The pressure generated by the tymbal pulse is powerful: "roughly equivalent to that generated by a grenade exploding one meter away," writes zoologist Henry Bennet-Clark of Oxford University in a 1998 Scientific American article.
But the real secret to the cicada's sonic punch, Bennet-Clark and others have found, stems from an unusual source: the insect's ears.
A pair of thin eardrums on the abdomen are designed not only for hearing but for amplifying sound waves reverberating in the insect's air sac. When cicada song leaves the eardrums, it's roughly 20 times louder than the clicks produced by the tymbals, scientists have found.
Driving through a leafy Bowie neighborhood with a Quest Technologies Model 2900 hand-held decibel meter, they piled out in front of a ranch-style house on Stonehaven Lane. Two big white ash trees stood in the front yard, alive with cicadas.
The insects, which clung to many of the leaves, were so loud they were audible even with the car windows rolled up. Williams checked her earplugs as she climbed from the car. Otherwise, she says, "it's painful after three or four minutes."
Brood X is composed of three species of cicada, each with a distinctive call, explains Williams.
Magicicada septendecim, the biggest and most common of the three, sounds like a giant Weed-whacker or sci-fi spaceship. Magicicada cassini produces a "tick, tick, tick ... zzzzzt" sound in quieter moments. When it's not -- the norm -- it makes a harsh screeching noise like the sound of a "million baby rattles," says Williams. "They're the loudest."
The third species, Magicicada septendecula, also produces a ticking noise but is the rarest of the three and much harder to distinguish, Williams says.
The ash trees were filled with Magicicada septendecim and Magicicada cassini, Williams said. Pagac held the decibel meter in the air. Its digital readout quickly started to climb.
87.2 ... 89.4 ... 89.9
"How high can we go?" hollered Williams, wearing a tie-dye yellow T-shirt with the image of Magicicada septendecim on the front.
The meter topped out at 90.3 decibels-- slightly louder than a lawnmower. Last weekend, Williams said, she found a tree that measured 92 decibels.
Not everybody is finding the high-decibel dirges so cool, however.
At the Baltimore Zoo, employees have been forced to shout in the thickly wooded areas and listen hard for the sound of their walkie-talkies.
"Do you realize maintenance is trying to get you on the radio?" a panting keeper told zoo employee Ben Gross yesterday after catching up to him on the the cicada-infested African boardwalk.
In Lauraville, musician Gavin Elder can hear the bugs between songs in the basement recording studio at his home even with the window shut. He has been thinking about giving them a part on his coming psychedelic surf album.
"They have a really great other-worldly drone," he said. The liner notes, he imagines, could read "backing vocals by Brood X."
Elder's wife, Traci, said the cicadas are so loud they drown out the phone, causing them to miss three calls last weekend.
But the couple said that in some ways they'll miss the creatures when they're dead in a few weeks -- their songs mask the more annoying sound of traffic on nearby Harford Road.
The cicadas should consider themselves lucky they're bugs.
In some areas, the Maryland Occupational Safety and Health Administration could cite them for exceeding the 85- to 90-decibel limit set by law, according to spokeswoman Linda Sherman.
Regulators at the city Health Department's environmental health section would crack down, too. Daytime noise limits are set at 58 decibels at the property line in residential areas. Power tools and air-conditioning equipment are not allowed to exceed 70 decibels during the daytime in the city's neighborhoods.
None of the agencies said they planned any enforcement action, however.
Sun staff writers Julie Bell, Jonathan Bor and Frank D. Roylance contributed to this article.
Copyright © 2013, The Baltimore Sun