Wednesday, August 12, 2009

Dog-day Cicadas



The first photograph shows a cicada that visited my parents' porch. I placed the cicada on a newspaper and transported it to the sidewalk, where the light was more favorable for photography. The cicada bore this fuss with all the stolid passivity of a senior government bureaucrat. (The fuzziness of the image is due to my camera focusing incompetence rather than any high jinks on the part of the cicada.)

The second photograph is a cicada glamor shot from Wikipedia. The cicada, sensitive about its wide-set eyes, prefers to be photographed in profile.

My cicada is a member of the annual or "dog-days" cicadas. They appear in July and August every year. The annual cicada is considered commonplace and lacks the show-biz magic of the 17-year locust (dubbed Magicicada by star-struck biologists).

The cicada resembles a scaled-up mutant housefly. (This unnerves people who worry about the possibility of mutant bumble bees as big as sparrows or mutant grasshoppers as big as cowboy boots.) But we note, often by disparaging remarks, that the cicada lacks the housefly's acrobatic flying skills. "The cicada is slow and awkward," we sniff. Geometry makes all the difference. For a cicada that is ten times longer than a housefly, the cicada's wing area, increasing as the square of the length, is a hundred times that of the housefly. The body volume of the cicada, increasing as the cube of the length, is one thousand times that of the housefly. Therefore, the cicada should be expected to have ten times the difficulty in keeping its body airborne.

The cicada does the best it can. Any man of late middle age who attempts the somersaults of his childhood will soon understand the disadvantages that come with increased length and girth.