Nobody is neutral about periodical cicadas. They are either a nightmare or an awe-inspiring spectacle when they emerge in mind-boggling numbers in various parts of the eastern United States every 13 or 17 years. Males “choruses” reach deafening volume, all to attract the opposite sex. Soon, the population known as “Brood V” will erupt over eastern Ohio, much of West Virginia, the southwest corner of Pennsylvania, extreme western Maryland, a sliver of northern Virginia, and a part of Long Island, New York.
What are Periodical Cicadas?
There are seven species in the genus Magicicada. Three have a 17-year life cycle, four have a 13-year cycle. The overwhelming period of time is spent as a nymph, underground, sucking the sap of plant roots. The adult stage lasts only weeks. European settlers mistook them for “locusts,” the only populous insects they knew of.
Why the Weird Life Cycle?
The answer to this question remains a mystery. Some scientists think that it evolved as a strategy against a specialized predator or parasite. One fungus still takes a heavy toll on the cicadas. Another theory holds that the cycle evolved during the time of ice ages.
But I See Cicadas Every Year
Many other species of cicadas emerge in small numbers every year because their life cycles are staggered, not synchronous like the periodical cicadas. It takes 5-7 years for an “annual” cicada to mature, but there will almost always be an emergence each year.
How Many Broods Are There?
There are 15 active broods, each assigned a Roman numeral. Additional broods have gone extinct over the centuries. Thirteen-year broods occur from extreme southern Iowa and central Illinois to Louisiana, eastward through Alabama, northern Georgia, Tennessee, and the western half of the Carolinas. Seventeen-year broods are found in the northeast from New York to Tennessee and Virginia, the Great Lakes, Iowa, southeast Nebraska, and eastern Kansas, Oklahoma, and northeast Texas.
Can Periodical Cicadas do Damage?
The noise made by the males can be a literal headache. Females may flock to motorized gardening equipment that generates the same sound frequency as the songs of male cicadas. Females deposit eggs in twigs of living trees, often breaking the twig and causing “flagging” where the foliage beyond the break dies.