Eine Kleine Nacht Musik
Lean from your window and listen on a warm July night when the Milky Way clabbers the sky with light and the air smells like freshly-ironed sheets. You'll hear summer: Crickets chiming from the grass, katydids sawing the darkness with raspy wings. But what if the singing stopped? Would you miss it? Field biologist Susanne Greenlee thinks so, and she's involved in a project to help keep these singers around for a long time.
Susanne, land steward for the Nature Conservancy in Missouri, is working with the Missouri Department of Conservation to make audio recordings of common male Orthoptera-grasshoppers, katydids and crickets. The goal of the project is to produce a tape and identification guide that will help people like you and me learn about the local composers of our summer afternoon sonatas and late night fugues.
Susanne hopes that one day people will be as passionate about crickets, katydids and grasshoppers as they are about butterflies. "It's easy to appreciate butterflies because they dazzle us with their beauty, but it's a little harder when it comes to crickets and katydids. To most people they're voices without owners."
The first owner Susanne introduced me to was a handsome katydid whose scientific name means, "I dance in meadows." She caught him right in my own back yard going about his katydid business. When she let him go, his wings caught the sunlight like tiny windows, and I knew I'd always remember who he was.
There are 142 species of Orthoptera in Missouri, 20,000 worldwide. Grasshoppers make up a good portion of the count with only a few species causing harm to Missouri cropland. Most are benign, gentle creatures, with names like handsome grasshopper, green grasshopper and bunch grass grasshopper, that are an important food source for more than 200 species of birds. Grasshoppers spend the warm summer days grazing among the grasses, gliding from plant to plant in a flurry of colored wings.
Crickets and katydids make up the rest of Missouri's Orthoptera population and are the voice of our summer nights. Spring field crickets tune up in the grasses of early summer, and fall field crickets (Gryllus pennsylvanicus) serenade us from the dusty yards of August. The true katydids live in the trees and many, like the large true katydid, look exactly like leaves: hence their name Peterophylla camellifolia, which means, "that being which has wings like a camellia leaf."
There's a funny little tale about an old Ozarkian gentleman who is sitting on a park bench one summer night listening to the crickets. An elderly lady joins him on the bench, smiles and begins to listen to the choir rehearsing in the nearby church. She closes her eyes and says dreamily to the old gentleman, "Isn't that beautiful?"
"It sure is," he replies, "I'm told they do it by rubbing their legs together."
That's how I thought they did it too... the crickets I mean. But the truth is, it's grasshoppers that use their legs to produce sound; crickets and katydids use only their wings.
On a bright September morning as Susanne and I drove to one of her research sites, she told me more about the musicians whose tunes jam the airways on sultry summer nights. Crickets and katydids produce sound by means of a ridge-and-file system. They call by scraping the fixed ridge on the edge of their forewing against the file on the underside of the other wing.
Grasshoppers have several ways of producing sound. The most common way is by scraping the teethlike structures on their hind legs against a vein on their outer wing covers. These sounds usually are not loud enough to be picked up by the human ear. Some grasshoppers produce sound when they fly, and this noise, familiar to all of us, is reminiscent of playing cards hitting the spokes of a bicycle wheel. The clicks are made by pumping blood into the wings during flight and then popping them closed.
But why do these tiny creatures go to so much trouble to produce sound? Are they serenading us? I like what writer and naturalist Sue Hubbell has to say about them in her book, Broadsides From the Other Orders. "None of them care about our doings; they sing not of lies or murders but of their own affairs."
Most of the time it is the males that sing of such "affairs," and much work has been done to decipher just what it is they are trying to say. We now know they have courting calls, population spacing calls and aggressive calls, all of which serve a purpose in lives perhaps as complex as our own.
After listening to Susanne, I learned that male crickets are fierce competitors. The reason? Females are attracted to the loudest singer. When you hear a chorus of male crickets they are trying to jam each other's frequencies so their call will stand out. But sometimes it is to their advantage to cooperate, so two males will join in a rivals' duet, singing at the same intensity to attract as many females as possible.
I was impressed with the tenacity of these macho crickets and could picture them stalking their leaf corners, antennae waving, wings full of tunes. But Susanne wasn't finished impressing me.
"Among cricket populations there are 'satellite males' that don't call," she says. "They just hang out, hoping to mate the lovesick females attracted to the singers."
When I ask Susanne why the satellite males don't use the courting call, she cited some surprising reasons. It turns out that the cricket's moonlight serenade is risky business. Calling males use 35 times the energy of resting males. The more quiet types may get fewer females, but the extra energy boost may help them dodge a predator. It's also documented that a certain parasite that feeds on crickets finds its host by following the call it makes... another good reason not to get out your song book.
So far, Susanne and I had talked about wild Orthoptera (I thought that was the only kind), but when she began telling me about "Chinese cricket culture," I realized there was another side to the story.
People who have seen the movie The Last Emperor will remember the final scene in the film where the elderly emperor takes out a dust-covered cricket pot from under his chair and passes it to a little boy. The scene is meant to paint a picture of "Chinese cricket culture." China has a 2,000-year history of keeping singing insects as pets, an act of reverence toward the tiny singers who mark the changing seasons with their comings and goings.
Susanne visited the Nelson-Atkins Museum of Art in Kansas City to view their collection of Chinese cricket cages, much like the one portrayed in The Last Emperor. These cricket pots are exquisite domiciles designed with jade and ivory lids and special sound chambers to amplify the singing of their insect residents.
Susanne told me that some Chinese crickets were used like watch dogs. "The cricket called all night unless someone entered the bed chamber. When the calling stopped, the sudden silence would wake the master of the house and alert him to the presence of an intruder."
Other households taught their crickets to fight. During a match which, according to Susanne, was watched with the same enthusiasm as a present-day football game, they poked the crickets with specially-made straws, called ticklers, to induce aggressive behavior.
But it's a long way from Beijing to Branson. More than likely we won't trade our Dobermans for watch crickets or quit watching Monday Night Football in favor of a clash between a pair of pennsylvanicus. But it is our responsibility to preserve the habitat of the wild species who share our yards and woodlands.
Susanne said that one of these wild singers, the prairie mole cricket (Gryllotalpa major) may be in trouble. This orthopteran member is what we call a remnant dependent species. He can only survive on high quality prairie sod, a commodity fast disappearing on the planet. "If we lose the habitat, we lose the species."
Susanne described Gryllotalpa major as "not much to look at really, but he does such an amazing thing. He builds an echo chamber in his burrow under the prairie sod and by using the chamber, he can produce a sound that can be heard up to 1/4 mile. He's a big guy with a low voice," Susanne says, "definitely a bass."
Susanne apologizes when she gets out what she calls her "cheat sheets" to check a certain marking or the shape of a particular ovipositor-the organ females use to lay their eggs. But she shouldn't. She's a careful investigator with a passion for her subject. She believes these smallest of creatures matter, and the more we know about them, the better we can protect them.
When Susanne works, she says she enters a zenlike state. Stalking insects becomes her meditation time and helps her keep her focus. The day I was with her, that focus was keen. "Listen. You'll hear a faint tinkling sound at your feet." I listened. Like ice cubes clinking against the side of a glass, the call of a tiny cricket drifted up from the forest floor. Susanne parted the decaying leaves and I saw him. A dab of shoe polish, a drip of ink... one hop and he was gone.
Crickets, katydids and grasshoppers don't live long. They make their debut in the spring as nymphs with small wings and immature reproductive parts. Over the summer, they go through a series of molts, reaching adulthood in early fall when their wings and reproductive organs mature and they are able to mate.
It is in this adult stage that the male begins his courting call. Once mating takes place, the female lays her eggs (in the ground in the case of grasshoppers; on the bark of trees, along twigs or in plant stems in the case of crickets and katydids) and their purpose is fulfilled; in a single season they have grown old.
As the harvest moon waxes, the voices from field and woods grow weaker. With the first frost, they perish. But this great die-off is not the end. Their progeny sleep within the eggs until the warm nights and plentiful rains of another spring call them forth.
The year has come full circle, and once again the Ozark night is full of song. Close your eyes, sit beneath the moon and listen to "a little night music." Now you know the composers.