StoryImage( ‘/Images/Story//Auto-img-11793334371466.jpg’, ‘Photo courtesy of www.awon.org‘, ”);
StoryImage( ‘/Images/Story//Auto-img-11793335393091.jpg’, ‘Photo by Dr. Robert A. Hedeen’, ‘The exterior skeleton of a cicada that has just emerged after 17 years underground.‘);
Late in the summer each year, residents of the Rock River Valley are annoyed by the buzzing of the myriads of dog days cicadas. These insects are incorrectly called locusts by some, but they are only distantly related. A locust is a grasshopper, and early settlers confused the occasional horde of cicadas with the biblical plague of locusts.
In addition to the type of cicada that emerges each year, there are other types that remain underground for 13 or 17 years before emerging to inundate the landscape in great numbers. These are called periodical cicadas. If patience is a virtue, the periodical cicada is certainly the most virtuous of all animals, having to spend years underground before it can emerge into the light of day.
There are two types of periodical cicada in Illinois. In the southern part of the state we find the 13-year cicada, with the northern half of the state being infested by the 17 year variety. The northern brood, which will emerge in late May of this year, is the largest known anywhere. Studies done in the 1950s and 60s in an area just south of Chicago revealed an estimated population of these insects to be about 1.5 million per acre. This brood emerged in 1990, and it is reported that in some areas of Chicago, people had to use snow shovels to clear their sidewalks of the dead insects. This same brood will emerge in our area this year, 17 years later.
Biologists have long been puzzled as to why these insects are required to spend years underground before they are reproductively mature and capable of perpetuating the species. All of this preparation for life in the upper world hardly seems worthwhile, since the cicada enjoys its freedom and sexual maturity for only a few days as it dies soon after mating.
During the few days of its adulthood, the male makes as much noise as he can, singing loudly and shrilly to attract a female. Perhaps he is lucky in one respect because the female has no sound-producing apparatus. The ancient philosopher Xerarcos observed this and remarked, Happy is the cicada, since his wife has no voice.
After mating, the female lays her eggs in slits she makes in twigs with a rapier-like structure at the posterior end of her body. In a few weeks, the young hatch and tumble to the ground, into which they burrow with the aid of their sharp beaks. The juveniles feed on the rootlets of plants, sucking out the juice. When it gets too cold for them to feed, they go into a state of suspended animation. This goes on year after year until, after about 16.75 years, their instincts tell them to free themselves from the depths, and they dig their way to the surface. After climbing up a shrub or other plant, their exoskeleton splits down the middle and the adult cicada emerges.
A few individuals have a morbid fear of these creatures, which sometimes develops into the psychological malady known as entomophobia, or fear of insects. As a matter of fact, cicadas are harmless to man and do not bite, though they have piercing and sucking mouthparts. During their brief life above ground, the adults suck the sap of tender plants, but damage is usually minimal.
And, believe it or not, these insects are good to eat. Native Americans feasted upon them, and today a few gourmands like the taste of a cicada on a cracker served as hors doeuvres. Some years ago, my friend Henry Dybas, late of The Field Museum of Natural History in Chicago, made a study of a cicada brood in Will County, Ill. Henry invited me to accompany him to the study site where he was checking on the size of the underground bugs. He told me not to bring a lunch as he would provide. As the noon hour approached, he produced a box of saltines from his knapsack and proceeded to squeeze the contents of the nymphal cicadas we had unearthed onto the crackers. That was lunch! After a period of soul searching, I joined him in this unusual repast. The cicada spread on the crackers resembled a homogenized paste of avocados and had the slight taste of almonds.
I dont think, however, that canned cicada paste will soon be a common item on the shelves in the gourmet section of the supermarket.
Dr. Robert Hedeen is a former resident of Marylands eastern shore and resided in the Chicago area from 1960 to 1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.
from the May 16-22, 2007, issue