Wednesday, May 1, 2013

The Cicada Song

By Patrick J. Walsh

Walking in the park near twilight in these early days of Spring, when the shadows stretch deeply onto the far bank of the pond, it is difficult to miss the odd humming sound in the air.

The unmistakable murmur of cicadas in the midst of their mating ritual, the droning buzz rushes out across the surface of the water like a swarm of bees passing through a hollow log.

It is an evocative music, the cicada song. For the wanderer in the park, it recalls magical nights of summers long past, and the hidden joy of sudden encounters with the living presence of nature in the midst of a warm summer's evening.

In the case of the insects themselves, however, the humming represents the soundtrack of a brief, remarkable cycle of life that bespeaks both the wisdom and the wonder of nature's strange logic.

While "annual" varieties of cicadas appear every year, the particular insects now in the park are most probably of the Magicicada genus — the so-called "periodical" cicadas.

These cicadas live underground for a period of 13 or 17 years, and then emerge in massive numbers for a brief mating period before they die, leaving their progeny to begin again the long cycle of nurture underground.

The sound of the cicada's song is produced by the rapid vibration of membranes on the insect's abdomen. The vibration of the membranes, which are properly known as tymbals, produces a chirping that is then amplified by chambers within the creature's respiratory system. Male cicadas "sing" the song in large choruses to attract females.

In accordance with the science of the identification system devised by entomologist C. L. Marlatt in 1907, the insects in the park are most likely Brood II cicadas, of the 17-year variety.

It is the poetry of their appearance, however, that leaves a lasting impression. After 17 years underground — a period in which the human world routinely sees the utter transformation of leading personalities and technologies and societies — these tiny creatures struggle upward through a foot or more of soil to emerge, all at once, in the still-chilly air of the early hintings of summer.

They spend their brief time on the surface in the pursuit of a mate, in the interest of ensuring the propagation of their species. Then, after a period of several weeks to several months, their course is run, and their song withers to the last few chirrups of those who remain at the end, like the sound of a valiant heart drumming its last in the moments before death.

As all falls silent, the purpose of the cicadas' brief time on the surface is accomplished in the production and hatching of their eggs, ensuring the promise of a new generation.

The newborn nymphs fall like raindrops from the twigs where the eggs were laid, and upon landing on grass or soil, they burrow downward, to begin another long cycle of life underground.

Meanwhile, their song sung, the adult cicadas die off. The tone and timbre of their particular sound vanishes once more from the landscape, hidden away in the dust of the Earth and the promise of their descendants, not to be heard again until the first chilly days of Spring, 17 years on...

© Patrick J. Walsh

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