StoryImage( ‘/Images/Story//Auto-img-119074579116732.jpg’, ‘Photo by Dr. Robert A. Hedeen’, ‘The dark greenish color of the dogday cicada distinguishes it from the reddish periodical cicada.’);
Many individuals in the Rock River Valley thought with the passing of July, the nuisance of the cicada invasion was over. That supposition is certainly true of the 17-year periodical cicada that emerged in June, reproduced, and rapidly went underground for another 17 years.
But, there is another type of cicada that is emerging at the present time and is called the dogday cicada. The heat of summer during the so-called dog days stimulates this species to emerge from the soil and repeat the nuisance caused earlier by the 17-year periodical variety. Dogday cicadas emerge every year about this time and can pester us more than their periodical cousins. Most of us are familiar with the annoying buzzing sound created by the periodical type, but the volume of sound made by the dogday type is much louder and more irritating.
Some years ago, I was teaching a class in September at the university in a room with no air conditioning. The windows to the classroom had to be opened to encourage cross ventilation, and dogday cicadas were tuning up to a high pitch. The buzzing sounds increased to such a point that I had to speak louder and louder, and students were taking bets when I would give up and dismiss the class. The noise became so deafening that I finally had to do just that.
Dogday cicadas are sometimes called harvestflies as their emergence each year coincides with the harvest of some crops. The complete life-cycle of the dogday is largely unknown to entomologists as several species are involved. We do know that they spend at least four years, perhaps up to seven years, in their subterranean nursery before becoming sexually mature and emerging. Some emerge each year to bug us. They mate, and the eggs hatch into nymphal cicadas that quickly bore into the soil ,where they feed on the rootlets of various plants.
Dogday cicadas are blackish in color with greenish markings, and periodical cicadas have reddish wing veins and eyes. All cicadas are harmless to man, even though they have piercing, somewhat menacing mouthparts. The damage they do to plants is usually not significant, and large-scale control measures are not required.
Cicadas are relished as food by many animals, including birds, small mammals, and an occasional human who finds their taste similar to that of an avocado. Once on a field trip with a cicada expert, we dined on cicada paste on saltine crackers, and I must admit this was not an unpleasant experience.
A member of the sand wasp family Sphecidae is called the cicada killer because it has incorporated the cicada into its life-cycle. This wasp burrows a hole in the ground and goes hunting for a cicada. Once one is located, the wasp stings its prey, but it is not killed. The cicada is then dragged to the nest, and eggs are laid on the comatose cicadas body. The wasp eggs hatch into larvae, which feed on the paralyzed cicada, providing a fresh supply of food for the duration of the development of the wasp.
The cicada killer wasp rarely stings man, so if you leave it alone, it will leave you alone.
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 Sept. 26 – Oct. 2, 2007, issue